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ISSN 1729-830X ISSN 1729-830X
Volume 3 3 •• Number Number 2 2 •• 2007 2007 Volume R25 R20
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Science for for South South AfricA AfricA Science
ISSN 1729-830X ISSN 1729-830X
Volume 3 3 •• Number Number 2 2 •• 2007 2007 Volume r25 r20
All on board! T
A c AA cdAedmeym yo fo fS c I eI eNNccee ooff SS o h AAffrrI c I cAA Sc ou u tt h
Section of a fish skeleton cleaned by Dermestid beetles (Dermestes maculatus). Photograph: Heather Jackson Photography, Port Elizabeth. Reproduced courtesy of the South African Institute for Aquatic Biodiversity. SCIENCE FOR SOUTH AFRICA
Editor Elisabeth Lickindorf Editorial Board Wieland Gevers (University of Cape Town) (Chair) Graham Baker (South African Journal of Science) Anusuya Chinsamy-Turan (University of Cape Town) George Ellis (University of Cape Town) Jonathan Jansen (University of Pretoria) Colin Johnson (Rhodes University) Correspondence and The Editor enquiries PO Box 1011, Melville 2109 Tel./fax: (011) 673 3683 e-mail: email@example.com (For more information visit www.assaf.co.za and www.assaf.org.za) Advertising enquiries Barbara Spence Avenue Advertising PO Box 71308 Bryanston 2021 Tel.: (011) 463 7940 Fax: (011) 463 7939 Cell: 082 881 3454 e-mail: firstname.lastname@example.org Subscription enquiries Meg Kemp and back issues Tel./Fax: (012) 804 7637 or (011) 673 3683 e-mail: email@example.com or firstname.lastname@example.org
he opening of the new SAIAB Collection Facility is cause for celebration – the specially designed building to house the ‘wet’ fish collection of the South African Institute for Aquatic Biodiversity is a great achievement, representing the way science works when many different kinds of people work together towards a common purpose. Take the building itself. It’s the basis for everything that goes on inside it (p. 4). The details of constructing it involved ichthyologists who knew what they needed, combined with the expertise of the architect, project manager, and engineers of all kinds (p. 4). To build and secure a nation’s research capacity, institutions and governments have to invest in infrastructure as well as in the people who turn bricks and mortar into centres of knowledge. Where investment falls short, so does the science. The right infrastructure combined with the right people creates a setting in which individuals and their research projects can flourish, uncovering information that can help many communities of people. Farming success, for instance, can depend on looking after insect pollinators and predators such as bees and wasps (p. 36). For the fishing industry to survive, national fish stocks have to be secured, so it helps to know how and where fish larvae form, and how to help them to grow to adulthood and procreate (p. 29). For knowledge to be useful, it has to be collected and stored, cherished and nurtured, and disseminated as quickly and efficiently as possible. The nation’s collections are vital. Be they libraries or databases (p. 10 and p. 12) or nature reserves in which our living biodiversity is legally protected – they are the information storehouses of the future. Crucial too is bringing order to what’s known – naming and cataloguing as new facts come to light, and defining and redefining when necessary. Recognizing and saving the Earth’s living species needs taxonomists to tell us what’s there, geneticists to work with the DNA, and information technologists to make all the facts accessible. On the macro scale, as astronomers explore the Universe and make new discoveries, even planets have been redefined, although it meant demoting Pluto and bringing the number in the Solar System down to just eight (p. 24). Looking into the past can help us avoid the mistakes of others – and be inspired by successful pioneers who led the way (p. 14). The further back we explore, the more we can understand of our own origins in prehistory – and take pride in the new evidence that humans most probably did come out of Africa (p. 18). This issue of Quest proclaims the core processes of science, the buildings that house it, and the people who collect, conduct, and share it – all the way to every member of the public who benefits from it.
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Elisabeth Lickindorf Editor – QUEST: Science for South Africa Join QUEST’s knowledge-sharing activities Write letters for our regular Letters column – e-mail or fax your letter to The Editor. (Write QUEST LETTER in the subject line.) ■ Ask science and technology (S&T) questions for specialist members of the Academy of Science to answer in our regular Questions and Answers column – e-mail or fax your questions to The Editor. (Write QUEST QUESTION in the subject line.) ■ Inform readers in our regular Diary of Events column about science and technology events that you may be organizing. (Write QUEST DIARY clearly on your e-mail or fax and provide full and accurate details.) ■ Contribute if you are a specialist with research to report. Ask the Editor for a copy of QUEST’s Call for Contributions (or find it at www.assaf.co.za or www.assaf.org.za), and make arrangements to tell us your story. To contact the Editor, send an e-mail to: firstname.lastname@example.org or fax your communication to (011) 673 3683. Please give your full name and contact details. ■
Treasury of fishes
Treasury of fishes Opened on 23 March 2007, the new SAIAB Collection Facility brings the National Fish Collection firmly into a 21st-century research setting – scientific treasure of the richest kind. Members and associates of the South African Institute for Aquatic Biodiversity (SAIAB) explain what a natural history collection is and does. How are fish specimens prepared? How did architects and engineers design and construct the new building? Storehouse and specimens yield useful information. Taking DNA samples and ‘barcoding’ them lays the groundwork for identifying fishes – to conserve the nation’s stocks, and to help forensic teams catch up with poachers. Add instant online access to the latest data via the new SAIAB Information Portal, and the world’s expertise is at your fingertips. Celebrating this top-of-the-range facility also means recalling pioneers of the past, whose vision, energy, and passion for knowledge built the foundations for a wealth of achievements, then, now, and to come.
SAIAB fish specimens.
Photograph: Courtesy of SAIAB. Heather Jackson Photography, Port Elizabeth
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Preservation Kholiwe Dubula and Nomtha Myoli go through the process of preserving fishes.
reserving a fish collection for long-term storage involves long-established as well as continually improving procedures and practices. It’s a complex process to bring specimens from field to formalin and eventually into final preservation liquids for current and future scientific study. The South African Institute for Aquatic Biodiversity (SAIAB) Collection Facility houses different collections, preserved and prepared in different ways, with different uses. SAIAB curates wet collections, dry collections, biomaterials, and images, and receives fish specimens from various sources. Most are collected during field trips by SAIAB’s researchers; others come from gift exchanges with museums and research institutes elsewhere in the world or as donations from members of the public.
Photograph: Courtesy of SAIAB. Heather Jackson Photography, Port Elizabeth
Stages of collection: After the field trip where specimens are collected, fishes are brought back to the facility where they are prepared for long-term preservation in clearly labelled glass jars (checked to make sure that all of them are properly closed) and stored on the collection shelves.
For picture captions, see page 9.
The wet collection During field trips, researchers normally ‘fix’ specimens in 10% buffered formalin diluted with water. Formalin fixes tissues or cells by irreversibly cross-linking primary amino groups in proteins with other nearby nitrogen atoms in protein or DNA. Handling specimens correctly before, during, and after fixation is very important so as to preserve as much biological information as possible. Specimens are identified when they are brought into the collection from the field. If a specimen was not fixed before arrival – if, for example, it was a frozen object donated by a member of the
Building the new SAIAB Collection Facility The technicalities of designing and constructing a specialized museum facility pose many challenges. Client, architect, and engineers tell their story. The client’s brief Paul Skelton, South African Institute for Aquatic Biodiversity Many scientists and curators of wet natural history collections put blinkers on when they view a fish collection first of all as a collection of fishes and, second, as a volatile chemical store. In practice, where costs and staff safety are paramount, the order is reversed. Moreover, in South Africa and most other countries, strict laws govern the housing and storage of volatile chemicals – but none governs the technicalities of storing and
4 Quest 3(2) 2007
caring for natural history collections. The new wet collection facility for the National Fish Collection at the South African Institute for Aquatic Biodiversity (SAIAB) had to accommodate the considerable risks that a large natural history collection of this kind entails. In terms of occupational health and safety, two factors were paramount: first, the exposure of curators and other users of the collection to harmful volatile liquid preservatives and their vapours; second, the flammable nature of these preservatives. A small collection carries fewer risks, but when it is as large as the National Fish Collection,
they are substantial. Our situation was particularly urgent as the existing storage of the National Fish Collection was on the ground floor of the SAIAB building. Potential exposure to harmful volatile chemicals would affect not only collection staff but also people using the rest of the building. The fire threat was also a problem. The collection room itself is well-protected with specialized equipment, but a fire could begin anywhere in the building’s offices and laboratories. It was therefore decided to construct a new off-site wet collection facility.
Top, middle, and below: To help with later research, fish specimens are cleared and stained with chemicals, which reveal the bone (red) and cartilage (blue). All photographs: Courtesy of SAIAB unless otherwise indicated
Project management and quantity surveying services Peter May, KWMH Quantity Surveyors, Port Elizabeth SAIAB, a facility of the National Research Foundation, and Rhodes University appointed KWMH Quantity Surveyors in late 2004 to conduct project management and quantity surveying services for the new collection facility, to be built next to the existing SAIAB premises on land owned by Rhodes University and leased by SAIAB. Once terms of lease and relocation of existing services had been negotiated, project planning proceeded in early 2005. The project had unique requirements to enable the structure to fulfil all the requirements for storing a fish collection of this size. Many aspects of the
development were straightforward, but specialized environmental treatment was needed to meet exacting – and sometimes mutually conflicting – operational and safety standards. A further (not unusual) consideration was budget – early assessments had underestimated the costs. For the facility to meet international standards, Paul Skelton, with the project manager and the environmental engineer, toured four new or upgraded European collection facilities in January 2006 – in Stockholm, Leiden, Brussels, and London. These visits were very helpful. Their findings supported design decisions already made, gave ideas for improving the efficiency with which the collection could be used, and highlighted design shortfalls and operational inconveniences that could be avoided. As a result, for example, the design of facilities for storing, mixing, and
The technical requirements were many. For efficiency and cost-effectiveness, the facility had to ■ be close to the managers and scientists working with the collection ■ provide safe storage for the collection, with maximum possible storage capacity ■ accommodate the fact that wet collections are heavy and need a lot of space ■ limit the specimens’ exposure to light and to fluctuations of temperature, to ensure their safe long-term preservation ■ cater for the safe storage and handling of bulk preservatives. Finally, building this kind of facility on a university campus such as Rhodes, and on a main thoroughfare in a ‘cultureconscious’ town such as Grahamstown, means that its appearance was important. These, in a nutshell, were the client’s main requirements.
Top left: SAIAB researcher shows interns how to use the polymerase chain reaction (PCR) machine in the genetics laboratory.
public – it is immersed in formalin in the collection preparation area for at least 48 hours to seven days, depending on the size. After fixation, the specimens are rinsed with water to remove the formalin, as it can be harmful to handle. They are transferred progressively into ever-stronger alcohol solutions – into a 30% ethanol (ethyl alcohol) solution for 24 hours, then into a 50% ethanol solution for a further 24 hours, then into a 70% solution. Ethanol preserves the fish by replacing the water content in the tissues, thus preventing bacteria from decomposing the tissues. The specimens then go into glass storage jars. The details are entered into the collection’s electronic database (called ‘Specify’), which was uniquely designed at the University of Kansas in the USA for use in museum collections. Each specimen ‘lot’ is given a unique identity (catalogue) number – a ‘lot’ consists of all the specimens of a particular species gathered in the same collection event, so a lot can contain one or more specimens. The data entered into the database include: specimen/s name(s), collector’s name, place, date, location, habitat, preservative used, number of specimens, and the storage information. A waterproof data label is printed from the database with the relevant corresponding information and placed inside the jar. The jar is then shelved in the collection room alphabetically by family, genus, and species. Included in this wet collection are cleared and stained fish specimens. These have been through a process in which a small specimen is placed in a digestive enzyme, trypsin, to clear or digest flesh (protein), making it translucent. The specimen is then treated with the chemicals
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Preservation growing collection, consisting of tissue samples taken from fish as soon as possible after capture. They are stored in 95% ethyl alcohol, or frozen, to preserve the DNA for later analysis. At this high concentration, the alcohol quickly penetrates the cell membranes, fixing and preserving the tissue. In the new SAIAB Collection Facility, these specimens will be stored in a freezer set to –80 °C to prolong their shelf life. This collection is used for genetic studies.
Photograph: Courtesy of SAIAB. Heather Jackson Photography, Port Elizabeth ▲
Top and right: Fish skeletons partially cleaned by Dermestid beetles. Middle: Dried porcupine fish specimen. Above: X-ray image of a cardinal fish (Apogon doryssa), showing the spine and fin-rays, middle vertebral column, and head and jaw-bones. The white dot is an ear-bone (otolith).
alizarin red and alcian blue, which dye the bone red and the cartilage blue, respectively. This process keeps the stained skeleton and cartilage intact and visible through the cleared, transparent muscle tissue, making osteology (or the study of bone structure) possible. These specimens are stored in 60–90% glycerin, which keeps the specimen pliable. Thymol crystals are added to the preservative to prevent fungal growth. SAIAB is developing a DNA bank – a fast-
using alcohol was revised, to improve both safety and comfort. The original project cost and programme were amended to accommodate an additional second floor. Furthermore, the weather caused delays – 2006 in the Eastern Cape was one of the wettest years in the rainfall record!
The architect’s challenges Hilary Saunders, Saunders & Associates, Grahamstown Perhaps the greatest challenge for the architects was the siting of the building on a major thoroughfare in historic Grahamstown. It meant building a secure warehouse with a controlled environment, next to the existing two-storey SAIAB building, fronting onto Somerset Street – an attractive tree-lined thoroughfare boasting the major institutional buildings of the Albany Museum
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The dry collection The dry collection consists mostly of fish skeletons. Specimens undergo a skeletonization process in which carcasses are placed in a sealed box with dermestid beetles (Dermestes maculatus) and larvae. The dermestids eat the flesh off the bone, leaving clean whole skeletons within a few months. The new facility has a room designated for this process, as the rest of the building needed to be sealed off from the beetles. This collection is used for osteology studies. The skeletons are stored in airtight plastic containers in the dry collection cabinets to prevent damage from insects and mould. Included in the dry collection cabinets are shark jaws, fish bones, scales and skins, and lungfish cocoons. The image collection The image collection consists of microscopie images, photographs, slides, radiographs, paintings, and scientific drawings and illustrations. Photographs and slides capture sampling methods, live fish in their natural habitats, and the specimens’ original colours before these are destroyed in preservation. There are images of fish viewed under a
complex, Rhodes University, the High Street intersection, and many 19th-century houses, as well as the buildings of St Andrews College further north. The Town Planning Scheme permitted a two-storey building, covering 75% of the site. Initially, only one storey was to be constructed, but the design included The SAIAB Collection Facility: east elevation.
a second storey for future expansion. After work had started, however, SAIAB took the decision to add the shell of the second storey during this first construction stage (at today’s prices), to save costs and inconvenience later. Drawings were revised, and the storage facility can now accommodate more collections without
Q Fact file The National Fish Collection 1938: J.L.B. Smith went on his first collection expedition to Mozambique with his wife, Margaret. He housed his collection in Grahamstown’s Albany Museum. 1947: Smith moved his private collection from the Albany Museum to Rhodes University’s new Department of Ichthyology, where he was appointed professor and head. 1975: The collection had grown to over 10 000 lots and was moved into the collection room of the SAIAB building (then known as the J.L.B. Smith Institute of Ichthyology; its first director was Margaret Smith). The collection ■ spans more than 125 years of collecting, with records revealing the oldest specimen dating back to 1880: the flathead mullet (Mugil cephalus); the oldest South African specimen in the collection is the largescale yellowfish, Labeobarbus marequensis, collected in 1887 in Pretoria ■ has the largest collection of African fish on the continent, with the most comprehensive collection of southern African fish in the world ■ consists mainly of South African freshwater, estuarine, and marine specimens, but also houses specimens from 170 countries ■ holds about 400 fish families in 80 000 accessioned lots comprising over 650 000 fish specimens ■ includes one of the world’s largest collections of coelacanth (Latimeria chalumnae) specimens ■ has the only record of an albino great white shark, Carcharodon carcharias, caught and donated to the Institute in 1997 (albinism is the absence of melanin in the skin and eye, a rare recessive condition that leads to the pale skin; albino fish are scarce because the absence of their normal protective camouflage makes young fish easy targets for predators) ■ preserves the most venomous fish in the sea, the stonefish (Synanceia verrucosa), which can kill a victim within an hour of injury. (This fish has toxin glands at the base of its dorsal-fin spines, and injects the toxin through these spines. It is found in rock pools, mainly in tropical– subtropical areas such as those of KwaZulu-Natal and Mozambique.)
microscope, and radiograph facilities produce images used for osteology. A resident scientific illustrator is responsible for scientific drawings, which go into publications such as books. Some images are stored in filing cabinets, and most are available online through the SAIAB website. Who uses the collection? The collection provides a resource for taxonomic and systematics research, as well as for ecological, phylogeographic, and genetic studies. It’s used by SAIAB’s own researchers, but specimens are also lent to other scientists in South Africa and abroad, and visiting scientists conduct research using the collection’s specimens. The collection and its associated database also form an historical archive of fish from all areas around our country and beyond. Specimens are used extensively for education, providing insights into our diverse fish fauna to fascinate new generations of young South Africans. ■
The type collection The most valuable part of the facility’s wet collection is the type collection, which is stored separately, with special care and with additional security. ‘Types’ are the specimens used for scientific species descriptions. The rest of the wet collection consists of voucher specimens (that is, those relating to specific published research studies), which include parts and whole specimens stored in alcohol. Among the treasures in the type collection is the holotype (a first finding) of the six-gill stingray, Hexatrygon bickelli. The holotype ranks highest among type specimens. It is unique in that it is the reference specimen for the species name, and serves as a point of comparison when other specimens are thought to belong to the same species.
Kholiwe Dubula is a collections manager and Nomtha Myoli is a communications officer at SAIAB. For more about the National Fish Collection, visit www.saiab.ru.ac.za
The wall buttresses of the existing SAIAB building were replicated and used to accommodate the rainwater downpipes of the new building. The corners have been chamfered to establish a rhythm across the façade of both buildings and to accommodate the ventilation ducts. The entire street frontage is set back from the boundary with the pavement, and a raised area behind the perimeter fencing is to be landscaped with plants endemic to the Eastern Cape region, shown off by the building’s natural brickwork. Over the longer term, the edge of the street in front of the existing building will also be developed and the landscaping extended to integrate the old with the new. Improvements to the site will incorporate public information kiosks and opportunities for passers-by to connect with the interesting activities of the SAIAB complex. ▲ ▲
further expense or delay. The design of the layout of the SAIAB Collection Facility included a perimeter zone on the western edge housing mechanical and electrical services equipment, thus creating a buffer to protect the internal storage area from the heat of the sun in the west. The southern edge of the building comprises reception and delivery space, wet specimen preparation rooms complete with automated systems for delivering formalin and alcohol, and a storeroom for alcohol and containers. The remaining area is the large storage facility containing movable and non-movable storage systems – including very large containers that house fish up to three metres long. The movable shelving layout has been designed to be accessed by trolleys, and lighting zones were created to control levels of light and keep them to a minimum.
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Building the new SAIAB Collection Facility
Civil and structural engineering Peter Ellis, MBB Consulting Engineers (EC), Grahamstown The type of structure to be erected was governed by a geotechnical investigation of the site, which lies on an old river bed consisting of seven metres of alluvial deposit on tillite bedrock. The alluvial material is unstable and has low bearing pressure, so we designed a piled foundation system to support a reinforced concrete slab for the ground floor. A total of 46 piles, 600 mm and 750 mm in diameter and six metres apart to form a grid, were installed and interconnected by a series of ground beams and a 220-mm-thick reinforced ground-floor slab. This meant that the building could rest directly on the bedrock below. A further grid of columns supports the second floor and roof trusses. A maze of pipes and ducts (to convey water, sewerage, stormwater, and cables) was installed under the road and parking area, which was then surfaced with 80-mm concrete interlocking pavers.
Electrical/mechanical/ air-conditioning services Craig Clarke, Clinkscales Maughan-Brown, Port Elizabeth This facility required highly specialized mechanical and electrical engineering. Three main factors dictated the design: ■ the hazardous nature of alcohol solutions used to prepare and store the specimens ■ the sensitivity of the specimens to longterm exposure to light ■ the need to maintain the specimens at a controlled and constant low temperature. The concentrated alcohol solution used for storing specimens has a low flashpoint at normal ambient temperatures, which affects the design of each of the mechanical and electrical services. Standards South Africa was commissioned to produce a report, which concluded that the SAIAB Collection Facility should be classified as a hazardous location because of the possible presence of dangerous concentrations of flammable gases. This
report formed the basis for designing and selecting equipment for the fire protection systems, the electrical installation, and the air-conditioning and ventilation plant. A standard sprinkler fire-extinguishing system was chosen, as it is reliable, simple, easy to operate and maintain, and costeffective. It uses water from the municipal water supply as the extinguishing medium, and was specially designed for fires involving flammable liquids. A flow switch in the sprinkler system, linked to the building management system, automatically triggers an alarm if a fire breaks out, and manual break-glass fire-alarms serve as a back-up. There are also hand fireextinguishers and hose-reels throughout the building. All electrical equipment in the areas classified as hazardous is specially designed, with specialized cabling systems. Apparatus – including lights and switches – is sealed against flammable gases so that no electrical spark will ignite them. Metal equipment is carefully earthed to guard against static electrical discharges, with additional earthing straps and clamps to allow the earthing of portable containers brought into the building. The fish specimens are sensitive to longterm exposure to light (more specifically to ultraviolet light), so the lights in the wet collection room are operated in rows from outside the room to make sure that only essential ones are switched on at any time. The lighting is constantly monitored by the building management system to make sure
1. The rate of alcohol evaporation from the specimen containers was measured and used to calculate the air change rate. Only one facility at the various institutions visited in Europe had made a similar calculation and had arrived at almost exactly the same answer.
Construction photographs (pp. 4–9): 1 The site for the SAIAB Collection Facility. 2 Clearing the site. 3 Piling process in operation. 4 Laying the foundations. 5 Preparing the suspended ground floor. 6 Grounded floor shuttering. 7 Grounded floor slab with columns. 8 Shuttering beams to support the first floor. 9 Shuttering for the first-floor slab. 10 First-floor slab partially complete. 11 First floor in place. 12 First-floor columns. 13 The building goes up another floor. 14 Ring beams support the roof. 15 & 16 Roof trusses. 17 Roof sheeting. 18 Constructing the access to the first floor. 19 The first floor (showing trusses). 20–22 The structure nears completion. 23 Entrance to the building. 24 Erecting the mobile shelving. 25 The preparation room. 26 Roofing complete, the external brickwork is constructed. Images: Courtesy of Peter Ellis of MBB Consulting Engineers (EC)
that lights are off whenever the room is unoccupied. Arguably most challenging of all was the design of the air-conditioning and ventilation system. A cool, constant temperature of about 16–18 °C has to be maintained in the room to preserve the specimens and assist with safety. Keeping the wet collection store at 18 °C or below ensures that the temperature of the alcohol solution stays below the flashpoint (21 °C for a 70% solution). Also, to save energy, exhaust air from the building should be kept to a minimum, and the advantage of lower temperatures is that they reduce evaporation rates1. The normal operation of the heating, ventilation, and air-conditioning (HVAC) system is designed to remove excessive alcohol fumes and to maintain the environment in the store at a level that is safe for staff. The concentration of alcohol fumes is constantly monitored by specialized detectors in the store. Should the fume concentration rise above 10% of the lower explosive limit, the building management system will sound the alarm and start up the emergency fume extraction fans. An emergency generator makes sure that electrical power is always available to all essential circuits. In summary, the mechanical and electrical building services have been designed to provide a state-of-the-art solution comparable to any elsewhere in the world, yet they are simple and cheap to operate and maintain. ■
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Voucher specimen e.g. in the SAIAB National Fish Collection
Public users Collection data e.g. locality
DNA tissue samples
Barcode of Life Data Systems
Other barcoding campaigns...
South Africa has joined the global effort to create a reference database for the world’s fish species. Monica Mwale and Ernst Swartz explain what’s being done and how useful it will be.
DNA barcoding facility DNA extraction, PCR, & sequencing
DNA barcode Images: Monica Mwale unless otherwise indicated
Top left: Information linkages to voucher specimens for public users of the online DNA barcode species reference, Barcode of Life Data Systems (BOLD). Left: The double-stranded circular structure of mitochondrial DNA (mtDNA), showing the inner L-strand (yellow) and outer H-strand (orange) as well as the genes and regulatory regions. The COI (cytochrome c oxidase subunit 1) region is marked in green and is a short region of the heavy strand. In animals, mtDNA consists of about 16 000 base pairs with 37 genes. There are 13 proteins or polypeptides (orange and green) that provide instructions for making the enzymes involved in oxidative phosphorylation. The remaining 22 genes (pink and blue) provide instructions for making molecules called transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs).
Biological barcoding W ith its diverse fish and biomaterial collections, the South African Institute for Aquatic Biodiversity (SAIAB) is Africa’s representative on the FISH Barcode of Life (FISH-BOL), an initiative of the Consortium for the Barcode of Life (CBOL) hosted by the Smithsonian Institution’s National Museum of Natural History in Washington, D.C. The FISH-BOL is aiming to create a reference database by establishing DNA ‘barcodes’ of all the world’s fish species, to make it possible to identify any single species, be it juvenile or adult, male or female, large or small, from just a tiny piece of tissue. Taxonomic crisis The bleak global reality is that more species have yet to be discovered and described than the number of species that we already know.
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Traditional or morphologically based methods of identifying and describing new species, needing detailed examination of specific body parts, are demanding and require interpretation by experienced taxonomists – of whom there is a global shortage. The decline in funding for this kind of research is now globally known as the ‘taxonomic impediment’. Nowhere is this problem more evident than in Africa, where few collection facilities are able to maintain and employ the taxonomists they need, to look after and work on voucher specimens (that is, specimens that support specific published studies). Effective conservation has been hampered in many regions, mainly for lack of the taxonomic information that’s fundamental for most biological studies and that’s needed to understand biodiversity. For example, taxonomic
expertise is critical in recognizing and eliminating invasive non-indigenous animal and plant species that cause the decline of many indigenous species and result in huge economic losses1. The time has come for new approaches to species identification. It’s taken 250 years to describe roughly 15% of life’s estimated diversity – now being lost at an alarming rate – so the taxonomic revolution of DNA barcoding arrives at a critical moment2. Technological advances made by other molecular studies (such as the Human Genome Project) have made the barcoding of large numbers of species economically more viable and the global programme of the CBOL feasible. People who may not be experts on a taxonomic group will be able to use DNA-based systems for identifying a species rapidly.
1. The economic damage inflicted worldwide by invasive alien species has been estimated at US$400 billion per year according to the Food and Agriculture Organization of the United Nations (FAO). 2. For further information, visit www.dnabarcoding.ca/rationale.php
DNA barcoding is specially important for Africa, whose rich biodiversity remains relatively poorly studied. It promises to speed up the discovery and routine identification of the continent’s undocumented biodiversity. DNA barcoding DNA barcoding uses a diagnostic ‘biomarker’ for species from a short gene sequence from a standardized region of the genome. The cytochrome c oxidase subunit 1 (COI) of the mitochondrial DNA region has been identified as the standard barcode region for higher animals. In most studied groups, this DNA sequence is only about 648 nucleotide base pairs long, so it’s a very small part of the entire genome (which is, for example, three billion base pairs in humans)3. The aim of DNA barcoding is to make a large database publicly available for analysis and rapid identification, thereby helping taxonomy to serve science and society more effectively. To this end, CBOL has set up the Barcode of Life Data Systems (BOLD), an online workbench that aids collection, management, analysis, and use of DNA barcodes through linkages to voucher specimens (gathered to support individual research studies) that are lodged in collections and museums. All the specimen barcode records are to be accompanied by voucher information, collection data, images, and – most important – full taxonomic accounts. This electronic database forms a public reference library of species identifiers, where users can submit ‘unknown’ sequences to match against specified sequence subsets. It will enable non-specialist taxonomists to make confident species identifications and to assign unknown specimens to known species. Establishing this database of DNA sequences linked to specimens kept in museum collections relies heavily on positive identification of species by specialist taxonomists. Only in this way can an accurate and reliable reference database be created, and museum collections and taxonomic expertise are the foundation stone for a global and accurate DNA barcode database. Conservation and forensics SAIAB’s existing biomaterial collection contains many tissues linked to specimen vouchers, images, and all the associated information necessary to designate species. The Institute’s molecular laboratory, established in 2006, is crucial in the initiative to barcode the species in this valuable
collection. Barcoding will help conservation by bringing positive identifications for all life stages of a fish and a better understanding of relationships among species across biogeographical zones – extremely useful in ecological studies of fish larvae, for instance, as most larval stages of known, common, and even widely distributed fishes have not yet been identified or described (see also pp. 29–35 in this issue). Other basic information, such as geospatial coordinates, indicates where species occur and help conservationists to establish appropriate boundaries for marine and freshwater reserves – especially in the case of organisms where prior taxonomic work has been limited and where the situation can’t otherwise improve, given dwindling taxonomic expertise. Forensics will also benefit from barcoding, for uncovering illegal trade in endangered wildlife species, in particular where only parts of the organism are being smuggled. At present, many commercially important species of sharks threatened by smuggling are difficult to identify, especially when individuals are processed at sea – by removal of head, entrails, and fins – before authorities can get to them. The trade in shark fins has been so lucrative that it accounted for more than 50% of the total Atlantic shark fishery value in 2002, so with the help of barcoding, African fisheries departments will be able to prosecute illegal fishing practices even where processing has already occurred. The 2002 Report of the Food and Agriculture Organization of the United Nations estimates that 47% of major marine fish stocks is at present fully exploited; 18% is overexploited; 10% is depleted; and only about 25% is being sustainably exploited. The predicted alarming increase in global seafood consumption and, therefore, fishing pressure is likely to increase the amount of exploitation and illegal trading even more. Law enforcement and monitoring for effective management of fish stocks is a problem in most African countries, because of insufficient resources and sparse information about biodiversity assessments. So accurate and reliable species identification through barcoding could become increasingly important in law enforcement – and vital for saving our fish species for posterity. ■
3. In a 2003 study by P.D.N. Hebert et al., COI species profiles were 100% successful in identifying lepidopteran species (butterflies, skippers, and moths). This group is one of the most taxonomically diverse orders of animals that generally shows low sequence divergences, so these results suggest that similarly encouraging results can be expected for other animal groups such as fishes.
Top: A pregnant spiny dogfish female (Squalus megalops) caught off a boat. This shark species is classified as threatened because so many individuals are caught with lines, mesh nets, and bottom trawls of the trawl fishery off southern Africa, only to be discarded as by-catch. Sharks reproduce slowly and produce only a small number of welldeveloped offspring. Juveniles of the spiny dogfish take up to two years to develop inside the female before they are born. Visit www.iucnredlist.org/search/details.php/41859/all Photograph: Phillip Heemstra (SAIAB)
Above: The amount of fish sold at fish docks is on the rise as a result of increasing global fish consumption. Monica Mwale is an aquatic biologist at SAIAB. Her research on the systematics of marine fishes focuses on the use of DNA sequence and morphological data to elucidate phylogenetic relationships. She currently runs a barcoding project on fishes of the Western Indian Ocean. Dr Swartz is also a SAIAB aquatic biologist, whose research interests include exploring and documenting aquatic biodiversity in southern Africa and the conservation genetics of threatened freshwater fish species. Ernst Swartz and Monica Mwale are currently the Chair and Vice-Chair, respectively, of the African Regional Working Group of FISH-BOL. For more, consult: Food and Agriculture Organization of the United Nations (FAO), The State of World Fisheries and Aquaculture 2002 (Rome, 2002); T.W. Greig et al., “Mitochondrial gene sequences useful for species identification of western North Atlantic Ocean sharks”, in Fishery Bulletin, vol. 103 (2005), pp.516–523; P.D.N. Hebert et al., “Biological identifications through DNA barcodes”, Proceedings of the Royal Society London B, vol. 270 (2003), pp.313–321; A.V. Suarez and N.D. Tsutsui, “The value of museum collections for research and society”, in BioScience, vol. 54 (2004), pp.66–74; P. Reddy and N. Myoli, “Barcoding Fish Across Continents – priceless science” (2006) at www.saiab.ru.ac.za/story86.htm; and E. Swartz, M. Mwale, and N. Myoli, “Barcodes for African Biodiversity” (2006) at www.saiab.ru.ac.za/one.htm.
Quest 3(2) 2007 11
Desktop access to biodiversity Willem Coetzer introduces the SAIAB Information Portal – the online way to keep up-to-date with natural history and biodiversity.
pecimens preserved in jars and their database entries are two sides of the same coin. They store and record what science has discovered about the living world and they make the information available when it’s needed – to researchers, those who manage our natural resources, the public at large – now and for the future. The 1992 Rio Earth Summit made society aware of the need to protect biodiversity – the better informed we are, Refining museum specimen records The Darwin Core Version 2 standard now requires a minimum of 46 fields to be present in the database record of a natural history museum specimen, such as a preserved fish or a pinned insect. Apart from the basic descriptions (such as the scientific name of the organism, the name and geographic coordinates of the place where it was collected, and the date that it was collected), scientists must now record further details. These include refined data on the geographic coordinates (for instance, whether they represent a locality that is the nearest second or the nearest minute away from the precise spot where the animal was caught) and the method by which the coordinates were obtained (for instance, whether it was by using a Global Positioning System instrument or by reading the coordinates from a paper map, whose geographic scale must also be specified). Even the time of day that the animal was captured can be useful information to a researcher studying the species many years later.
12 Quest 3(2) 2007
the more successfully we can organize our conservation strategies. The core data lie in natural history collections around the world (South Africa’s National Fish Collection is an example), which together hold hundreds of millions of specimens. Their mandate is to preserve and archive the material, make it accessible to scientists globally, and involve the public in sharing biodiversity discoveries. Computer technology has revolutionized specimen databases. To anyone with an internet link, detailed information is now just a few keystrokes away. Why we need online databases The information systems of the year 2007 are unrecognizably different from those of the mid-1990s. We now take for granted such innovations as graphical user interfaces and simultaneous, multiple-user access to network databases, and online availability1. (We can do banking and buy groceries just by using our personal computer, for instance!) Electronic specimen databases make the biodiversity information held in the world’s specimen collections accessible via the internet. They allow scientists, wherever they may be, to search – often in a single repository – for data on animal and plant material held in thousands of museums and collected from countless localities, saving
time and money previously spent travelling to far-off places to study specimens or physically to track down information in books and journals. Whereas curators and users of specimen collections used to rely on information in unwieldy specimen catalogues, museums can now publish their biodiversity information on the worldwide web automatically, even as it’s captured in their specimen databases, which makes updates immediately available. Thanks to the new field of biodiversity informatics, online biodiversity information is more current, more useful, and quicker and easier to find than ever before. Such databases will also, over time, make it easier to plan conservation areas that are adequate to protect our natural heritage from the damaging consequences of unsustainable resource use and development. When digital images of museum specimens are also available online, scientists can study them in minute detail in their home laboratory. Photographs are particularly important in studying fish, which lose their colour when preserved in alcohol. Recording the true colours of a live fish before it is fixed in formalin and transferred to alcohol can be very important in species identification, for example the brightly coloured wrasses2 of the family Labridae.
1. SAIAB began computerizing its specimen records in 1986 in a Dbase III database designed by Leonard Compagno of the then J.L.B. Smith Institute of Ichthyology. In 1992, the information was moved to FishNet, a custom-designed system built on Advanced Pick version 6 and developed by L. Palmer and J. McNeill of the Rhodes University Information Systems Department. For the first time, more than one user could access the specimen database simultaneously, on a newly installed local area network. 2. A wrasse is any marine perciform fish of the family Labridae. Wrasses are found in tropical and temperate seas, have thick lips and strong teeth, and are usually brightly coloured. (A perciform fish is one belonging to the order Perciformes, an order of ray-finned fishes.)
Far left: A result from a search conducted through the web interface to the SAIAB Image Collection. The image is a contribution from a fishwatcher registered with the SAIAB-affiliated East Coast FishWatch Project. Left: Details of the SAIAB Information Portal. Right: A distribution map generated during the course of the 2006 IUCN/SAIAB freshwater conservation assessment project.
Definitions Biodiversity: The variability among living organisms from all sources including terrestrial, marine, and other aquatic ecosystems, and the ecological complexes of which they are a part. It includes diversity among genes, individuals, and populations, within and between species, and of ecosystems. Informatics: Research on, development of, and use of technological, sociological, and organizational tools and approaches for the dynamic acquisition, indexing, modelling, dissemination, storage, querying, retrieval, visualization, integration, analysis, synthesis, sharing, and publication of data and information, so that economic and other benefits may be derived from them by users in all sectors of society. Biodiversity informatics: The application of informatics to recorded and yet-to-be discovered information specifically about biodiversity, and the linking of this information with genomic, geospatial, and other biological and non-biological datasets. Source: www.gbif.org/GBIF_org/facility/BIrepfin
Getting museum information web-enabled A specialist team at the Biodiversity Research Center of the University of Kansas in the USA has, for the past 20 years, been developing software specifically for managing natural history specimen collections. Their flagship product, Specify Biodiversity Collections Software (known as ‘Specify’) is used by museums round the world to organize specimen information and physical specimens and to manage loans of such material. The Specify database has a built-in web interface that uses Java Server Pages (JSP) technology, so a database manager doesn’t need to spend time making a new web page for each new set of records added to the database. Instead, to display the added records, the web interface application automatically generates a standard HTML template into which the new text or image is simply inserted. SAIAB’s publication of its biodiversity data online follows the international trend towards open access to information. The Institute is proud to be a node of the South African Biodiversity Information Facility (SABIF), the local chapter of the Global Biodiversity Information Facility (GBIF). By March 2007, the GBIF portal had already made available electronically more than 119 million specimen records and observations of life on Earth. The SAIAB Information Portal The launch of the SAIAB Information Portal coincides with the opening of the Institute’s new wet collection building (the SAIAB Collection Facility) on 23 March 2007. In addition to online images of, and specimen information about, southern African fishes (as well as fishes from elsewhere), the portal offers GIS3 maps of southern African freshwater fish
distributions and the opportunity to learn about fish classification and identification using taxonomic keys by computer. For students or academics, there are hyperlinks to library information resources, and for those with an interest in history, an account of SAIAB’s precious ichthyological texts dating back to the 16th century. The public plays its part The East Coast Fish-Watch Project4, affiliated to SAIAB, was a South African pioneer in enlisting ‘public fieldworkers’ to contribute to science by taking field-notes and photographs of animals they encounter outdoors or while scuba-diving, and offering their findings for inclusion in the scientific record. The internet is ideal for receiving, organizing, and publishing such information, and for the interaction it enables among professional researchers and the public. So, in the interests of science – ■ share your images of estuarine or marine fishes from the east coast of South Africa with the East Coast Fish-Watch Project and other fishwatchers ■ learn about fishes by visiting the homepage of the East Coast Fish-Watch Project ■ learn about terrestrial biodiversity by investigating similar initiatives of the South African National Biodiversity Institute (SANBI) and the Agricultural Research Council (ARC), which encourage the public to contribute observations of reptiles and spiders. ■ Willem Coetzer works in Information Management and GIS at the South African Institute for Aquatic Biodiversity. For more information, use these hyperlinks: the SAIAB Information Portal at http://saiab.ru.ac.za/infoportal/; The East Coast Fish-Watch Project at http://fishwatch. tripod.com/; The South African Biodiversity Information Facility (SABIF) at www.sabif.ac.za; The Global Biodiversity Information Facility (GBIF) at www.gbif.org; Fishbase at
3. GIS (Geographic Information System) is a way of using a computer database (or networked databases) to analyse spatial information (for instance, geographic coordinates of localities where specimens have been collected) and to plot and print maps. Some Geographic Information Systems are available online. 4. See Phanor Montoya-Maya and Phil and Elaine Heemstra, “Citizen Science – the East Coast Fish-Watch Project”, in Quest, vol. 3, no. 1 (pp.26–27).
www.fishbase.org; The South African National Biodiversity Institute (SANBI) at www.sanbi.org; The Southern African Reptile Conservation Assessment at www.reptiles.sanbi.org; The South African National Survey of Arachnida at www.arc.agric.za (click on Sansa). Consult O. Gon and R. Wertlen, “Fishnet, a computerized database management system for the national fish collection at the J.L.B. Smith Institute of Ichthyology”, South African Journal of Science, vol. 92 (1996), pp.117–121.
Collections and sustainable development The World Conservation Union (IUCN) is an international non-governmental organization that facilitates biodiversity conservation and sustainable development projects around the world, such as the 2006 IUCN Pan African Freshwater Biodiversity Assessment. In the southern African section of this project, scientists from SAIAB and elsewhere, in partnership with the IUCN, analysed information about the conservation status of all southern Africa’s freshwater fishes, asking questions such as “How wide is the geographic distribution of a species?” and “What are the anthropogenic threats to it?” SAIAB scientists categorized the 354 freshwater fish species that occur in southern Africa into five categories on the basis of the threat of extinction. The information came mainly from several fish collections, of which the largest and most important were the National Fish Collection housed by SAIAB and the fish collection of the Albany Museum, also in Grahamstown. More than 50 000 fish specimen records were plotted on maps, and validated by scientists with hands-on field experience of where these species are found and the extent to which they may be threatened. This project is a fine example of the value and relevance of natural history collections and their associated information in our rapidly changing world. Consult the freshwater fish results at http://saiab. ru.ac.za/webmap. The results of the whole project will be published in the IUCN 2007 Red List at www.iucnredlist.org.
Quest 3(2) 2007 13
Museum fish collections – some early highlights Ofer Gon describes the pioneering days of South Africa’s largest museum fish collections.
ish are the only vertebrate animals that people harvest almost entirely from the wild, for food and recreation. From the outset, they have been of interest to science and natural history museums, where most South African research on fishes began. The country’s scientific fish collections are relatively young, essentially a 20th-century product. Their rise and fall is closely related to that of the institutions that housed them, the resources available, and individuals that nurtured them. Their history comprises three distinct periods: the birth of collections (19th century), the advent of research (to the end of World War II), and consolidation and modern research (the past 60 years). The cameos presented here highlight three remarkable figures – John D.F. Gilchrist and Keppel H. Barnard in Cape Town and J.L.B. Smith in Grahamstown – who contributed some of the stepping stones in the development of the nation’s fish collections.
fledgling fishing industry was growing, paralleled by developing academic and applied research in marine biology, the popularity of sport fishing – and a new demand for expertise. The growth rate of fish collections increased with interaction between fish scientists (such as Barnard and Smith) and the fishing industry, government biologists and fisheries officers, and anglers. Barnard’s review of the South African marine fish fauna (1925–1927) and the discovery of the first living coelacanth (1938) put South African ichthyology on the international map.
Early days At the beginning, there were no fish collections as such. As natural history museums were set up, they acquired fishes for display, which were curated together with other natural history specimens, but did no active fish collecting or fish research to speak of. Various large and small collections were set up in towns along the coast. The South African Museum (SAM) in Cape Town was founded by government proclamation in 1825. In 1830, the fish component of the natural history collection was reported as having “about ninety specimens, including several of great rarity and interest, particularly in the family of the sharks.” In 1874, it contained 433 specimens, used only for display. In Grahamstown in 1855, four military and civilian doctors founded The Grahamstown Medical-Chirurgical Society, dedicated to scientific research, and established a collection that grew into the Albany Museum. The first mention of fish appeared in its annual report for 1859: a Mr Piers had donated “...a valuable collection of Icthyolites, obtained from a large transported block of sandstone, found in the neighbourhood of Fort Beaufort. This collection will throw great light on the nature of fossil fish in South Africa … as two or three specimens in the collection show nearly entire individuals.”
Getting to know our fishes The period 1895–1945 saw a general shift from displays of fishes in museums to collecting for research. Recognizing the need for aquatic research, government began funding it, but apart from the Albany Museum’s self-trained J.L.B. Smith, no professional ichthyologists worked in museums either as curators or as researchers. In the first half of the 20th century, the country’s
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Images: Courtesy of SAIAB
Top: The Pieter Faure in the 1890s, the first South African fisheries research vessel. Above: The British marine biologist, John Gilchrist, who worked with the material collected by the Pieter Faure and produced the first checklist of the fish fauna of South Africa. The Cape, 1890s Concerns were raised about the lack of fishing regulations and insufficient knowledge of the Cape Colony’s fish resources as interest grew in developing a commercial fishing industry. The
government established the Marine Biological Survey to survey and chart fishing grounds in Cape waters, especially the Agulhas Bank, and purchased the first South African fisheries research vessel, the 176-gross-ton steel-hulled steam trawler Pieter Faure John D.F. Gilchrist In 1896, British marine biologist John Gilchrist was appointed to take charge of the Survey. He also became Honorary Keeper of the Department of Marine Invertebrates at the SAM, where, because there was no separate building for them, the Survey’s collections were housed. The Pieter Faure voyaged beyond Cape waters to the coasts of what are now KwaZulu-Natal and Namibia and, in 1902, Gilchrist produced the first, though preliminary, checklist of the fish fauna (marine and freshwater) of South Africa, including 55 families, 164 genera, and 336 species. The Pieter Faure material was by far the largest component of the collection’s growth during Gilchrist’s tenure at the museum, though public donations and the purchase and exchange played their part. Economic depression followed the second Anglo-Boer War. The Marine Biological Survey closed down in 1907, Gilchrist turned his attention to freshwater fishes, and the museum director, Sclater, assumed that the SAM would inherit the Survey collections. Gilchrist objected. Even after Sclater retired, the dispute continued with his successor, L.A. Péringuey. After the formation of the Union of South Africa in 1910, a new Board of Fisheries (Gilchrist was a member) gained control of the fishing industry from the Department of Agriculture of the old Cape government. The museum laid claim to the Pieter Faure collections, however, and, in the end, the intervention of the Prime Minister and the Minister of the Interior was needed to settle the feud. Transfer of the collections to the museum was finally authorized in September 1910. Keppel H. Barnard British biologist Keppel Barnard replaced Gilchrist in 1911, taking charge of the Pieter Faure material. He needed to consult Gilchrist, who was now at the University of Cape Town, but Péringuey threatened that the newcomer would lose his job were he ever to do so. The university bordered on museum property and, the story goes, Barnard cut an opening in the fence between the two institutions to sneak out and discuss the collections with his predecessor. Barnard became familiar with South Africa’s marine fishes and, at the end of 1912, he started active collecting. After four months in KwaZuluNatal and Mozambique that marked one of his best efforts, he returned with specimens of over 100 species of marine and freshwater fishes. In 1915, he reported that 718 marine fish species were known from South Africa, of which 497 (or
in South Africa 63%) were represented in the SAM collection. In 1917, as he was completing the work on the Pieter Faure collections, Barnard started revising Gilchrist’s checklist of South African marine species, a project that took nearly 10 years to complete. His Monograph of the Marine Fishes of South Africa was the first comprehensive study of these fishes (published by the museum in two parts, in 1925 and 1927, respectively). In 1936, Barnard arranged with Irvin & Johnson, a Cape Town-based commercial trawling company, for their skippers to keep unusual fishes for the museum. Their enthusiasm and cooperation rocketed the number of annual accessions into the thousands for several years. J.L.B. Smith A chemist, employed by Rhodes University in Grahamstown, James L.B. Smith became informally involved in the Albany Museum’s fish collection in the late 1920s. Though not employed there, he was allowed to work at rearranging and naming the marine fishes and collecting material. He asked assistance from Barnard, who became his ‘long-distance’ mentor during much of the 1930s, and by 1937 was a recognized authority on the marine fishes of the Eastern Cape. His big break came at the end of 1938 with the discovery of the coelacanth, which brought him worldwide fame. In the same year, he married Margaret Macdonald. She became his research assistant and fish illustrator, and the valuable collection they gathered on their first expedition to Mozambique made Smith realize that much of South Africa’s east coast species diversity originated from the Western Indian Ocean to the north. He continued collecting, and kept and studied his material in the Albany Museum. In the meantime, the East London Museum had officially opened in 1931. Its cultural and natural history collections and displays included marine animals, but never an active study collection of fishes. Fish specimens received by the museum and not required for display were given to Smith. The East London Museum’s claim to fame was the discovery of the coelacanth. Unusually for that time, the museum had a woman, Marjorie Courtenay-Latimer, as its first full-time paid curator. Full of energy, she made friends with the local commercial fishing companies, especially the East London branch of Irvin & Johnson. She persuaded the officers and crews of the trawlers to keep unusual specimens for her. On one of her routine trips to the harbour, she discovered the fish that changed the history of ichthyology in South Africa. A deckhand took her to a pile of fishes, mostly sharks, where she found a large blue fish she’d never seen before. She sent Smith a sketch of the fish, together with notes, from which he identified the specimen as a coelacanth, an ancient group of fishes previously known only from fossils. News of the capture of the first coelacanth brought instant fame to the East London Museum,
Mozambican mining magnate Hugh Le May to produce the Sea Fishes of Southern Africa, he left chemistry to dedicate himself to ichthyology, and in 1947 Rhodes University appointed him professor and head of a new Department of Ichthyology. After the 1949 publication of Sea Fishes, Smith turned his attention to the Western Indian Ocean north of South Africa, intending to produce a companion volume. For this project, the Smiths undertook seven collecting expeditions, covering the east coast of Africa from Mozambique to Kenya and the Seychelles Islands. Having amassed many thousands of specimens, including numerous unknown species, he stopped collecting in 1956, and proceeded to study the fish and publish the results in the Ichthyological Bulletin series he had set up for the purpose. He was still working on the East African material when he died early in 1968. After his death, Rhodes University did not want the financial responsibility for the collection, and the future of the Department of Ichthyology hung in the balance. Margaret Smith persuaded the university and the CSIR (which paid her salary) to establish the J.L.B. Smith Institute in place of her husband’s department and appoint her as its first director. In 1980, the Institute became a national museum governed by the Department of National Education; in 1999, it became a national facility of the National Research Foundation; at the end of 2001, it was renamed the South African Institute for Aquatic Biodiversity.
The past 60 years
Top: Keppel Barnard, biologist and custodian of the Pieter Faure material, who published the first comprehensive study of South Africa’s marine fishes. Below: J.L.B. Smith, who was associated with the discovery of the first modern coelacanth and whose remarkable fish collection formed the basis for that of the South African Institute for Aquatic Biodiversity today. Courtenay-Latimer, Smith, and South African ichthyology. Acknowledging her importance, Smith named the fish Latimeria chalumnae. Smith’s contribution to ichthyology was recognized by the CSIR (founded in 1945, and the new government agency in charge of research), which made him a research fellow with an annual grant of £800. Having received £5 000 from
With the establishment of the CSIR, science in South Africa was reorganized. Funding became available for museums to enlarge their research staff components, and they could hire experts to conduct studies and manage the collections. For the first time, they employed trained ichthyologists, whose research projects became the main contributors to the growth of fish collections round the country. Establishing a viable, permanent collection is a lengthy process. South Africa’s early fish collections depended on enthusiastic and persistent individual curators and scientists who were not ichthyologists – and often slumped when such individuals left or funding was cut. Eventually, our research fish collections were consolidated and reduced to three: one in Cape Town (in the Iziko Museum) and two in Grahamstown (in the South African Institute for Aquatic Biodiversity and the Albany Museum). As a national facility, the future of the SAIAB collection is assured, but with post-1994 demotion of the Albany Museum to provincial level, the continuation of its collection may come under scrutiny when the present curator retires. ■ Dr Ofer Gon is a senior aquatic biologist at SAIAB. He studied in Israel, and worked there and in the USA before joining the Institute in 1982. His research interests include marine fish systematics and the history of ichthyology in South Africa.
Quest 3(2) 2007 15
Q Measuring up Sea level When we measure the height of mountains, we measure from a constant reference called sea level. But sea level is not a constant. Different scientific disciplines use different reference points, such as the average of high tides, or the geoid (the surface of an unmoving global ocean). Another variable is that large masses such as underwater mountains pull water towards them and create a dome effect on the ocean’s surface. (Gene Mascoli, ScienceIQ.com)
angles, and distances between these locations, geodesists create a spatial reference system that everyone can use. Building roads and bridges, conducting land surveys, and making maps are some of the important activities that depend on a spatial reference system. (US National Oceanic & Atmospheric Administration)
We often hear claims like “people only use x% of their brains”. But it’s not possible to quantify the brain’s capacities. Positron emission tomography scans show that most of the brain is active during almost all human activities. (Kenneth A. Wesson, ScienceIQ.com)
The plant with the world’s largest flower – a metre across and weighing up to about 6 kg – evolved from a family of plants whose blossoms are nearly all tiny. Botanists undertook a genetic analysis of Rafflesia arnoldii and found that, over about 46 million years, its flowers had evolved at an accelerated pace. Then, after increasing in size by about 79 times, they slowed down. If humans had evolved in the same way, an average person would be about 146 metres tall. (Science Daily, 12 January 2007)
Earth’s bullet hole
To measure blood pressure, which is caused by the heart’s pumping action, we determine how hard the blood is pushing against the artery walls at two different times: when the heart contracts, called systole; and when the heart relaxes, called diastole.
The hole in the ozone layer over the Antarctic was at its largest in September 2006: 18.24 million square kilometres (bigger even than North America). In some parts of the stratosphere there was almost no ozone at all. We need the ozone to block dangerous ultraviolet light from reaching the Earth. (WhyFiles.org)
Geodesy Geodesy is the science of measuring and monitoring the size and shape of the Earth. Geodesists basically assign addresses to points all over the Earth. By looking at the height,
Measures of minerals The South African Code for Reporting of Mineral Resources and Mineral Reserves sets out minimum standards, recommendations, and
guidelines for public reporting of exploration results, mineral resources, and mineral reserves in South Africa. ■ A mineral resource is a concentration (or occurrence) of material of economic interest in or on the Earth’s crust in such form, quality, and quantity that there are reasonable and realistic prospects for eventual economic extraction. ■ An inferred mineral resource is that part of a mineral resource for which tonnage, grade, and mineral content can be estimated with a low level of confidence. ■ An indicated mineral resource can be estimated with a reasonable level of confidence. It is based on exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings, and drill holes. ■ A measured mineral resource is based on detailed and reliable exploration, sampling, and testing. ■ A mineral reserve is the economically mineable material derived from a measured and/or indicated mineral resource. It is inclusive of diluting materials and allows for losses that may occur when the material is mined. Mineral reserves are subdivided in order of increasing confidence into probable and proved mineral reserves. (Source: Impala Platinum) Compiled by Ceridwen
Q News Norway’s ‘doomsday’ seed bank In February 2007, the Norwegian government announced its design for the Svalbard International Seed Vault, which will house duplicate seeds for almost all the world’s estimated 1.5 million crop strains to protect them from war and climate change. With construction expected to be completed in September this year, seed deliveries are scheduled to begin in March 2008. This US$5-million cold storage unit will be set at the end of a 120-m tunnel cut into the freezing rock inside an Arctic mountain, where the natural temperature is –6 °C. It will be further cooled to –18 °C, and “will offer the best conditions for seed storage on Earth”, according to Cary Fowler, head of the Global Crop Diversity Trust, which will cover the facility’s $125 000 annual operating costs. As protection against global warming, it will be set 130 m up the mountainside, and is expected to survive even the most catastrophic projected rises in sea level. Most seeds are unable to germinate after 20 years or so, so they must be regularly grown into plants and new generations of seeds produced. But, says Fowler, the vault will act as a ‘global insurance policy’ in case banks elsewhere are destroyed by local disasters. In future, it will be possible to replace seeds lost in calamities such as Typhoon Durian, which washed away samples in Jakarta, Indonesia, or in looting, as occurred in Iraq and Afghanistan. Source: Nature, vol. 445 (15 February 2007).
Mafia boss caught by DNA When the godfather of the Sicilan Mafia, Salvatore Riina, was arrested in 1993, Bernardo Provenzano, his right-hand man, took over. He never used a telephone – communicating instead by means of tiny typed notes passed through secret relays – and fostered rumours that he was dead. The prosecutor most responsible for Riina’s arrest, Giovanni Falcone, was murdered in 1992 and Provenzano implicated in the crime. Pietro Grasso
– now Italy’s national prosecutor against organized crime – vowed to find Falcone’s killers. But all he had was a photograph of Provenzano taken in 1959 and a computer-generated ‘identikit’ of what he might look like now. It seemed a dead end. Then, in 2005, Grasso called on Guideppe Novelli for help. Novelli, head of the medical genetics lab at Tor Vergata University in Rome, was perplexed - “How can you identify someone you have no information about?” he asked. But Grasso had a lead from a Mafia informant arrested in 2005, who said that in 2002 Provenzano had gone to Marseilles in France under a false name to be treated for a prostate tumour. A police raid at the clinic found a case history for a man named Gaspare Troia, who had never been admitted to the hospital. His description matched Provenzano’s. Novelli extracted DNA from hospital tissue samples and ran a DNA profile of both mitochondrial and Y-chromosome DNA. He then compared the DNA with that taken from blood samples of Provenzano’s brother, which had been stored in a Palermo hospital where he had undergone surgery. The results showed that they shared the same mother and father: they were brothers. Certain now that Provenzano was alive, the investigators focused their attention on the people who had helped Provenzano make his trip to Marseilles. Finally, by tracking a packet of laundry sent by his wife, police captured their man in an isolated farm house just a couple of kilometres from his birthplace in Corleone. At the hideout, DNA was collected from false teeth, glasses, and an electric razor to confirm Provenzano’s identity. He was convicted and sentenced to life imprisonment for his involvement in the bombings that killed Falcone and another prosecutor in 1992. He now faces further trials on other charges of murder and blackmail. Grasso had at last fulfilled the promise he’d made on the grave of Falcone to capture those responsible for his death. Novelli – and DNA – had triumphed. Source: Nature, vol. 445 (22 February 2007).
Quest 3(2) 2007 17
Alan G. Morris describes the dating of the Hofmeyr skull and its implications for understanding better the evolution of anatomically modern humans.
Human origins & the African connection I
n January 2007, a paper published in Science, gave the age of a nearly complete human skull that had been found half a century ago in a dry channel bed of the Vlekpoort River, near Hofmeyr in the Eastern Cape. The dating of this cranium1 to 36 000 years ago has given us a glimpse into the life and times of the people of sub-Saharan Africa at a critical juncture in human history – and it provides further evidence that this part of the world may indeed be ‘the cradle of humankind’. The discovery of the Hofmeyr skull was due to chance rather than the fruit of a systemic scientific investigation. First noticed during the construction of an anti-erosion weir in the 1950s, the skull was given in 1956 to Marjorie CourtenayLatimer of the East London Museum. She brought it to the attention of Raymond Dart in 1961. At the time, he was deeply focused on the study of the newly discovered australopithecine and early Homo remains from Makapansgat and Olduvai Gorge, and did not recognize the importance of the new specimen. An attempt at dating the skull using radiocarbon failed as there was too little carbon-14 left in the mineralized bone. All that could be said was that the skull was older than 3 000 years.
The skull was returned to the East London Museum, but some of the face and back of the cranium were damaged in transit. With the specimen broken, its dating impossible, and the archaeological context unknown, researchers lost interest. It was transferred to the Port Elizabeth Museum, where Francis Thackeray of the Transvaal Museum noticed it and told me about it in 1990. Working with Isabelle Ribot, and using complex statistical techniques, we began to re-examine the shape of the skull, but without the context that a dating would give we remained uncertain about its importance. Fred Grine of the State University of New York at Stony Brook joined us and suggested that it might be possible to use optically stimulated luminescence to date the last exposure to sunlight of the mud filling the inside of the cranium. Working in a photographic dark room, he carefully extracted a sample of the hardened mud and submitted the sample to Richard Bailey of the University of Oxford, whose team analysed the specimen and provided us with the date. Fred brought Katrina Harvati into the study to add the new ‘morphometric’ statistical approach to our analysis. The luminescence date of 36 000 years ago means that the Hofmeyr
1. Cranium (from the Greek kranion, meaning skull) refers in particular to that part of the skull that encloses the brain.
18 Quest 3(2) 2007
Above: The Hofmeyr skull, right lateral view.
specimen is the only reasonably complete human skull from sub-Saharan Africa recovered from the period between 20 000 and 70 000+ years ago. We tend to think of human evolution in terms of australopithecines and the origin and development of the human line, but actually modern human anatomy and behaviour is a relatively recent event in history, and the Hofmeyr cranium is important for this reason. The geneticists tell us, from the analysis of the genes of living humans, that everyone living on the planet today shares an ancestor somewhere around 150 000 years ago. Their search through the non-coding mitochondrial DNA and Y-chromosome record of living humans has also told us that the living people with the greatest variability – and therefore time depth – are the sub-Saharan Africans. The same data tell us that humans outside Africa went through a ‘bottleneck’ in their genetics perhaps 70 000 years ago, that is to say, their population numbers were greatly reduced for a time. Putting all this together, the geneticists
Images courtesy of A.G. Morris, unless otherwise specified.
Opposite page (left): Map indicating the location of the Hofmeyr discovery. Image: courtesy of Fred Grine. Opposite page (right): Erosion gulleys in the Klipdrift River upstream from the Hofmeyr site in January 2005. This is what the original site may have looked like in the 1950s. Left: The anti-erosion weir in the Klipdrift River in 1992 at the location where the Hofmeyr skull was discovered. Erosion controls installed in the 1950s have been successful and the actual site of discovery is now buried by six metres of stabilized sediment.
have presented us with a model of modern human origins in Africa going further back than 100 000 years ago, with migration out of Africa some time between 50 000 and 70 000 years ago, and a complete replacement of all earlier forms of humanity elsewhere in the world by a small number of these migrating Africans in the subsequent millennia. This genetics model, first proposed in the late 1980s and expanded in the 1990s, has triggered a wide-ranging debate among the palaeoanthropologists who deal with the fossil record. Not all the data fit neatly into the proposed theory, especially those from East Asia, but the one place where the model seems to fit very well is Europe. The Neanderthal aborigines of Europe inhabited their mountainous valleys and associated plains from the Mediterranean to as far north as Britain, Germany, and southern Russia for over 100 000 years. Then, starting somewhere between 40 000 and 50 000 years ago, they began to disappear, to be replaced by newcomers with modern anatomies and behaviours. By 35 000 years ago, the process was nearly complete and only a few scattered Neanderthal bands remained in the Pyrenees and northern Spain and Portugal. They, too, were gone by 30 000 years ago. Surprisingly, although we have quite a few human skeletons of these early new Europeans, especially from the period 25 000–35 000 years ago, we have been unable to locate their African brethren from the same time. From where in Africa did these migrating early Europeans come? We know that the first Europeans had long-limbed African body-builds, but their cranial features were not really like any
modern group of Africans we know today. What was happening in the motherland? Were Africans of three hundred centuries ago different from their descendants living now? We know from the geneticists that the KhoeSan people in particular have mitochondrial DNA variability suggesting that their ancestors lived in the region for at least 100 000 years, but what did these people physically look like in the past? Is KhoeSan morphology as ancient as their genes? The dating of the Hofmeyr skull allowed us to answer some of these questions. Complex multivariate statistics and morphometric analysis of the evidence confirm what we see with our own eyes as we look at the skull: Hofmeyr looks surprisingly like the contemporaneous Europeans. The simplest explanation of this similarity is that African populations at
Graph of multivariate factor analysis showing that the Hofmeyr skull fits well within the range of the Upper Palaeolithic Europeans and falls at the margin of the variation of modern populations. Factor 1 includes upper facial height, nasal height, and maximum frontal breadth; while Factor 2 uses orbital height and maximum cranial length. The populations indicated on the graph are: Upper Palaeolithic Europeans (EUP), KhoeSan (SAN), sub-Saharan Africans (AFR), and Modern Western Eurasians (WEU). Graph: courtesy of Isabelle Ribot
the beginning of the Later Stone Age (30 000–50 000 years ago) were much more robust and larger than their descendants. The African groups that spread out into Europe around that time shared features of marked superciliary (above the eyebrow) development, wide faces, and large teeth. Although fully modern in the tell-tale signs of lack of supra-orbital torus (a Neanderthal-like bony shelf above the eyes), rounded cranium, and canine fosse (depressions in the lower face below the cheek-bones), they had not yet taken on features that characterize modern Africans. These must have come later through a combination of natural selection, sexual selection, and genetic drift. We know that the ‘racial’ characters are well entrenched by 10 000 years ago, so Hofmeyr is telling us to look into the period 30 000–15 000 years ago for evidence of that process. The analysis of the shape and structure of the Hofmeyr skull indicates a result that is consistent with the hypothesis that Upper Palaeolithic Europeans were descended from a population that emigrated from sub-Saharan Africa around 40 000–50 000 years ago. The Hofmeyr specimen also provides an important clue to the critical period in African pre-history at the very beginnings of the modern variation. Now that we have been able to fix the period of this individual in time, Hofmeyr has become a key to understanding the most recent formative stage in human evolution – the rise of modern populations and their regional variability. ■ Professor Morris is in the Department of Human Biology, University of Cape Town. He has published extensively on the origin of anatomically modern humans, and on the Later Stone Age, Iron Age, and historic populations of southern Africa. For the scientific details of the dating of the Hofmeyr skull, consult F.E. Grine, R.M Bailey, K. Havarti, R.P. Nathan, A.G. Morris, G.M. Henderson, I. Ribot, and A.W.G. Pike, “Late Pleistocene Human Skull from Hofmeyr, South Africa, and Modern Human Origins”, in Science, vol. 315 (2007), pp. 226–229.
Quest 3(2) 2007 19
FOR A CAREER IN ENGINEERING, SCIENCE AND THE BUILT ENVIRONMENT, ENTER THE DURBAN UNIVERSITY OF TECHNOLOGY (DUT)
engineering, science and the built environment
The Durban Institute of Technology has changed its name to Durban University of Technology (DUT). The impetus on the name change was to align the vision and mission of the institution, which identifies DUT as “a leading university of technology in Africa that nurtures holistic education and the advancement of knowledge.” DUT offers a wide range of full-time and part-time programmes leading to a variety of tertiary qualifications. These range from certificate courses (one year full-time study) and National Diplomas (three years of full-time study), to Bachelors, Masters and Doctorates in Technology degrees. Qualifications offered by the Faculty: Analytical Chemistry (National Diploma, B.Tech, M.Tech, D.Tech:Chemistry) Analytical Chemists conduct critical analyses in various industries ranging from petroleum, mining, pharmaceutical, paints, plastics, etc., and may be involved at levels from routine analytical technicians to high profile management positions. This programme will provide learners with the necessary knowledge, skills and attitude to perform routine and special chemical analyses. Entry Requirements: A Senior Certificate with Mathematics, Physical Science HG- D or SG- B. Closing Date: 31 October. Enquiries: (031) 2042300. Architectural Technology (National Diploma, B.Tech.) The architectural technician produces drawings, usually on computer, with both broad and detailed aspects of buildings from which contractors build projects. Entry Requirements: A Senior Certificate or equivalent qualification. All applicants are required to attend an Introduction and Selection Programme, which is held annually at the beginning of the year. You will be required to produce a portfolio which may include drawings, sketches, paintings, photographic work, handmade objects or any form of creative work. Closing Date: 31 October. Enquiries:(031) 2042580. Biotechnology (National Diploma, B.Tech., M.Tech., D.Tech) Biotechnology is the application of living organisms or the individual cellular components of these organisms for commercial purposes or environmental control. A person working in the filed of biotechnology will have to have a working knowledge of disciplines such as biochemistry, microbiology, process technology and molecular biology. Graduates are employed in food, pharmaceutical, water and waste water, agriculture, pulp and paper and forestry industries, parastatal organizations, research and academic institutions. Research: The department has state of the art research equipment and well qualified staff with relevant expertise to offer research projects from B.Tech. to Doctoral level in Enzyme Technology, Plant Biotechnology and Water and Wastewater Technology. Entry Requirements: A Senior Certificate or equivalent qualification. Preference will be given to applicants who have passed English, Mathematics, Physical Science and Biology (HG-D or SG-B). Closing Date: 31 October. Enquiries: (031) 3085321. Building (National Diploma) (B.Tech., M.Tech., D.Tech. Construction Management and Quantity Surveying) The National Certificate Building provides a general education in building to a level of supervisor in the housing or similar scale sector. The certificate is issued, on application, after successful completion of Year One. The National Higher Certificate Building provides more advanced education in the above sector and also includes an experiential learning component.
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Issued, on application, after successful completion of Year Two. The National Diploma Building instructional programme is aimed at providing a higher-level general education in construction management and quantity surveying, particularly in the multi-storey and industrial sectors. Issued, on application, after successful completion of Year Three. Entry Requirements: A Senior Certificate with Mathematics HG-E or SG-C or N3 Mathematics (40% or higher). Preference will be given to applicants who have also passed Physical Science and Technical Drawing. Closing Dates: 31 October (Diplomas); 15 November (Degrees). Enquiries: (031) 2042143. Clothing Management (National Diploma, B.Tech., M.Tech) These qualifications are designed to prepare individuals for a wide range of specialist career opportunities in the Clothing and related industries. Entry Requirements: A Senior Certificate or equivalent qualification. Preference will be given to applicants who have also passed Mathematics or Business Economics or Accounting. Proficiency in English is essential. Applicants will also write an Industry accepted numeracy and literacy assessment to determine potential. Closing Date: 31 October. Enquiries : (031) 2042634 Engineering: Chemical (National Diploma, B.Tech., M.Tech., D.Tech.) A chemical engineer is employed in chemical plants for the purposes of research, economic evaluation, chemical engineering design, project management, equipment manufacturing and product marketing. Entry Requirements: A Matriculation Endorsement with Mathematics and Physical Science (HG-C or SG-A). A pass in Technical Drawing and/or Computer Studies will be an added advantage. A pass in English or a National Technical Certificate (N4) with 4 appropriate subjects including Mathematics at 50% or higher and compliance with the language requirements is recommended. Closing Date: 31 October. Enquiries: (031) 2042218 Engineering: Civil (National Diploma, B.Tech., M.Tech., D.Tech) (National Diploma also available at the Indumiso Campus in Pietermaritzburg) Most Civil Engineering Technicians and Technologists are employed in Building Industry or the Civil Engineering Industry, and may be involved in planning, designing or constructing. Within each of these areas, Technicians and Engineers may be employed either in Consulting offices, for a local authority or for a contractor. Entry Requirements: A Senior Certificate or equivalent qualification with Mathematics and Physical Science with a minimum symbol HG-D or SG-B and have passed English or an N4 Certificate with passes in 4 appropriate subjects, including Mathematics and Science (50% or higher) and compliance with the university language requirements. Closing Date: 31 October. Enquiries: (031) 2042224 or Pietermaritzburg (033) 8458827. Engineering: Computer Systems (National Diploma) To provide a foundation in both hardware and software and prepare students for a career demanding specialist knowledge of Computer Programming, Electrical Engineering, Systems Analysis and Management Skills; To cover the relevant aspects of Computer Hardware and Software Engineering, Electronics, Signal and Systems Analysis and other engineering fundamentals; Entry Requirements: Senior Certificate with passes in Mathematics and Physical Science at HG-D or SG-B and have passed English or an N4 certificate with 4 appropriate subjects including Mathematics and Electro Technics at 50% or higher and compliance with the language requirements of the university. Closing date: 31 October. Enquiries: (031) 2042067. Engineering: Electronic (Light Current) (National Diploma: B.Tech., M.Tech., D.Tech.) Electronic Engineering Technicians are employed in specialist fields such as process instrumentation and control, communication engineering, computer systems, power electronics, medical instrumentation, avionics etc. Entry Requirements: A Senior Certificate with passes in Mathematics and Physical Science (HG-D or SG-B) and have passed English and Electro Technics, or an (N4) Certificate with passes at 50% or higher in 4 appropriate subjects including Mathematics and Electro Technics and compliance with the language requirements of the university. Closing Date: 31 October. Enquiries:(031) 2042067/2042072.
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engineering, science and the built environment
Engineering: Electrical (Power Engineering) (National Diploma, B.Tech., M.Tech., D.Tech) (Also available on the Indumiso Campus in Pietermaritzburg) This career is related to the generation and distribution of electricity for power, heat and light. The technician in this field is concerned with designing, developing, installing, faultfinding and testing of electrical motors, generators, alternators, transformers, transmission lines, cables and switchgear. Entry Requirements: A Senior Certificate with Mathematics, Physical Science HG-D or SG-B and have passed English or an N4 Certificate with passes at 50% or higher in 4 relevant subjects including Mathematics and Electro Technics and compliance with the language requirements of the university. Closing Date: 31 October. Enquiries: (031) 2042062. Indumiso: (033) 8458827. Engineering: Industrial (National Diploma, B.Tech., M.Tech., D.Tech.) The Industrial Engineer is trained in a wide field, which includes Economics, Management, Engineering and Science. The Industrial Engineer was primarily dominant in the manufacturing sector and has now found positions in hospitals, banks, consulting companies, government departments and in the field of information technology. Entry Requirements: A Senior Certificate or equivalent qualification with passes in Mathematics, Physical Science with HG-D or SG-B. English must be passed. Recommended subjects: Technical Drawing, Computer Studies, Electro Technics, Accounting and Mechano Technics or an N4 certificate with passes of 50% or higher in 4 appropriate subjects, two of which must include Mathematics and Science and compliance with the language requirements of the university. Closing Date: 31 October. Enquiries:(031) 2042445. Engineering: Mechanical (National Diploma, B.Tech., M.Tech., D.Tech) Mechanical Engineering is the most general of all industry-based occupations, ranging across every stage of the manufacturing process from design, draughting and assembly to quality control, plant operation, maintenance and management. Entry Requirements: A Senior Certificate or equivalent qualification with passes in Mathematics, Physical Science HG-D or SG-B, and a pass in English. An interview may also be required or an N4 certificate with passes of 50% or higher in 4 appropriate subjects, two of which must include Mathematics and Mechano Technics and compliance with the language requirements as stated in the General Rules. Closing Date: 31 October. Enquiries:(031) 2042115. Food Technology (National Diploma, B.Tech., M.Tech., D.Tech) Food Technologists are responsible for maintaining and improving the quality of processed food in the food and beverage industry. The industry is highly diversified and embraces sectors such as dairy, meat, fish, poultry, cereals, confectionary, canned and frozen products and a vast number of fast moving consumer goods. Food Technologists continually strive to make better use of food resources and to find more efficient mass-production methods while maintaining the highest level of quality control. Food Technologists may eventually specialize in one of the following areas: Quality Assurance/Quality Control; Product Research & Development; Production/Management. As there is presently a shortage of well-qualified Food Technologists, promotion opportunities to supervisory or management positions are good, provided students are prepared to work hard, possess leadership ability and are willing to study further. Entry Requirements: A Senior Certificate or equivalent qualification. Preference will be given to applicants who have passed English, Mathematics, Physical Science and Biology HG-D or SG-B. Closing Date: 31 October. Enquiries: (031) 308-6769.
Horticulture (National Diploma) A rapidly growing field of agriculture. Horticulture includes producing, processing and marketing of fruits, vegetables and ornamental plants (turf grass, flowers, shrubs and trees grown and used for their beauty). Entry Requirements: A Senior Certificate or equivalent qualification with a minimum of English HG-E or SG-D or English assessment test. Preference will be given to those applicants who have had practical experience with a reputable horticultural concern or who have an agricultural or horticultural background. Biology or Physical Science at HG is highly recommended. Closing Date: 31 October. Enquiries: (031) 3085124. Landscape Technology (National Diploma) Landscape Technologists practice the art of design as they plan aesthetically appealing landscapes that are pleasing to their clients. They must know plant species and plant materials to develop plans that are attractive yet functional in their environment. Entry Requirements: A Senior Certificate or equivalent qualification with a minimum of English HG-E or SG-D or English proficiency test. Art or Technical Drawing is pre-requisite subjects. Preference will also be given to applicants who have studied biology and/or Physical Science. Closing Date: 31 October. Enquiries: (031) 3085124. Maritime Studies (National Diploma) Maritime Studies is aimed at people who wish to gain the knowledge and skills required for a successful career in shipping and allied industries. For example, shipping companies, shipbrokers and charterers, ship surveyors, warehousing and storage, ships' agencies and Portnet. Entry Requirements: A Senior Certificate or equivalent qualification, with Mathematics SG-C. Preference will be given to applicants who have also passed Physical Science at Senior Certificate Level and English and according to the results of psychometric testing, a short interview and employment status. Closing Date: 31 October. Enquiries: (031) 2042144. Pulp and Paper Technology (B.Tech.) This programme comprises both theoretical and research components and is normally offered by distance learning methods only. Occasionally, if numbers warrant it, the programme will be offered full-time at the University. Entry Requirements: A National Diploma in Engineering or Science or University degree in Engineering or Science or an N6 Diploma in Pulp or Paper. Prospective students with other qualifications should contact the Head of Department. Closing Date: 31 October. Enquiries: (031) 2042123. Surveying (National Diploma, B.Tech., M.Tech., D.Tech.) Surveying Technicians are involved in planning and construction within the civil/building industry. Surveying is the means of representing the layout of the land accurately on maps or plans, and to indicate the exact position of any structure or other man-made or natural object on, above or below the ground. Entry Requirements: A Senior Certificate or equivalent qualification, with passes in Mathematics and Physical Science with a minimum symbol HG-D or SG-B, or the equivalent thereof and have passed English or an N4 Certificate. Closing Date: 31 October. Enquiries: (031) 2042224. Textile Technology (National Diploma) Textile Technologists are involved in textile production, fabric development, marketing and quality control in textile and associated industries (chemical and machinery suppliers fashion retailers). Textile Technology is concerned with the manufacture of fabrics but covers the entire spectrum from raw materials (both natural and synthetic) through various yarn and fabric manufacturing routes to the dyeing and finishing of fabrics. Apparel, household and industrial fabrics are studied in detail from production, technical and construction aspects. Entry Requirements: A Senior Certificate or equivalent qualification, which includes passes in Mathematics and Physical Science with minimum symbols HG-E or SG-D and English. All students will write the departmental entrance test. Closing Date: 31 October. Enquiries: (031) 2042148. Town and Regional Planning (National Diploma, B.Tech.) The work of a Town and Regional Planning Technician is of a diverse nature and embraces inter alia: surveying tasks, planning surveys, the analysis and presentation of data by means of maps, graphs, diagrams and sketches, assistance in the preparation of town planning schemes and the construction of scale models for proposed schemes, and the use of technologies such as Computer Aided Draughting (CAD) and Geographic Information Systems (GIS). Entry Requirements: A National Senior Certificate or recognised equivalent qualification. Compulsory subjects for entry to the course are: English HG-D or SG-C, Mathematics HG-E or SG-D and Geography HG-D or SG-C. Recommended subjects are: History, Technical Drawing and Biology. Applicants are required to undergo an interview and selection test. Closing Date: 30 September. Enquiries: (031) 2042673.
Further Information: Student Admissions, P O Box 1334, DURBAN, 4000 Tel: +27(0)31 204-2111/2526/2473 or Pietermaritzburg Campus on +27(0)33 845-8800 Call Centre: 0860 10 31 94, Email: email@example.com, Website: www.dut.ac.za 2007 © DS@DUT 22-02-07
PLUTO – when is a planet a planet? Case Rijsdijk of the South African Astronomical Observatory explains why planets have had to be redefined. Images: The International Astronomical Union (Martin Kommesser). In the artist’s impressions reproduced here, the celestial bodies are drawn to scale, but without correct relative distances.
Above: At the meeting of the General Assembly of the International Astronomical Union (IAU) in Prague, 14–25 August 2006, new planetary definitions were drawn up, reducing the number of planets to eight and reclassifying Pluto as a dwarf planet. This artist’s impression illustrates the new configuration (with the Sun on the left).
The Titius-Bode relation This relation, or numerical sequence, was first proposed in 1766 by the German mathematician Johann Daniel Titius (1729–1796) and announced by J. E. Bode in 1772. The sequence corresponds to the distances from the Sun of the six planets known at that time. Such distances are now calculated in astronomical units (AU), where 1 AU is the mean distance from the Earth to the Sun (that is, 150 million km). The original series of numbers was obtained by using 0 as the first, followed by 3, and then doubled, to give 0, 3, 6, 12 …. Then 4 was added to each number, and the final sequence obtained by dividing the numbers by 10 to give the Titius–Bode relation, namely: 0.4, 0.7, 1.0, 1.6 …. Mathematically, this sequence can be described by the relationship D = [A + B (2n)]/10, where D = distance; A = 4; B = 3; and n = –∞, 0, 1, 2, …. Planet Mercury Venus Earth Mars (Ceres) Jupiter Saturn Uranus Neptune Pluto
Titius-Bode mean distance 0.4 0.7 1.0 1.6 2.8 5.2 10.0 19.6 38.8 77.2
Actual distance in AU 0.39 0.72 1.0 1.52 2.77 5.20 9.54 19.18 30.06 39.44
The sequence breaks down after Uranus, but it worked well before the discovery of Neptune. When Giuseppe Piazzi discovered Ceres in 1801, he initially thought it was a planet because it was at the place where he expected to find one. Subsequently, Ceres was found to be a large asteroid.
24 Quest 3(2) 2007
housands of years ago, observers of the night sky recognized that nearly all the points of light they saw appeared to be fixed relative to each other. But some moved relative to those that were fixed, and they were called planets (from the Greek word, planetes, meaning ‘wanderer’). Five were visible to the naked eye so that, with the Sun and the Moon, there were seven celestial objects moving across the sky relative to the background stars – these gave us our seven-day week. In time, better explanations of the motion of the planets were developed by Hipparcus, Ptolemy, Brahe, Copernicus, Kepler, and others. The view of the Solar System as geocentric (Earth-centred), with planetary motions driven by a complex system of epicycles, was replaced by the simpler heliocentric (Sun-centred) Keplerian model1, in which the planets moved in elliptical, but almost circular, orbits around the Sun: any object that did so was considered to be a planet. In 1781, William Herschel (father of John Herschel, who worked in South Africa from 1833–1838) discovered a new planet, later named Uranus, at the distance indicated by the Titius–Bode relation. Calculations by the French celestial mechanician Urbain Jean Le Verrier predicted the position of a planet further away, which allowed the German astronomer Johann Gottfried Galle to locate Neptune in 1846. In the meantime, Giuseppe Piazzi had argued that there should be a planet between Mars and
1. The German astronomer, Johan Kepler (1571–1630), published three laws of planetary motion between 1609 and 1619. As discoverer of these laws, he is regarded as one of the founders of modern astronomy.
The Kuiper Belt and the Oort Cloud
Above: Artist’s impression of a proposal to the world’s astronomers in 2006 to redefine the lower end of the planetary scale in such a way that the Solar System would comprise 12 planets, including Ceres, Pluto, Charon, and 2003 UB313. This proposal was rejected.
and subsequently many more. These were large planets, several times more massive than Jupiter. As technology improved, new techniques were used and many exoplanets were discovered. Several questions arose. Were these just large planets or brown dwarfs (that is, objects whose mass was too low for a star)? What size did an object orbiting a distant star have to be for the two to be considered a star and a planet, or a double star (that is, a binary)? What dividing lines separated these different kinds of object? The problem was compounded with the discovery of objects with the mass of a planet that ‘floated’ freely in space without orbiting a central star. Technology marched on. Using a newly developed technique known as ‘gravitational microlensing’, a large international collaboration that included South African astronomers discovered an Earth-sized planet in 20053, which Below: A dozen ‘candidate planets’ on the IAU’s planetary ‘watchlist’, which keeps changing as new objects are found and the physics of the existing candidates becomes better known.
Jupiter. On 1 January 1801, he (accidentally) discovered an object at the right place. Later called Ceres, it was very small and initially thought to be the ‘missing’ planet. A year later, another (even smaller) object, Pallas, was discovered in more or less the same orbit around the Sun as Ceres. William Herschel argued that there could not be two planets in the same orbit around the Sun, as each planet had an orbit of its own: neither Ceres nor Pallas could therefore be planets and they were ‘demoted’ to being asteroids2. Since then, many other asteroids have been discovered, mainly in the zone between the orbits of Mars and Jupiter known as the Asteroid Belt. Asteroids are still being discovered and many thousands have been named, numbered, and classified. In 1930, the American astronomer Clyde Tombaugh discovered Pluto and, after that, the Solar System was said to consist of nine planets. Since then, improved technology and larger telescopes have revealed more details. Comets, asteroids, and additional moons around the planets were found. In 1978, for example, came the discovery of Pluto’s moon, Charon, and, in 2005, of two further small moons (Nix and Hydra). The giant planet Jupiter is now known to have more than 60 moons. Several telescopes around the Earth are dedicated to discovering Near Earth Objects, which are asteroids whose orbits could cross that of Earth and make an impact possible: to date, none has been found that will collide with the Earth in the foreseeable future.
The Kuiper Belt, named after its discoverer Gerard Kuiper, is a disk of asteroid-like objects around the Solar System beyond the orbit of Pluto. Like the Asteroid Belt between Mars and Jupiter, it is home to many large and small asteroids, small rocks, dust, and gas that are thought to be the remnants of the formation of the Solar System. Many short-period comets (with periods lasting 200 years or less) come from this region. The Oort Cloud is an enormous cloud of material surrounding the Kuiper Belt, stretching almost halfway to the nearest stars. First described by Jan Oort in 1950, it is home to billions of icy objects and comets. Passing stars occasionally disturb regions of it, affecting some of these bodies. They then ‘fall’ towards the Sun (because it is the most massive object in the Solar System) and appear to us as comets*, such as Kahoutek 1974 and, more recently, 1P/McNaught (2007), which were one-off visitors, never to return. Others, such as Halley and Encke, are short-period comets and return every 76 and 3.3 years, respectively. Hyakutake (1995), Hale-Bopp (1996) were long-period comets with periods of 15 000 and 3 200 years, respectively. * A comet is a small body, composed of ice and dust, in orbit around the Sun. The name comes from the Greek kometes, meaning ‘long-haired’. Many comets are thought to exist beyond the planets. The gravitational influence of passing stars can move them into new orbits that bring them into the inner Solar System, where they become visible from Earth. When it is far from the Sun, a comet’s nucleus is frozen solid and shines only by reflecting sunlight. When the nucleus nears the Sun, it heats up and releases gas (which becomes ionized and emits light) and dust, forming a ‘coma’, or an envelope round the nucleus that is often the shape of a teardrop. Then, in some cases, it forms a tail. The nucleus may be only 1 km or so across, but the coma can extend for 105 km or more from the nucleus, and the tail for 108 km.
The definition problem The problem of how exactly to define a planet started some years ago with the discovery of planets around distant stars (known as extrasolar planets, or ‘exoplanets’) by Michel Mayor working with Didier Queloz and Geoffrey Marcy working with Paul Butler. The former team had discovered a planet in the dust disk around the star called 51 Pegasi. Marcy and Butler went on to discover planets around 47 Ursa Majoris and 70 Virginis, 2. Asteroids are small rocky or metallic objects in the Solar System. Lying mainly in the zone between the orbits of Mars and Jupiter, they range in size from Ceres (nearly 1 000 km in diameter) to less than 10 km for the smallest one found so far. 3. See “Finding extrasolar planets” by John Menzies, in Quest (2006), 2(4), pp. 30–33.
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If the status of Eris caused debate, however, what was to be done about Pluto? In the Solar System, Pluto is different from the other planets. Unlike the others, its orbit is very elliptical4, and every so often comes inside that of Neptune. Furthermore, it was always thought strange that the four rocky planets (Mercury, Venus, Earth, and Mars) were followed by four gas giant planets (Jupiter, Saturn, Uranus, and Neptune) – with tiny rocky Pluto as the anomaly at the end! Other problems arose with the more recent Solar System discoveries. Many of the objects had orbits at high angles of inclination to the ecliptic4. The orbit of Eris, for example, is inclined at 44°. In addition, their orbits were very eccentric5, and some of the new objects had strange shapes: 2003 EL61, for instance, has the shape of a rugby ball. So the overwhelming question now became “What constitutes a planet?” The previous definition, in its simplest terms, was “a nonluminous body that orbited a star, or our Sun, generally round in shape (ball-shaped), and made up of rock or in some cases rock, ice, and gas”. It was clearly becoming inadequate. Size, orbit eccentricity and inclination, and shape had now also to be taken into account.
Above: Artist’s conception of eight dwarf planets. No photographs have yet been made of these objects.
Top: Three celestial bodies in the Solar System that were discussed by the IAU in 2006 as possible candidates for planetary status (with the Earth on the right).
added fuel to the planet debate. Planets were being found around distant stars, but no more new ones at home in our Solar System. More recently, new celestial objects such as Quaour and Sedna were found in the Kuiper Belt and the Oort Cloud, raising further questions about the definition of a Solar System planet. Others, not yet named, were found and identified by their discovery numbers. These include 2003 EL61 and 2005 FY9. They were not considered to be planets, because they lay beyond the orbit of Neptune and were smaller than Pluto, so they were initially classed as ‘trans-Neptunian objects’. In 2005, the American astronomer, Mike Brown, discovered an object larger than Pluto (2003 UB313), which, therefore, could be dubbed the ‘10th planet’. It was officially named Eris by the International Astronomical Union (IAU). Later it was found to have a companion, Dysnomia, which corresponded to other planets and their moons.
Towards a solution It’s hard to change a definition that both scientists and the public have got used to, as there are cultural aspects to be considered. People are accustomed to having nine planets and would happily accept a 10th or even an 11th or 12th, but they were unwilling to lose one! What new definition could embrace not only culture but also the characteristics, circumstances, and cosmogony required by astrophysicists? Characteristics – these are the physical attributes of a planet, such as its temperature, mass, shape, and size. It is generally accepted that a planet does not radiate its own light, but is visible by the reflected light of its central star or Sun; that it is ball-shaped; and that it is smaller and less massive than its central star. But how small can a planet be if it’s to be a planet? If Eris is a planet because it is bigger than Pluto, why should Pluto be the limiting size? Why not Ceres? Circumstances – these are the orbital attributes (that is, the degree of eccentricity of an object’s orbit around the central star or Sun). Some recently discovered exoplanets have orbits so eccentric that they can overlap others. Comets, for example, can have elliptical orbits that cross over the orbits of several planets. Another consideration is the orbit’s inclination: should the planets orbit the central star in a plane, or can any inclination be deemed acceptable? Cosmogony – this is the study of the origin or mode of formation of cosmic systems. The generally accepted model (the Laplacian model) is that our Solar System formed from a cloud of dust and gas out of which a massive hot body, our Sun, condensed at its centre. The remains spun around this central object in a disk, and out of these
4. Most of the planets in the Solar System orbit the Sun in a plane called ‘the ecliptic’. At 17°, Pluto’s orbit has the greatest inclination of any planet to the ecliptic, and is the most elliptical of all the planetary orbits. 5. If a planet‘s orbit has a high angle of inclination, it could mean that it did not form from the primordial dust cloud but that it was ‘captured’ (that is, forced into an orbit round the Sun) by another massive object (such as Jupiter). Should such a “captured” object be called a planet?
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IAU Planetary Resolutions (Prague, August 2006) RESOLUTION 5 – Definition of a Planet in the Solar System Contemporary observations are changing our understanding of planetary systems, and it is important that our nomenclature for objects reflect our current understanding. This applies, in particular, to the designation “planets”. The word “planet” originally described “wanderers” that were known only as moving lights in the sky. Recent discoveries lead us to create a new definition, which we can make using currently available scientific information. The IAU therefore resolves that planets and other bodies, except satellites, in our Solar System be defined into three distinct categories in the following way: (1) A planet1 is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. (2) A “dwarf planet” is a celestial body that: (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape2 (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite. (3) All other objects3 except satellites, orbiting the Sun shall be referred to collectively as “Small Solar System Bodies”. 1. 2. 3.
The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. An IAU process will be established to assign borderline objects into either dwarf planet or other categories. These currently include most of the Solar System asteroids, most trans-Neptunian Objects, comets, and other small bodies.
RESOLUTION 6 – Pluto The IAU further resolves: Pluto is a “dwarf planet” by the above definition and is recognized as the prototype of a new category of Trans-Neptunian Objects1. 1.
An IAU process will be established to select a name for this category.
remains the planets eventually formed, as matter collided and accreted. This means that planets which formed with the Sun would orbit it in the plane that we call ‘the ecliptic’. Should objects that might not have emerged from the primordial dust also be called planets6? Proposing a new definition of a planet is difficult. Once proposed, it has to be approved by astronomy’s official governing body (which, by international agreement, is the IAU). Every three years it has a General Assembly, at which various proposals are presented and put to the vote. The last one, in August 2006 in Prague, formally accepted several proposals on what constitutes a planet in our Solar System. One proposal suggested that Ceres, Pluto’s moon Charon7, and Eris (2003 UB313) all be accepted as planets and that the status of Pluto remain unchanged, which would increase the number of planets to 12. An argument against this proposal was that the number of planets would be constantly increasing as many objects have already been discovered that would need to be assessed to see if they qualified as ‘planets’. Two further proposals, which excluded Pluto as a planet, were voted on and accepted. The definition of a planet now became, in simple terms: ■ an object in orbit around the Sun ■ round in shape ■ the only object in that orbit. This definition eliminates Pluto, which crosses into Neptune’s orbit, so our Solar System is now
officially deemed to have only eight planets8. The future The IAU’s new definition of a planet in our Solar System has not been unanimously accepted. More important, we still lack a general definition to cover all planets – those in the Solar System as well as the exoplanets outside it. Further new discoveries will bring new considerations. If we find that our Solar System is not typical of others, for instance, we might need to change our new definition radically. If small, rocky, Earth-like planets are unusual and large Jupitermass planets far more common, additional terms might be needed. If life is discovered on some distant planet, then an entire subsidiary group of life-sustaining planets is possible. It will be a while before a definition is found that satisfies everyone. I hope, however, that these explanations will give readers greater understanding of the problem and enable them, too, to contribute to the debate. ■ Case Rijsdijk is a consultant on astronomy education at the South African Astronomical Observatory and a researcher in particle physics. For years he has brought astronomy to the public through his articles for the popular press and his SABC radio broadcasts. For more details, consult Bruce Dorminey, Distant Wanderers (Copernicus Books, 2002); John Davies, Beyond Pluto (Cambridge University Press, 2001); and Nigel Hey, Solar System (Weidenfeld and Nicholson, 2002). Visit the following websites: http://saao.ac.za; http://saao.ac.za/assa; www.iau.org; http://skytonight. com; www.eso.org; http://cosmiccontroversy.com
6. The greater the eccentricity, the more ‘egg-shaped’ is the orbit. Most planets have orbits whose eccentricity is hardly noticeable: their orbits are nearly circular. 7. The motivation for classifying Pluto’s moon Charon is the position of the barycentre of the two outside Pluto. The barycentre is the common point around which two gravitationally-bound objects orbit. If they have equal mass, the barycentre lies halfway between them. As the mass of one increases, so the barycentre moves towards the more massive object. If one mass is far greater than the other, the barycentre may actually lie within the body of the larger mass. In the Earth–Moon system, for instance, the barycentre is inside the Earth, which makes this a planet–moon system. In the case of Pluto and Charon, where the barycentre does not lie within Pluto, it is argued that the two make up a double-planet system. 8. A substantial number of the world’s planetary scientists disagree with the IAU’s withdrawal of planetary status from Pluto, and they plan to continue the debate at the next IAU General Assembly in 2009 in Rio de Janeiro.
Q News Photograph of Comet McNaught, taken from Paarden Island, looking over Table Bay towards Kloof Nek, to the right of Table Mountain. Image: Stephen Potter
The Great Comet of 2007 (McNaught) Comets occasionally visit the inner parts of the Solar System, but very bright great comets are rare. Since 1960, ten comets have been visible from Earth with the naked eye, though few qualified as ‘great’. Comet McNaught is the brightest since 1965. Comets have been likened to dirty snowballs, consisting largely of frozen, fluffy water (hence ‘snow’) embedded with dust particles. They reside in the outer Solar System, beyond Pluto’s orbit. Small disturbances to their travel paths, induced by planets, occasionally cause one to deviate towards the Sun, as probably happened to McNaught. When a comet approaches the Sun, the radiant heat begins to evaporate the snow. The water vapour (which also includes other chemicals) drifts away from the comet and is pushed out by the solar wind in a stream of particles, forming a tail. It always points away from the Sun, and can reach lengths as great as many millions of kilometres. But the amount of gas in it is in fact small enough to fit inside a soccer ball. Comets normally revert to the outer Solar System, albeit in an orbit that eventually returns to the Sun. McNaught’s precise trajectory is not known, but current estimates indicate that its orbit may allow it to escape the Sun altogether. This can occur if a comet picked up extra speed, while falling towards the Sun, from coming too close to a planet. If this happened, McNaught will never return, but will leave the Solar System and may eventually (after millions of years) gravitate towards another star. We can expect to see other comets, but it may be decades before one becomes as bright as this. – Stephen Potter, SAAO For more, visit www.saao.ac.za/ public-info/comet-mcnaught/
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News Q Things are hotting up On 2 February, in Paris, France, the Intergovernmental Panel on Climate Change (IPCC) published its fourth assessment report, based on the work of thousands of researchers and compiled and summarized by some 600 scientists. After a year of making sense of the huge amount of data, the Panel concluded that global warming is accelerating. It noted (with over 90% certainty) that recent temperature increases are driven by human activity.
How fast is climate changing? The facts and revised estimates emerging from studies conducted about the speed of change so far are causing concern worldwide. n The previous IPCC estimate in 2001, of 0.6 °C average increase in global temperature for the past century, has now risen to 0.74 °C. n The 10 hottest years on record all postdate 1990 (temperatures were first widely recorded around 1850). n Permanent Arctic sea ice is contracting by 7% every decade. n The sea level, which rose an average of 1.8 mm a year from 1961–2003, went up by an average of 3.1 mm a year between 1993 and 2003. n Carbon dioxide is accumulating in the atmosphere at a record rate, with annual increases now a third greater than 20 years ago. The trends are becoming clearer. n North and South America and northern Europe are getting wetter.
n The Mediterranean region and southern Africa are getting drier. n Weather events have become more extreme – droughts are more intense and longer since the 1970s; rainfall, when it occurs, is heavier because warmer air holds more moisture.
What will happen? Predictions are difficult because more facts are emerging about the mechanisms of change. More factors, therefore, together with their possible interactions, have to be taken into account when looking ahead and it’s harder to be certain how each will affect others. The IPCC report estimates what could happen in various respects with a significant degree of certainty. n In 2001, the IPCC gave the range of predictions of the rise in the temperature by 2100 as 1.4–5.8 °C; the 2007 report has increased the range to 1.1–6.4 °C. Where we find ourselves on this scale depends mainly on how much fossil fuel the world burns. n Hot days will continue getting hotter and more frequent. n Rains will come down more heavily. n The warming will likely deliver an ice-free Arctic and a 30% drop in rainfall in many subtropical regions, including a huge area from the Mediterranean and North Africa through the Middle East to central Asia, and another across southern Africa.
Recent findings The cut-off point of research findings to be included for the IPCC report was the
end of 2005, to allow time to synthesize the material. Notable research continued, however, and some important results have been published during the last year. n Antarctic air – the troposphere above Antarctica has warmed by 0.5–0.7 °C per decade over the past 30 years. n Atlantic hurricanes – rising sea-surface temperatures correlate strongly with the observed increase in the number of category 4 and 5 Atlantic hurricanes between 1970 and 2004 (other factors that affect hurricane formation do not seem to have increased in line with the upward trend). n River runoff – more carbon dioxide in the atmosphere leads to plants losing less water by transpiration, suggests one model. This could affect the amount of fresh water available for human use. n Sea levels – if the rate of sea-level rise is proportional to the global rise in temperature since pre-industrial times, sea levels could rise by up to 1.4 m by 2100. According to Achim Steiner, director of the United Nations Environment Programme: “February 2nd will be remembered as the date when question marks were removed on whether climate change has anything to do with human activity – the moment when attention will shift to what on earth we are going to do about it.” The summary report is available at www.ipcc.ch. Sources: Nature, vol. 445 (8 February 2007); New Scientist, vol. 193 (10 February 2007).
The problem with air travel Air travel is fast, relatively cheap, and efficient, which is why passenger traffic is expected to rise steadily, with freight increasing even faster. Predicted long-term annual growth rates are 5.2% for passengers and 6.2% for cargo. The aviation industry’s continued expansion is set to transform it into one of the largest single contributors to global warming. Aeroplanes have reduced their use of energy, however. The International Air Transport Association (IATA) reports that today’s jet engines are about 40% more efficient than those designed in the 1960s, and pollutants such as soot and sulphur have been almost eliminated from jet exhaust. How does this add up? About 85 000 commercial flights take off each day, and the number is predicted to double by 2050. Further improvements in fuel efficiency are likely to be modest. So there’s a widening disparity between the air industry’s growth of more than 5% a year and the projected improvements in jetliner fuel efficiency, which is closer to 2% a year. Each year, jetliners burn about 130 million tonnes of kerosene, and a flight across the Atlantic can use about 60 000 litres – more fuel than an average motorist needs in 50 years of driving – and
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generate around 140 tonnes of carbon dioxide and 750 kg of NOx gases. At 10 km up, where most airliners fly, NOx creates ozone, which at these heights helps to warm the planet, and water vapour in the exhaust creates contrails that act as seeds for cirrus clouds, reflecting heat back to Earth. The IPCC concludes, therefore, that pollution from high-flying jets is up to four times as damaging to the environment as the same amount released by chimneys and exhaust pipes at ground level. What can an individual do? n Switch from flying to video-conferencing n Pay off-setting companies to plant trees or invest in green-energy projects for your share of a flight’s greenhouse gas emissions. What can others do? n Make air-traffic control more efficient, to reduce aeroplane queues in the air or on the ground (which, according to IATA, could save 12% of their global carbon dioxide emissions) n Tax air travel n Design ‘greener’ planes and research the use of greener fuels. Source: New Scientist, vol. 193 (24 February 2007).
Dangerous times for baby fishes New information from Nadine Strydom reveals the adventurous early life of marine fishes and the dangers they overcome as they grow to adulthood. Knowing about these tiny animals helps us to understand fishes better and to fight the dramatic declines in wild fish populations.
ishes are one of the most important animal groups used as a source of food worldwide, and most of the fish that people eat are caught in the wild. Mainly as a result of over-fishing – but also because of natural environmental change and other human activities – fish stocks everywhere have dropped dramatically. Scientists have tried hard to understand fish populations, but managing fishes in the ocean isn’t easy, for they are not penned like farm animals, so, even when we can see them, they’re difficult to count1. We know that the numbers of fishes in the wild are finite (and decreasing), and the huge impact of people’s fishing activities makes it urgent to find ways to manage marine fish stocks successfully. Fundamental to this effort is the biology of ocean animals – that is, their growth, reproduction, preferred nursery areas, and feeding habits – and the ways in which they relate to their environment (or, their ecology). Knowing the biology and ecology of fishes helps scientists to understand and protect fishes better.
Images: Nadine Strydom (SAIAB) unless otherwise indicated
Top left: Larval fish study-site behind the breakers – this area is called the shallow nearshore. In the background is the Alexandria dune field, Algoa Bay. Top right: A large shoal of juvenile mullet sheltering along the margins of an estuary, out of harm’s way. The shallows provide shelter from large fish predators and strong currents. Right: Larval fish samples in the lab. It takes hours to sort, count, identify, and measure them. Middle right: A sieve containing a catch of larval blacktail from a small rocky bay near Port Alfred. Below: A shoal of larval fishes.
Larvae as a key to conservation Understanding a fish population well enough to manage it properly means understanding the life cycle of the fish, including the earliest stages – the larvae. Much as frogs have a tadpole phase, so, too, most fishes hatch into a larval stage. Unlike tadpoles, however, newly hatched fish larvae are so small that most are invisible to the naked eye.
1. For more on ways in which scientists attempt to count fish and monitor their movements, see the suite of articles, “Still counting” in Quest (2006), 3(1), pp. 24–27 and the box “Exercise markrecapturing to estimate fish numbers” in the same issue, p. 22.
Quest 3(2) 2007 29
Studying larval fishes
■ ■ ■ ■
At the start of their lives, fishes are dispersed into plankton as eggs or larvae. A single type of collecting device, such as a plankton net that varies in shape and size, can be used to sample the larvae of many kinds of fishes at once. In contrast with the sampling of reproductively active adults in an ecosystem, sampling fish larvae is genetically inexpensive. But few descriptions are as yet available to link a larval fish to the adult from which it stems. Scientists in the 1800s thought that larval fishes were SURF ZOOPLANKTON a different species, until they figured out that most fish have a larval phase. The difficulty was that larval fishes look and behave very differently from the juveniles and adults into which they grow. Working on larval fishes means catching things that can’t be seen without a microscope. You have patiently to sort through samples to pick out the baby fishes, and then spend hours counting, measuring, and determining which larvae belong to which adult fish species. This information tells scientists a great deal about the ocean conditions and the habitats in which these larvae can survive. Studies of larval fishes are being conducted around the world for several reasons: to understand the sequence of developmental events from fertilized egg to juvenile fish to understand variation in the life-history styles of fishes to understand larval behaviour, movement, habitat requirements, and sensitivities to estimate how many adults of the species there are in an area based on the number of eggs and larvae found (this required complicated mathematics, and gives data that are important for fisheries managers) to improve aquaculture through greater knowledge of larval morphology (that is, body shape and structure), feeding, and behaviour, and through the description of the larvae of species to provide holistic information about any fish population to understand the ways in which larval fishes can serve as indicators of ecosystem health (many fishes do not breed unless the conditions are favourable), for instance in estuaries, where pollution and upstream dams can affect water quality to improve fish biodiversity assessments in habitats with species that live in hard-to-reach areas, inaccessible to traditional methods for sampling adult fish (such as fishing, netting, or diving) to help systematists and taxonomists understand relatedness among fish species because of the morphological features shared by larvae that belong to the same genus and family of fishes.
Top right: An expedition with typical gear used for plankton-trawling in estuaries. Photograph: Alan Whitfield (SAIAB)
Above right: A specially designed larval fish seine net being pulled through the surf. Photograph: S. Warren (Bayworld)
Top left: Charts showing typical microscopic plants (phytoplankton) and animals (zooplankton) found in temperate surf zones. Larval fishes also form part of this plankton.
The larval phase lasts from days to months depending on the species and environmental conditions. The ocean temperature, for instance, can influence the rate at which a larva develops into a juvenile fish – the warmer the water the speedier the development. The size and sustainability of any fish population is intricately linked to the success of its larval phase, so it’s imperative to find out what’s needed for larval fishes to be able to survive. It also helps to know about the environmental effects (such as those of ocean currents) on this crucial stage in their lives, and about the dangers they face. How fishes get to look like fishes Fish become fishes either directly or indirectly. The less common direct route normally means giving live birth to the youngsters (when embryos in eggs are brooded internally in the reproductive tract of the female fish). Juvenile fishes then emerge at birth and tend to look like
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Above: The larval development of the white-margined sole (Dagetichthys marginatus). showing the yolk sac stage (A), preflexion stage (B), flexion stage in which the tail fin begins to develop (C), and the postflexion stage (D). Towards the end of the postflexion stage, the larva starts to transform into a juvenile and drastic changes occur. Larvae start acquiring scales, their guts change shape, and many physiological changes occur in the body to make it ready to move out of the plankton world into the juvenile habitat (such as estuary seagrass beds, rocky reefs, or sandy bottoms). In sole, one eye has to migrate to join the other on one side of the fish’s body, preparing the adult for life on the ocean floor. When all these changes are occurring, the larva is said to be ‘transforming’. BL refers to the body-length of the larva from the tip of the snout to the start of the tail fin, or the tip of the precursor to the spine (notochord) in younger larvae. Images: Ernst Thompson
the adults from the start. Freshwater guppies and mollies, for example, give birth to live young, as do all the large sharks. In some fish species, such as seahorses, the male carries the eggs in a pouch on his belly and he it is that broods and ‘gives birth’ to juvenile seahorses. Indirect development of fishes occurs when the fish embryo hatches from an egg into the stage called the ‘larva’. Most fish that people come across have developed in this way. They’re called oviparous (or, egglaying), with masses of eggs spawned and fertilized in the ocean’s waters outside the body of the female during spawning events, when adults congregate to reproduce. After the concentrations of adult fishes have spawned (deposited) their eggs and sperm, they swim away, leaving the rest to nature. The embryo develops in the egg, and the time that takes depends on many factors (such as the species, the age and health of the mother, and the water temperature). Many coastal fishes in South Africa (such as kob, spotted grunter, and pilchard) migrate to warmer waters to spawn. Tiny larvae as small as 0.5–5 mm emerge from the eggs and need a further few days, weeks, or months – again depending on the species and the ocean temperature – to develop into a fish that looks like the adult it came from.
Above: Cleared and stained specimens. Clearing and staining remove the flesh from the body and dye the bones and cartilage in red and blue, respectively, to allow for easy counting. The enzyme trypsin from pigs is used to eat away the flesh of the larvae. The clearing has to be monitored carefully to make sure that the larvae are not completely digested by the trypsin. Above right: Estuary mouth at Wavecrest.
What happens in the larval stage Outside the egg, after a larva has hatched, many organs and functions still have to develop. Larvae normally rely on a yolk-sac for nutrition until they have developed sufficiently to find food, pursue it, subdue it, devour it, and digest it. This is quite a feat for such a minute speck of life! Larvae are vulnerable, particularly during early development, and many die or are eaten in the dangerous, predator-filled world of plankton. Once they can feed well enough on their own and swim well enough to start making their way to a suitable nursery habitat, they just have to stay close to a food source and avoid being eaten themselves. Most fish larvae have tricks to help them succeed. For camouflage, they are mostly transparent, and many have sharp and/or serrated spines on their heads, making them hard for predators to swallow. Some even have extended rays off their developing fins that make them look like floating seaweed. These characteristics are lost when a larva becomes a juvenile fish.
bifasciatum, Belonoperca chabanaudi and Grammistes sexlineatus (Serranidae: Epinephalinae) with comparison of known larvae of other epinephelines”, Bulletin of Marine Science, vol. 48 (1991), pp.67–93.
The case of the dusky kob The dusky kob represents the dire predicament of many inshore fish species. A member of the family Sciaenidae, it is a favourite food-fish species, targeted by recreational and commercial anglers along South Africa’s entire coastline. Its population has been reduced to just 4% of the original pristine stock that existed before fishing pressure began about a century and a half ago. The dusky kob lives in shallow waters and relies on estuaries for its nurseries. Eggs are spawned in the marine environment. The tiny larvae that emerge move shorewards to estuarine nurseries by smelling them out, and then actively swimming into them in the early juvenile stage of development. They spend 5–6 years in their estuarine nursery until they reach sexual maturity and return to the ocean. Dusky kob adults come back into the estuaries to feed and build their energy reserves before their annual spawning migrations (mainly to the KwaZulu-Natal coast). Like many prized angling fishes, dusky kob grow slowly (to a maximum length of about 1 800 mm), mature late, and live to old age (the greatest known age is 42 years). The minimum length limit at which the fish can legally be removed by anglers remained at 400 mm for decades while stocks declined. The new linefish regulations in 2005 increased the minimum size to 600 mm, still way below the size at which the species is able to reproduce. When breeding fishes are taken out of a population, together with fishes that are not yet mature enough to breed, that population cannot survive. Legal destruction The dusky kob population is being legally decimated in the following ways: ■ large adults are being fished from estuaries by anglers before their annual breeding migrations ■ legal restrictions on fishing have not kept up with scientific knowledge. Emergency solutions To save the dusky kob – if it is not too late to do so – the following are needed: ■ regulations giving the fish two decades of ‘no-take’ status to allow the stock to rebuild (and anglers who, in the meantime, agree to take no dusky kob below 1 m in size) ■ once stocks return to health, a permanent closed season during spawning migrations and breeding periods (to protect spawning adults) ■ the inclusion in marine reserves of spawning areas, designated as protected no-take zones (to encourage breeding and maturation) ■ the creation of estuarine reserves that are closed to fishing (to prevent the fish from being caught during their most vulnerable phases and to allow them to grow to sexual maturity) ■ giving conservation priority status to estuaries, particularly those representing fish nursery hotspots (to protect these areas from the additional pressures of degradation caused by catchment and floodplain mismanagement, pollution and canalization, recreational damage from boating and bait-digging, and coastal building developments) ■ supporting the Southern African Sustainable Seafood Initiative (SASSI) – where consumers stop eating fishes whose populations are in crisis (www.wwf.org.za/sassi). Above: Dusky kob (Argyrosmus japonicus)
Illustration: Elaine Heemstra (in Coastal Fishes of Southern Africa)
Vicious cycle of decline Populations of sought-after angling and commercial food fishes are on the brink of collapse off South Africa’s coast. It’s estimated that the dusky kob population, for instance, is now only about 4% of what it was 150 years ago. This decline – particularly of large female fish – could end in extinction. Females grow older with age, and the bigger a female gets, the better she becomes at reproducing. A larger female produces more eggs. Her eggs are bigger, so they have more yolk, allowing the embryo to develop for longer in the egg before emerging as a larva. A larger, more developed larva has a better chance of survival, as it needs to spend less time in the dangerous plankton at sea, developing organs such as eyes, gut, fins, and muscles on its way to becoming a juvenile fish. Moreover, it becomes a juvenile fish more quickly, which allows it to find a suitable, safer habitat in which to settle – a reef or estuary, for instance. The impacts of fishing on the large breeding adults of a population (particularly females) have serious repercussions on larvae: ■ declining numbers of larger females mean fewer eggs
Above (left to right): Butterfly fish (Chaetodon unimaculatus) larva showing spines (6.6 mm) used for protection against being swallowed. Image courtesy of J.M. Leis and D.S. Rennis, in The Larvae of Indo-Pacific Coral Reef Fishes (University of Hawaii Press, Honolulu, 1983). Gurnard (Pterygotrigla sp.) larva (10.2 mm) showing head spines. Image courtesy of J.M. Leis and T. Trnski, in The Larvae of Indo-Pacific Shore Fishes (University of Hawaii Press, Honolulu, 1989). Soapfish larva (Diploprion bifasciatum) (16.2 mm) showing extended dorsal fin rays that trail around the larvae and make it look like seaweed. Credit: C.C. Baldwin, G.D. Johnson, and P.L. Colin, “Larvae of Diploprion
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South Africa’s Marine Protected Areas (MPAs) Vital to the management of protecting fishes across the world are marine protected areas (MPAs). Pressure from fishing in coastal waters over the last few decades in South Africa has caused marine linefish stocks to decline. The MPAs already in place are unable to give coastal fishes the protection they need. We now need more. What do our MPAs cover? Various levels of exploitation are allowed in the small and large MPAs and marine reserves along the South African coast, from ‘no take’ zones to angler limits within specified areas. About 17% of the coastline has some protection status, and the government aims to increase this to 20% by 2012. Why do they seem unable to counter the effects of fishing pressure? The number of MPAs is insufficient to cover the variety of habitats along our coast, and there are insufficient ‘no-take’ zones. Off-road vehicles on beaches for many decades allowed anglers access to even the most remote areas of our coast. The fact that commercial fishing in South Africa is worth over a billion rand and that the country’s recreational fishery is made up of more than 750 000 anglers means that there is massive pressure on our coastal fish stocks. What will new MPAs add that’s different and useful? New MPAs will protect new habitat types and new ecosystems, and also increase the number of areas protected. The proposed new Greater Addo National Park MPA in Algoa Bay, for example, will protect part of the bay ecosystem, and the large offshore component of the proposed Namaqua National Park will protect various offshore marine species traditionally targeted by commercial fishing trawlers.
Above (from top): Nadine Strydom driving a boat on an estuary. Boating skills are essential for larval fish research. Photograph: Ryan Wasserman Stereo microscope used for sorting and identifying fish larvae. Students pulling a larval fish seine net in a mangrove estuary. Right: This type of eyepiece micrometer is inserted into the eyepiece of a microscope to measure larvae smaller than 1 cm.
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■ the younger females that remain produce fewer and smaller larvae, as the size of hatched larvae is related to a female’s size and age ■ these smaller larvae have longer planktonic phases and are therefore more vulnerable to predators.
MPAs to the rescue The success of any fish population depends, first, on the successful survival of its larvae. Second, it depends on adequate conservation measures, and on appropriate management protocols and regulations being put in place to reduce fishing pressure, habitat loss, pollution, and the many dangers that human activities pose.
South African government agreements at the 2002 World Summit on Sustainable Development will increase the establishment of marine protected areas (MPAs), which, it is hoped, will help to improve the situation. To establish an MPA successfully, from a fish perspective, we need a sound knowledge of the fishes that need protection; their habitat, movements, and survival requirements; their larval and juvenile characteristics; and the patterns of current flow in the designated areas. Then scientists can assess and predict the ‘reseeding potential’ of the protected fishes on neighbouring unprotected areas. Can fishes in MPAs produce enough babies? How far can the young travel into neighbouring areas to replenish over-fished stocks there? These are among the questions that need answers. With new MPA expansion, information not previously thought important is now recognized as necessary in planning for efficient conservation. Larval fish scientists are studying the size at which the larvae of particular species become active swimmers, for instance, to make their predictions more accurate. New research findings, mainly from Australia, indicate that many reef-fish species, for example, return to natal reefs (in a process called ‘self-recruitment’) or remain close to where they were spawned. As this is where these particular larvae complete their pelagic2 stage in the plankton before moving to neighbouring reefs or estuaries, it would help the species if open-water areas next to a proposed reserve were to be protected too. As it is such a new discovery, selfrecruitment is poorly studied in South Africa and needs expert larval fish knowledge, time, and money (which are always in short supply). But if the behaviour of larvae of temperate species reflects that of adults and larvae of tropical reef species, then South Africa also needs such knowledge for its marine reserve planning. In a nutshell, the work of marine reserves is much improved by research into the early life of 2. Pelagic organisms are those that swim or drift in a sea or a lake, as distinct from those that live on the bottom. They are classified as plankton (which drift) and nekton (which actively swim through the water, such as fish, jellyfish, turtles, and whales).
Above: The proposed Addo Elephant National Park Marine Protected Area.
the fish species being protected – by knowledge, for instance, of what habitats they prefer and how the ocean influences the dispersal and settlement of their larvae out of the plankton into safer territory. MPA protection aimed at managing and conserving breeding adults, as well as fish larvae and juveniles, can have far-reaching benefits for the work of saving and protecting our fish populations.
University. This family includes some of the most important – and heavily exploited – linefish species in the country, such as blacktail, strepie, stumpnose, and white steenbras. Further trials are planned on the family Sciaenidae (which includes the dusky kob and geelbek). Overfishing has reduced the populations of many sparids (such as red roman and white steenbras) and sciaenids (such as dusky kob)
Staying in sync with science Our current larval fish research focuses on a region in the eastern half of Algoa Bay, where the new Greater Addo National Park MPA is about to be established. Master’s student Paula Pattrick and I are trying to ascertain what fishes are breeding there and what larvae use the area as a nursery. Once the reserve is proclaimed and fishing there is reduced or curbed, this information will help us to monitor the recovery of fish stocks in this location, on the basis of larval fish densities and the occurrence of species over time. We’re also measuring the speed and direction of currents in the area with Marine and Coastal Management (of the Department of Environmental Affairs and Tourism), also involved in the project. So far we have discovered that the currents are driven by local winds and that they change according to the season. This information will allow us to predict current movement in the future and therefore where the larvae will be concentrated. In addition, we’re testing – for the first time in South Africa – the swimming abilities of fish larvae. Our trials on larvae of the family Sparidae (breams) are being conducted in a specially designed swimming chamber at Rhodes
Image: Anè Oosthuizen (SANParks)
Top: A swimming chamber in the Department of Ichthyology and Fisheries Science at Rhodes University (Port Alfred Research Station) for testing the endurance and swimming abilities of larval fish. The morphology (body shape) of larvae within each family is very similar, so the results from a single species apply to others in the family as well. The overall body shape of a larva determines how good a swimmer it is. Photograph: Nomtha Myoli (SAIAB) Above: Raceway used for swimming trials on larval fish.
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– they are very popular with anglers – and because they grow slowly, removing large fish out of the ocean has massive implications for the population size. In 1985, for example, scientists discovered that dusky kob become sexually mature and able to reproduce when they reach the size of 1 m – that is, when they are about 5–6 years old. Yet, for the past 20 years (1985–2005), the minimum size limit allowed to anglers remained well below this size – at just 40 cm. It was increased to 60 cm as of 2005, when new regulations came into effect, but this is still too small – these fish populations are in crisis. In such cases, the law lags so far behind scientific knowledge that fishing practice is
Above (clockwise from left): Blackmusselcracker (Cymatoceps nasutus); Red stumpnose (Chrysoblephus gibbiceps); Yellowbelly rockcod (Epinephelus marginatus); Red steenbras (Petrus rupestris). Right: White steenbras (Lithognathus lithognathus) Illustrations: Elaine Heemstra (in Coastal Fishes of Southern Africa)
Size and age information for some common angling fishes Scientific name
Minimum size Age at Length at sexual maturity limit (mm TL*) minimum size (mm TL*) limit (years)
Age at sexual maturity (years)
Poenskop, black musselcracker
Both sexes: 530
Both sexes: 10
Females: 1 070 Males: 920
Females: 6 Males: 5
Bronze bream, bluefish 300
Diplodus cervinus hottentotus
Bronze whaler shark
Usually < 1
Females: 1 900 Males: 1 750
Females: 26 Males: 20
White steenbras, pignose grunter
Females: 625 Sex change: 870
Females: 6.6 Sex change: 17
Females = 5 Males = 6
Females: 340 Males: 310
Females: 6 Males: 6
Females: 180 Sex change: 300
Females: 2.5 Sex change: 6–14
Spotted grunter, tiger
Females: 390 Males: 330
Females: 3 Males: 2.5
Females: 850 Males: 750
* Total length **These minimum size limits were those raised in the new regulations of 2005. For the other species listed here, the minimum size limits remained as before. Note: In some cases, lengths for fishes growing in different climatic regions have been averaged.
Stocks of species shown in bold typeface are severely depleted off the South African coast. In all these cases (and others as well), the minimum size limit that anglers are allowed to catch have for decades been set lower than the size at which the species achieves sexual maturity (that is, the ability to reproduce). This means that the species have been fished out at higher rates than their capacity to breed, with serious consequences for their populations, now and in the future. New size-limit regulations (from the end of 2005) will need time to take effect, as the fish grow slowly. The regulations now in force still, however, allow species in crisis to be caught legally below their breeding size.
34 Quest 3(2) 2007
New facts about larvae
like the legal killing of children who’ve never had a chance to grow to adulthood or to have children of their own. Many other fish species share this predicament. Sharks, for example, are often considered to be pests, but they are in fact top predators needed to keep the ecosystem in check. Some sharks take as long as 25 years to reach sexual maturity, but no size limits are set to protect them and people are allowed to kill however many they may find. Determining the larval swimming abilities of sparids, sciaenids, and others, will help us to predict how far their larvae are carried by currents before these tiny fishes can outswim them, and redirect themselves to safer places of their choosing. Such knowledge helps to determine how many MPAs we need along our coast. The exact placement of MPAs as well as what happens within them – where in the MPA people should be allowed to continue fishing and where the environmentally sensitive areas are – also need to take into account the needs of other marine faunal and floral groups requiring protection. People who fish are often ignorant of such facts and implications, and government regulations have not always kept up with the latest scientific information. Most anglers believe, for instance, that it is not possible for them to fish the fishes out of an area if all they use are hooks and line. Many still think that the ocean can generate never-ending supplies of seafood. All over the world, the data suggest otherwise. Checks and balances need to be imposed; people need to understand how much impact they have on the environment; fisheries and human developments need to be based on scienctific evidence and guidance. Otherwise overfishing and environmental degradation will rob our children and grandchildren of sharing our enjoyment of fishes in the wild. ■
Q Fact file
Until about a decade ago, scientists thought that larval fishes couldn’t swim properly at all, but moved by drifting passively in ocean currents. Research conducted since the late 1990s shows larval fishes to be highly capable swimmers, in fact, able to detect and select suitable habitats and currents. According to Australian researchers, larvae of coral reef fishes can swim at average speeds of 15–20 cm per second and orientate their swimming towards pre-recorded reef sounds played to them in tanks. They can also swim for days without food or stops. Larvae on the Great Barrier Reef can cover the equivalent of 50 km in as little as three days. They orientate towards the sun, magnetic fields, and the hydrostatic pressure changes associated with tides. South African research on larval fishes is still in its infancy. But we have started to research larval fish requirements and their sensory abilities, and we’ve already discovered some useful facts. Nadine Strydom’s research on larvae in surf zones has shown that some species, such as Cape stumpnose (Rhabdosargus holubi) and freshwater mullet (Myxus capensis), select deeper areas in the surf zone where current flow is slower. These larvae need to seek out estuaries, either for use as sheltered nursery areas or, in the case of the mullet, as a passage to the river where the catadromous adult fishes live (that is, fishes that live in freshwater but breed out at sea). Further investigations show South Africa’s surf zones to be popular among the larvae of particular species using estuaries along our coast as nurseries – such as stumpnose, mullet, and mooney. Larvae seem to use their keen sense of smell to find nursery areas, as we have discovered from field observations based on cueing in plumes of water flowing out of estuaries. Evidence is mounting that they lie in wait for specific cues that enable them to make their way to the right areas. South Africa’s estuaries play an important nursery role, as our coast does not have many sheltered bays and coves in which larvae can shelter while they feed and grow. This is how the process works. Rainfall that brings freshwater to our estuaries flows out to sea and is transported by currents along the coast. This water takes with it smells (that is, chemical signals) from the nursery areas, making it possible for larvae of coastal fishes, such as kob and spotted grunter, to seek them out. Once these larvae get a whiff of a nursery, they seem to be able to follow a gradient of smell (from weakest to strongest) to the estuary. There they spend a few years growing up, and enjoying shelter and abundant prey. Most important, they are less likely to be eaten in these locations, as few marine predators of fish larvae can tolerate the low salt content of estuarine water. When the larvae reach sexual maturity, they leave the estuary for adulthood in the ocean. Right: Upper reaches of estuaries are good nursery areas for marine fish larvae. Very few predators can follow them into water with the low salt levels (salinity) found there. Below: The mouth of the Heuningnes Estuary – a typical nursery area for fish larvae.
Dr Nadine Strydom is a marine biologist at the South African Institute for Aquatic Biodiversity (SAIAB). Her research field is larval fishes, in particular their habitat and movement and the ways in which they relate to the ocean world around them. She is at present the only scientist in South Africa working on the ecology of fish larvae. For reports on recent research on larvae, read M.J. Leis et al., “Sensory environments, larval abilities and local self-recruitment”, in the Bulletin of Marine Science, vol. 70 (2002), pp.309–340; N.A. Strydom, “Occurrence of larval and early juvenile fishes in the surf zone adjacent to two intermittently open estuaries, South Africa”, in Environmental Biology of Fishes, vol. 66 (2003), pp.349–359; and N.A. Strydom and B.D. d’Hotman (2005), “Estuary-dependence of larval fishes in a non-estuary associated South African surf zone: evidence for continuity of surf assemblages”, in Estuarine, Coastal and Shelf Science, vol. 63 (2005), pp.101–108. There are also J.M. Leis and B.M. Carson-Ewart, The Larvae of Indo-Pacific Coastal Fishes (Brill: Leiden, 2000); popular articles in The Fishing Journal and The Fishing and Hunting Journal; and the indispensable handbook, Phil and Elaine Heemstra, Coastal Fishes of Southern Africa (SAIAB and NISC, Grahamstown, 2004). The South African government’s regulations for catching linefish are in the Recreational Fishing Information Brochure (Department of Environmental Affairs and Tourism, 2005) at www.deat.gov.za.
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Looking after wasps & bees Farmers need the help of wasps and bees as pollinators and predators, and the insects need farmers to take care of them properly. Sarah Gess explains how people can help their insects to live and be well.
asps and bees help ecosystems to function properly. As predators and pollinators, they’re needed food production – for crop and stock farming – and game and flower reserves can’t survive long without them. Their loss has a cascade effect, so maintaining their essential populations is crucial. For that to succeed, we have to know about the lifestyles of these insects and what they need. Any sizeable area in the semi-arid lands of southern Africa would normally have several hundred species of bees and aculeate wasps (that is, wasps with stings). With increasing aridity, the numbers of species decrease. Most are ‘solitary’ species, with each female nesting independently of other females. All visit flowers to obtain nectar for nourishing adults, and those whose size and behaviour fit the flowers they visit are potential pollinators. Bees and pollen-wasps provision their nests with pollen and nectar to feed their larvae, so they make many more flower visits than most aculeate wasps do. In consequence, bees and pollen-wasps are generally likely to be more efficient pollinators than predatory wasps, which provision their nests with live insects or spiders paralyzed
with venom from the sting. The important role of predatory wasps – like all predators – is to help to maintain balanced population sizes of their prey. Nests and food People who develop arid and semi-arid areas can often do great damage without realizing it. So the more that’s known about the life of bees and wasps, the more careful it’s possible to be. Maintaining viable populations of aculeate wasps and bees means meeting their nesting requirements. The largest number of species nest in the ground in friable (that is, crumbly) or non-friable soil. Others nest in or on vertical banks, in or on plants, or on stones. Some ground-nesters need friable soil and others prefer hard clayey soil in which to excavate their nests. In all cases, they need ground that’s not heavily trampled by stock or disturbed by regular cultivation or any other destructive activity. If the soil they choose is clayey, then they also need water. In clayey soil, nests are usually surmounted by characteristic, delicate nest-entrance turrets constructed from mud pellets extracted from the shaft. For nest-building, the insects imbibe water from a water source and regurgitate it at the nest site to soften the ground so that a shaft
Photographs and drawings: Sarah K. Gess unless otherwise indicated
Above: Sarah Gess on a collecting trip to the Sperrgebiet, southern Namib, Namibia. Photograph: Fred Gess Above left: Pollen-wasps (Quartinia propinqua) visiting flowers of Berkheya schinzii (Asteraceae). Left: Logo for the Hymenoptera collection, a pollen-wasp, Ceramius lichtensteinii.
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PLANTS VERTICAL BANKS
sand, ‘sandstone’ & shale
Left (from top down): A pollen-wasp (Ceramius clypeatus) visiting a flower of Aspalathus spinescens (Fabaceae: Papilionoideae). A nyssonine wasp (Bembix bubalis) transporting its syrphid fly prey in flight. Photograph: Harold Gess
and cells can be excavated. The water must be clean, not polluted. Many species stand at the water’s edge whilst imbibing water, and others stand on the water surface. The source of water, therefore, must have a shallow shore at some point, and the water must not be fast moving. Vertical banks of soil or rock are home to a diverse array of nest excavators and users of pre-existing cavities. For this reason, cutting back an established bank may be disastrous for a wide range of insect species. Some species use green plant-stems for nesting, but most species that excavate nests or use preexisting borings in plant-stems choose dry stems. These – depending on the species – may be large branches of trees, twigs of various diameters, pithy stems (such as aloe inflorescences), or hollow stems such as those of reeds. Bush clearing, the removal of trees, shrubs, and reeds associated with watercourses, and heavy collection of firewood can have grave consequences. Species that use pre-existing cavities, as well as constructors of aerial nests (that is, nests on a support, be it a bank, rock, stone, or plant), require building materials. These, according to
A reed cut longitudinally to expose the nest of a carpenter bee (Xylocopa scioensis), which cuts an entrance hole into the hollow stem, a ready-made burrow. Above: Pie diagram showing proportional use by aculeate wasps and bees of different nesting situations in a community of 300 species on the farm Hilton, near Grahamstown (studied by Fred and Sarah Gess in the 1970s). Further research has shown that these proportions of species nesting in friable soil, non-friable soil, in or on vertical banks, in or on plants, and on stones are typical for the semi-arid areas of southern Africa. Above right: Drawing of a burrow of a carpenter bee (Xylocopa sicheli), showing the provision of loaves of pollen and nectar paste, as well as eggs and larvae (one per cell). Right (from top down): Within a trap nest: a nest-cell of a sphecid (Isodontia pelopoeiformis), showing long-horned grasshopper prey and an egg. Photograph: Fred Gess A sphecid wasp (Sphex decipiens) transporting its long-horned grasshopper prey. Photograph: Harold Gess The pebble and resin cells of an osmiine bee (Othinosmia jansei), constructed on a stone with the lower half buried in the ground. Photograph: Fred Gess A mud-pot nest of a potter-wasp constructed on a plant- stem. Photograph: Fred Gess A nest of a pollen-wasp (Priscomasaris namibiensis), with soil removed from one side to show the structure of the subterranean burrow.
Quest 3(2) 2007 37
Top left: A pollen-wasp (Jugurtia codoni) collecting pollen from Codon royenii (Boraginaceae), from which it collects nectar but of which it is not a pollinator. Photograph: Robert Gess Top right: A nester that uses water to excavate and construct a nest in non-friable, clayey soil. This pollen-wasp, Priscomasaris namibiensis, is standing on its nest entrance turret, holding a mud-pellet extracted from the burrow. Left: A pollen-wasp (Ceramius braunsi) visiting flowers of Arctotis laevis (Asteraceae). Photograph: David Gess Left middle: Student Mxolisi Stemele inspecting trap-nests set out to attract cavity-nesting wasps and bees. Left below: A pollen-wasp visiting a flower of Peliostomum (Scrophulariaceae). Photograph: Robert Gess ▲
species, may include mud, resin, plant fibres, loose soil, small pebbles, and discs cut from leaves or petals. If the right materials are not available, nesting can’t succeed. In almost all cases, a single larva is reared in each nest cell. All bees provision a cell before they lay an egg into it and seal it. Some wasps (such as pollen-wasps and potter-wasps) lay an egg first and then provision the cell, but others lay the egg onto the prey, when a single large prey is provided, or onto one of the prey, when several are used. The cell may then be sealed, or prey may be added during the development of the larva. Bees and pollen-wasps differ a great deal in their choice of nectar and pollen for food – some species are highly specialized with few kinds to choose from, others have far wider options. Most wasps – those that feed their larvae on insects or spiders – range from species-specific to groupspecific choice of prey. Their environment has to meet the requirements of their prey organisms. Therefore what appear superficially to be small changes in an ecological system can have a significant cascade effect. Agricultural dont’s and do’s The right kind of landuse makes a huge difference to the diversity and survival of pollinating and predatory insects that, in their turn, help crop- and stock-farming to succeed. The greatest dangers – particularly to solitary bees and aculeate wasps – come from ■ high livestock densities ■ heavy selective grazing and browsing ■ excessive trampling ■ water pollution by animals ■ large-scale impoundment of water ■ canalizing of water ■ extensive replacement of natural vegetation by cultivated pastures or crops ■ use of insecticides for protecting crops and grazing ■ the spread of invasive exotic plant species ■ cutting down bush
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■ intensive removal of dry wood. The best ways to look after aculeate wasp and bee populations on land used for agriculture or game are ■ take care not to overstock, in this way reducing the danger of excessive trampling and excessive selective grazing and browsing ■ reduce the effects of seasonal selective grazing and browsing by moving herds at frequent intervals ■ protect the nesting areas of ground-nesting bees and wasps from trampling ■ cater for the needs of bees and wasps when designing irrigation systems or stock-watering points ■ leave strips of natural vegetation untouched when creating cultivated pastures or planting crops ■ consider the effects of insecticides (if they have to be used) on organisms in areas other than those targeted, and to take precautions to prevent contaminating surrounding areas and water sources ■ control invasion by exotic plant species ■ cut down bush in such a way as to retain areas or strips of bush-covered land ■ restrict the removal of dry wood ■ help populations of cavity-users by providing blocks of wood drilled with suitable holes (this is an effective way to look after populations of megachilid bees for pollinating lucerne, for instance). When planning flower reserves or general nature reserves, it should be remembered that most flowering plants (even those that can self-pollinate in the absence of pollinators) require crosspollination to prevent them from degenerating over time. Before delimiting the reserves, it’s worth studying the area in advance, to establish what insects are associated with what plants and what those insects’ requirements are. Then it should be possible – at least in the case of bees and wasps – to ensure that their nesting sites are included in
Why we need collections Southern African aculeate wasps and bees Very few wasps and bees – indeed very few insects – can be identified in the field by sight. As a general rule, identification requires collecting specimens, examining them under magnification, using identification keys, and comparing them with authoritatively identified specimens. So, to understand what is happening in real life, it’s crucial to have access when necessary to specimens lodged in reference collections. For anyone to be able to discuss and understand them, insects must be named and described. The specimens used as a basis for scientific descriptions are called type specimens. All type specimens should be clearly labelled as such and housed in a recognized collection facility. Type specimens are required for comparison with specimens that come close to a species description but cannot be attributed to that species with certainty. Many species of wasps and bees – and insects in general – have not yet been discovered or scientifically described. When any study is conducted, representative specimens should be preserved, fully labelled, and deposited in a recognized collection facility. These specimens are termed voucher specimens. When a researcher conducting a field study collects specimens, he or she should take the opportunity to collect as much information associated with the specimen as possible – in addition to the minimum of locality, date, and collector. Code numbers should be used to link the primary specimen with associated field-notes and associated specimens such as nests, forage plant samples (which should be preserved as herbarium specimens), prey, or parasites. Grahamstown’s Albany Museum, within the terrestrial insect collection, houses what is probably the world’s largest collection (some 175 000 specimens) of solitary aculeate wasps and bees of southern Africa. The collection is unique for the high percentage of specimens linked to biological data (especially relating to nesting and flower visiting) and specimens of nests, prey, parasites, and forage plants. It contains the voucher material for most of the ethological studies (behavioural studies in the natural environment) of southern African solitary aculeate wasps. In addition to specimens of aculeate wasps and bees individually collected with a handnet, the collection contains large numbers
of specimens, derived from diversity and flight-period studies at specific sites, collected using Malaise traps and bearing an extra label indicating the method of collection. While Fred and Sarah Gess were servicing Malaise traps on a farm near Grahamstown 35 years ago, Fred pointed out a remarkably fine retort-shaped mud turret. Sarah’s curiosity was aroused and the investigation of this nest led to the expansion of the Gesses’ endeavours from pure taxonomy and distributions of aculeate wasps and bees to the behaviour of these insects, and to a long-term, ongoing project on the species representation, distributions, and role of aculeate wasps and bees in semi-arid to arid areas in South Africa and Namibia north to the Kunene, with comparative studies in Arizona and Australia. Alan Weaving, formerly an economic entomologist, joined the Gesses from 1981 to 1996 and, after valuable initial studies in the Eastern Cape, chose coastal KwaZuluNatal as his study area. A start has been made on inputting the label data of the terrestrial insect collection into a relational database (that is, a database composed of several forms capturing various categories of data, linked in such a way that it can be searched across categories)*. The first collection selected for entering into a database was the bee collection, which, having a high number of flower-visiting
Top: Malaise trap on Hilton Farm, northwest of Grahamstown. Fred Gess with Fort Hare students. Above: Insect cabinets, some teaching cases, and Fred Gess, Department of Entomology and Arachnology, Albany Museum. records, is important not only for people interested in bee distributions but also for those concerned with bee/flower interactions. For example, it is currently being used by the African Pollinator Initiative (as represented by Connal Eardley of the Plant Protection Research Institute, Pretoria). Further progress with the database requires additional funding and manpower.
Above: Diagram of Codon royenii (Boraginaceae) with silhouettes of Xylocopa lugubris and Jugurtia codoni.
the reserve and that they have access to suitable water sources. Knowing our wasps and bees and looking after their needs has many benefits – including ways to thank them for their services, so important to our agriculture and food production. ■ Since 1972, Dr Sarah Gess has worked at the Albany Museum in Grahamstown with her husband, Dr Fred Gess, on the taxonomic representation and roles of aculeate wasps and bees in southern Africa, particularly in the semi-arid to arid areas. Her special interests have been nesting and flower associations. Other family members have joined in with photographs to accompany this article.
* The database can be accessed on the South African Biodiversity Information Facility (SABIF) or by applying direct to Fred and Sarah Gess at the Albany Museum. Specialists worldwide undertaking generic revisions have borrowed and continue to borrow specimens relevant to their studies. The collections are also used for teaching at all educational levels from pre-primary to tertiary, and for workshops and talks for the SciFest and interested members of the public.
For more information consult: F.W. and S.K. Gess, “Effects of increasing land utilization on species representation and diversity of aculeate wasps and bees in the semi-arid areas of southern Africa” in J. LaSalle and I. D. Gauld (eds.), Hymenoptera and Biodiversity (CAB International, Wallingford, 1993, pp.83–113); S.K. Gess, The Pollen Wasps: Ecology and natural history of the Masarina (Harvard University Press, Cambridge Ma, 1996); and S.K. Gess, “The Karoo, its insect pollinators and the perils which they face”, International Pollinator Initiative Case Study 35 (2001) at www.ecoport.org. A list of publications by the Gesses and Allan Weaving on the nesting and flower associations of wasps and bees can be found at: www.ru.ac.za/affiliates/am/ento.html. For updates, e-mail F.Gess@ru.ac.za or S.Gess@ru.ac.za, or write to Dr S.K. Gess, Department of Entomology and Arachnology, Albany Museum, Grahamstown, 6139.
Quest 3(2) 2007 39
Africa’s natural history collections – Paul Skelton argues for investment in African natural history collections for Africa.
provided much of the world’s knowledge of Academy of Sciences in San Francisco – the rom the point of view of a natural global biodiversity. list goes on. systematist, Africa’s biodiversity is Most governments of advanced and rich By contrast, I’m aware of few natural a paradox: extraordinarily rich – in nations seem prepared to invest reasonably history museums in Africa that have many ways unparalleled – in biodiversity, well in these resources. For example, the had major re-investment in recent times. yet the continent is embarrassingly Smithsonian Institution budget request to the In Kenya, with its spectacular national impoverished in terms of indigenous US Congress for 2008 is $678.4 million, which biodiversity constantly exposed in the scientists and its own natural history includes $10 million for alterations to the international media, there is a good collections. It’s as if this incredible wealth of off-site Museum Support Centre in Suidland, national history museum in Nairobi, natural living resources has little or no value Maryland, and $22.5 million to revitalize the currently undertaking a rebuilding or meaning to Africa itself. If so, why should National Museum of Natural History. The programme (“Museum in Change”) funded this be? Is this one of the unfortunate UK government grant to London’s Natural largely by the European Union, which has legacies of colonialism? Whatever the History Museum in 2006 was £41 470 million. contributed KSh760 million. reason, we need to ask “What should and In 2006 the Royal Ontario Museum in Canada Other natural history museums exist can be done about it now?” raised $201 million, including $42 million in Africa, but many if not most, in my To understand what seems to be underfrom government and $72 million from the experience, are either run-down or investment in natural history collections public sector, through their Renaissance marking time, their collections in disarray in Africa, consider those in the developed Campaign for construction projects. or slowly deteriorating. world. There, national and large regional Even in South Africa, somewhat out of step natural history museums, public or private, with the rest of Africa in having several large are housed in grand buildings in the natural history museums and collections, heart of capital or major cities. Their the overall recent record is that such international stature is a source of It is time for African institutions are struggling to maintain pride and prestige for their nations. themselves. Does Africa need such treasure? nations to expand their own In 2005, the Durban Natural Or is it surplus to scientific expertise and traditions in natural Science Museum completed a new requirements and mere fool’s gold history and natural history centre for its collections, so perhaps in a continent where poverty and collections. South Africa is now showing signs of social deprivation at the most basic renewal and interest, especially after the level are the order of the day? promulgation of the National Environmental Great collections Management: Biodiversity Act (No. 10 of Investing in biodiversity Many of the great museums have existed 2004) (NEMBA) and the establishment of the At this time of global crisis in biodiversity, for several centuries, signalling enduring South African National Biodiversity Institute the need for nations to invest in the national commitment – among the oldest as the agency responsible for taxonomy and resources that enable science to assess the are, for example, the National Museum of natural history collections. state of nature, should be unquestioned. Natural History in Paris, France, founded The investment by the National Research The global record of re-investment in in 1793 but dating back even further to the Foundation in a new building to house the natural history museums in recent years is establishment of a royal garden in 1635. wet collection of SAIAB for the National Fish impressive. Some institutions have provided The British Museum officially began with an Collection may also signal national awareness major upgrades for their collections, Act of Parliament in 1753, and the Natural of, and preparedness to assume, South such as the American Museum of Natural History Museum, as it is now known, has Africa’s responsibilities to develop and care History in New York City, the National been at its present site in South Kensington, for its scientific biodiversity resources. Museum of Natural History, Smithsonian London, since 1880. The Swedish Museum of Natural History in Stockholm dates from 1739. Such museums and their collections are considered valued treasures of the state. The science they perform and the wealth of the natural history collections they nurture have
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Institution in Washington D.C., the Royal Museum for Central Africa in Tervuren, the Naturalis in Leiden, the Swedish Museum of Natural History in Stockholm, the Royal Ontario Museum in Toronto, the California
The delegation option Should African nations in fact develop and foster their own collections of natural history, though? Can they commit themselves to carry the substantial costs of providing suitable
riches or fool’s gold? infrastructure, and of collecting, caring for, and managing such collections? Or should they rather delegate to nations that can afford it? It’s a complicated issue. Running successful collections means having trained, skilled staff, familiar with the business of international systematics science. At present, few skilled African scientists or curators are available. The training in curation offered by some museums in Europe or North America is expensive – apart from the question as to whether training outside Africa is appropriate for conditions in Africa that are very different from those in rich countries. The supplies of services and materials for the care of collections are not equivalent, for instance. In addition, with technology driving rapid change in taxonomic and systematics research, the very nature of collections is changing equally rapidly. There’s an increasing need to preserve not only whole organisms for study but also tissues suitable for biochemical (especially DNA) analysis. Equipment for technologically driven studies requires specialized laboratories, expertise, and equipment. Such changes present new challenges for institutions and curators. Colleagues in the developed world (with its superior resources) have pointed out to me that existing collections in Europe, North America, and elsewhere include the type specimens of most described African animal and plant species. Establishing our own collections in Africa will not replace these types. Scientists, wherever they are, refer to the types as well as to the historical collections lodged internationally. Even when new collections include previously undescribed species, African researchers will still need to refer to the established foreign ‘out of Africa’ collections, either via electronic databases or through visits abroad made at great cost in time, money, and effort. Repatriation of material to African collections is unlikely and is not the answer, although digital images and data of type specimens will increasingly assist studies in future.
In such a globalized world, is it worthwhile, therefore, or even feasible for African nations to develop their own natural history collections? Is it not better to foster close relationships with established institutions in developed countries and embark on collaborations and partnerships that train local scientists, enable visits to collections, undertake joint expeditions, and facilitate collecting and export permits? African collections for Africa Research collaborations are clearly in everyone’s best interest. But delegating African collections to developed countries seems simply to favour the status quo and denies African scientists and nations the opportunity even to begin to stand on their own feet. Without collections in Africa, the continent’s scientists and research structures will remain impoverished in terms of resources and unable to provide their own people with crucial, local knowledge. They will forever remain at the benevolent mercy of foreign nations, required to do no more than to explore, study, and reveal to the world the richness of Africa’s biodiversity. Such dependency would inevitably mean that valued traditions will never be established; that the cost of conducting systematic research will never be challenged but remain prohibitive for most African scientists; and Africans will never be in a position to set their own agendas or priorities. For science at large, African biodiversity would remain a global feast at which African scientists will be uninvited bystanders, without the facilities to earn the respect or recognition that is their due. For this reason, I believe it is time for African nations to expand their own expertise and traditions in natural history and natural history collections. There’s much to be done, but the future holds unlimited scope. What’s to be done? Given the views from the developed world voiced above, what has to be done to achieve the paradigm change needed
for us to engage at the highest level with Africa’s biodiversity? ■ We need to develop self-belief and determination, and to have confidence in Africa’s ability and means to generate its own local systematics experts and custodians of natural history. ■ The few science leaders in Africa need to start the process of convincing the international community that this is the right path for Africa, and that scientists everywhere should support and invest in African initiatives, for their own and Africa’s benefit. ■ We have to develop partnerships and genuine collaborations. ■ Politicians and other decision-makers must be brought on board, to support the development of systematics knowledge, expertise, and resources for Africa. ■ Institutional leaders and governing boards must inform and educate politicians and bureaucrats how museum collections can serve national needs and interests, and what support these institutions require to do a good job. ■ Educators must bring systematics into African curricula and generate the thirst and passion for biodiversity that is at the heart of any healthy scientific tradition. In time, and with the right support, will come the pride and power of success. Then Africa will better serve its own interests in terms of understanding and conserving its wealth of biodiversity. ■ Professor Paul H. Skelton is the Director of the South African Institute for Aquatic Biodiversity and a key figure in the planning and construction of the Institute’s new wet collection facility. Opposite page (from the left): SAIAB building, Grahamstown. Photograph: Nomtha Myoli Swedish Museum of Natural History, Stockholm. Natural History Museum, London. Above (from the left): Royal Museum for Central Africa, Tervuren. Zoology Gallery, National Museum of Natural History, Paris. Darwin Centre, Natural History Museum, London. Images: Paul Skelton unless otherwise indicated.
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The S&T Tourist Q
Learn green living in Joubert Park Michelle Nel describes the GreenHouse Project, a model for sustainable building and living, in the inner city in Johannesburg’s Joubert Park.
axis hoot, hawkers rule the pavements, 20 000 people walk through Joubert Park each day, while a green oasis tucked away in the north-west corner opens its doors to anyone wanting to learn about sustainability. The GreenHouse Project (begun in 1993) demonstrates green1 alternatives with working examples of ways to organize, plan, build, landscape, grow food, and save money, materials, energy, and water. To encourage people to become more environmentally conscious, it suggests installing greywater systems to recycle water, for instance, and using environmentally friendly paint for walls. This is the only African environmental demonstration centre in a dense inner-city environment. It practises what it preaches, creating a practical knowledge base for ‘greening’ greater Johannesburg. The project’s first ‘green’ building (an office and resource centre) was constructed on the site in 2002. A recycling area gives impetus
to the goal of ‘zero waste’, with its focus on sorting paper, bottles, plastic, tin and glass, generating jobs for inner-city residents. It has natural lighting, a roof garden, and space to sort and store recyclables. The Victorian conservatory (a listed heritage building) is being renovated. A straw-bale, timber, and brick double-storey structure is under construction, showcasing various ‘green’ building technologies (for instance, hydraform bricks, consisting of 5% cement and 95% compressed clay and sand). These projects provide experiential learning in green building through ‘learn & build’ courses. Examples of products demonstrated at the centre include solar water heaters; energy-efficient and non-polluting cooking devices such as solar cookers, gel fuels and stoves, fuel conserving stoves, and hotboxes; greywater recycling systems; and useful household items made or reclaimed from waste. The project is also testing traditional and
Left (from top): A youth workshop taking place in the partly renovated conservatory. • The sun provides the heat for this shiny solar parabolic cooker. • Permaculture garden volunteer shows off some seedlings. • Women sorting recyclables at the GreenHouse Project recycling centre. Below: The double-storey ‘earth’ building takes shape. Right: Outreach officer France Maleme in the herb garden next to the water tank. Photographs: Michelle Nel
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1. ‘Green’ describes a holistic approach to the environment, which places ecological sustainability within the framework of social justice, an equitable share of resources, and better quality of life for all.
Q Books Free tours of the GreenHouse Centre are available every third Saturday of the month 10:00–16:00. Open days coincide with workshops on topics such as permaculture gardening. Call to find out what’s on. The resource centre has a free reference library, open Monday to Friday, 10:00–16:00.
Can you help? Call the GreenHouse Project if you have building materials, vegetable seeds, gardening or building tools, stationery, furniture, or other useful items to give away, or if you wish to make a direct donation2.
new alternatives to conventional construction, such as the straw-bale wall that has been used to close off the boardroom. Principles of ‘green’ energy include natural lighting in the building and large north-facing windows and insulation to improve temperature control. Cellulose installation in the ceiling and reflective glass reduce energy use. Small companies and local artists were contracted to help with the building, thereby boosting local economies. The gardens on the site are used for training in permaculture principles for the extensive flatland community around Joubert Park. For example, pre-school children in Hillbrow have now begun planting vegetables under a plastic bottle cut in half, a method that conserves water and increases seedling survival rates. “We envisage a broad spectrum of visitors, including building professionals, academics, school groups, local and international tourists, and people interested in sustainable development and healthy living,” says executive director, Dorah Lebelo. ■ For more information, contact Dorah Lebelo on (011) 720 3773 or e-mail firstname.lastname@example.org. Visit www.greenhouse.org.za.
Where are we heading? The Meaning of the 21st Century: A Vital Blueprint for Ensuring our Future. By James Martin (Random House: Eden Project Books, 2006). ISBN 9 781 90391 985 9. Software specialist and former rocket scientist James Martin founded the James Martin 21stCentury School at Oxford University in 2005 to identify solutions for the biggest challenges currently facing humanity. His book outlines problems such as the widening gap between rich and poor, the devastating loss of biodiversity worldwide, overpopulation, and climate change. But from beginning to end it also creates visions of a better world, with suggestions on “how to get there from here”. He argues both sides of controversial cases persuasively. On the subject of GM farming, for instance, he presents “vitally important reasons for caution” (such as the risk that pollen could spread in the wind and fertilize non-GM plants, including wild ones, or create new herbicideresistant weeds). Nevertheless, he supports genetic improvements as important “weapons in the war against starvation and malnutrition.” Written for the interested lay reader, in language that reaches everyone of any age who wants to grasp where we’re heading, Martin’s book ranges across the sciences, philosophy, sociology, economics, to explore the human situation as it really is, and to design solutions. He faces head on the need for moral change in a world where the poorest countries suffer extreme poverty, disease, and food insecurity, for example. But each argument convinces you that things can be made better. Although the gross inequalities that accompany globalization are
among the most difficult challenges of our time, “the abolition of extreme poverty is achievable”, he asserts. This book rings true because it presents each case so clearly and logically, avoids vague abstractions, and always illustrates with specifics. Explaining the need for any future civilization to be “sustainable”, he adds: “It must not take more from nature than nature can replenish; we must not meet our needs by stealing from future generations…. Environmentalism is not about tree-hugging; it’s about cancer, lung disease, birth defects, deaths from bad sanitation, food security, violent weather and quality of life.” This book is so readable – and so important – that it should be discussed and debated in every school and college. It must surely be everybody’s first choice for getting to understand who we are, where we are, and what to do about it. The Last Generation: How Nature Will Take Her Revenge for Climate Change. By Fred Pearce (Random House: Eden Project Books, 2006). ISBN 1 903 91987 8. This book by Fred Pearce, veteran writer on environmental matters, begins by noting ominous signs that people are already feeling the effects of global warming. In 2001, the government of Tuvalu in the South Pacific – its islands disappearing beneath rising sea levels – signed a deal for New Zealand to take refugees; in 2003, the heatwave in Europe left more than 30 000 dead; by 2005, evidence was accumulating of exceptional hurricanes, melting Siberian permafrost, and faster glacier flow on Greenland. People are interfering with the fundamental processes that make the Earth habitable for humans, he writes, but we can still set the planet back on the right course if we act realistically, quickly, and intelligently. This book offers serious grounds for concern – but also some excellent suggestions.
Suggestions … from young readers I am possibly interested in a future career in rocket science and I was wondering if you could elaborate more on the type of rocket fuel used and the process whereby it is burned when used to launch a satellite into space. Grade 12 science student (name withheld), Bryanston. Did you know that in Limpopo you can find the biggest baobab tree? In South America, in the Amazon jungle, you can find the biggest trees? My sister and I would like to read about trees in Quest magazine and study the animals that live in the trees. We like trees because they breathe in carbon dioxide and give out oxygen. Tamás Pinter (aged 9) and Olivia Pinter (aged 6), Westdene. 2. The GreenHouse Project has many supporters, who have helped in cash and kind at various stages. They include Earthlife Africa Johannesburg, the City of Johannesburg, the Danish government (through DANCED, then DANIDA), the National Lottery, Wesbank, Investec, the Department of Environmental Affairs and Tourism, the Gauteng Provincial Department of Housing, the Johannesburg Housing Company. Only with generous help can this kind of project survive and grow.
… from educators Quest asked teachers around the country how they used their copies of the magazine. Here’s what they said Quest helped them to do. ■ Set contextual questions on specific subjects – and for Olympiads and science quizzes
■ Prepare science talks; have science-club discussions; great for debates! ■ Present assembly talks, to make learners (even non-science) to be more aware of their environment and world ■ Find topics to explore further on the internet; useful resource and reference material for research projects and assignments, for exams, for science Expo, and for designing worksheets; good for life-orientation ■ Raise awareness of developments in various fields in scientific research; understand how knowledge in Quest is useful in daily living ■ Source material for comprehension and reading tests, translation activities, and for raising general knowledge levels ■ Supplement textbook information ■ Create displays in the media centre ■ Update educators for the changing curriculum – readable format, magnificent pictures! ■ Arouse enthusiasm – in the learners’ words, “It’s cool!”
Quest 3(2) 2007 43
Q Your Q UEST ions answered
Why such floods? QUESTION Where did the floods in Mozambique in February come from? Why was South Africa spared? How do we find out about tropical cyclones in this part of the world? Answers come from Liesl Dyson. Left: A true-colour image of cyclone Favio just before it reached the coast of Mozambique. The eye of the cyclone is clearly visible in the centre of the system. Note the cloud spiralling clockwise into the eye of the cyclone. In the southern hemisphere, all low pressure systems rotate clockwise, while in the northern hemisphere low pressure systems rotate anti-clockwise. Image courtesy of MODIS Rapid Response Project at NASA/GSFC Left: All the tropical cyclone tracks in the Southwest Indian Ocean between 1985 and 2005. The image clearly shows Madagascar acting as a barrier to prevent many tropical cyclones from moving into the Mozambique Channel.
ANSWER The Mozambican floods that killed some 40 people and displaced 280 000 were caused by tropical cyclone1 Favio, which made landfall on the coast on 22 February 2007. The eye in the centre of the cyclone (in the image above) is a relatively calm area, where the atmospheric pressure is lowest. The minimum pressure that occurred during Favio’s lifetime is estimated to have been 930 hectopascals (hPa). This very low pressure caused Favio to be fierce enough to be classified as an ‘intense tropical cyclone’. A tropical cyclone is ‘intense’ when the surface wind strengths are 110–210 km/h. Tropical cyclones are not rare in the Southwest Indian Ocean. About 10 occur every year during the summer season (November to March) but most frequently in the months of January and February. The statistics show that a tropical cyclone does not make landfall in Mozambique every year, and seldom invades the coast of South Africa – the last time was in 1984, when cyclones Demoina and Imboya caused heavy rainfall over the north coast of KwaZulu-Natal. In February 2000, tropical cyclone Eline moved in over Mozambique and was responsible for widespread heavy rainfall and flooding. In many ways Favio and Eline are comparable. Ian Hunter2 of the South African Weather Service reports that both were classified as ‘intense tropical cyclones’ and both invaded the Mozambican coast on 22 February. Eline crossed the coast approximately 100 km south of Beira and Favio about 250 km south of Beira. Eline weakened as it moved westwards over the southern subcontinent, but was still active enough to cause further heavy rainfall over northern South Africa. Favio weakened rapidly over land and South Africa remained dry. After the devastating floods in 2000, the Mozambique Weather Service acquired two
From Wikipedia: http://en.wikipedia.org/wiki/Main_Page
Left (middle): Diagram showing how a weather radar works. The radio waves bounce off water particles in clouds and are reflected back to the radar dish, where a radar echo shows up on a monitor. A computer measures the time it takes for the waves to reflect back, then uses the time measured to calculate how far the particle is away from the radar transmitter. It also measures the amount of energy reflected back to the radar, and assesses the amount of water (in its various forms) in the clouds. From www.windows.ucar.edu Left (below): The image from the Beira radar in the early afternoon of 22 February 2007. The eye of the cyclone is clearly visible in the south. The green and blue colours show the rain in the cloud bands as the cyclone moved northwards towards Beira. From http://metsys.weathersa.co.za/BR.html
weather radars (radar is the acronym for ‘radio detection and ranging’) to provide better information. The radar transmitter sends out high-frequency radio waves in pulses. Radar is useful to weather forecasters for locating rain and hail and for identifying severe storms and heavy rainfall. Once they see the potential for heavy rainfall, they issue warnings and people are advised to vacate dangerous areas. The South African and Mozambique weather services worked together in
1. A tropical cyclone in the North Atlantic is called a hurricane; in Asia it is referred to as a typhoon. Hurricane Katrina, which caused so much devastation in New Orleans in the USA in August 2005, was classified as a ‘very intense tropical cyclone’. The surface winds in Katrina reached 280 km/h. 2. Ian Hunter is a principal researcher at the South African Weather Service and conducts research into forecasting the height of ocean waves.
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identifying the optimum sites for the new weather radars. One of the radars was placed at Xai-Xai (just north of Maputo) and the other at Beira, some 700 km further north, in central Mozambique. When tropical cyclone Favio invaded Mozambique, the radar at Beira was ideally situated to capture the rain bands in the cyclone. The radar images of Favio are very exciting for meteorologists in Africa, as this is the first time that a tropical cyclone has been captured by weather radar on our continent. Meteorologists will now use these data to investigate further tropical cyclones in Africa, and to be able to predict them even more successfully in future. ■ Liesl L. Dyson lectures in meteorology in the Department of Geography, Geoinformatics and Meteorology, University of Pretoria. Her research is in the area of short-term weather forecasting. For more on tropical cyclones, visit the following sites: www.bom.gov.au/catalogue/warnings/ WarningsInformation_TC_Ed.shtml#Cat ; www.aoml.noaa.gov/hrd/tcfaq/A3.html; and www.weathersa.co.za/References/Cyclones.jsp, and consult “Hurricanes” in Quest , vol. 2, no. 2 (pp.32–33). For more on radar, visit www.windows.ucar.edu and www.metsys.weathersa.co.za
Q Q UEST crossword You’ll find most of the answers in our pages, so it helps to read the magazine before doing the puzzle.
You + Science = Planet Earth : A better place to live! At Stellenbosch University’s Faculty of AgriSciences you will learn how to apply your knowledge of science to the benefit of both people and the earth.
2 Insects such as wasps and hornets (6) 4 It turns cartilage blue (6) 9 Seaweed (5) 10 The L in BOLD (4) 11 SAIAB’s interest in biodiversity (7) 13 Surface scum on molten metals (4) 15 Irresistible to pollinators (6) 16 A cetacean (7) 18 Limit to where the Sun can shine directly overhead (6) 19 International club setting policy for selling petroleum (4) 21 Solitary or social insect of the superfamily Apoidea (3) 23 Saline (5) 25 Cheese-like food from curdled soybean milk (4) 26 A terrestrial focus (10) 28 Items of a floating display (5) 29 Animal or plant living in or off another (8)
1 Stage in a life cycle (5) 3 Tunnel or vent (5) 5 The largest asteroid and the first discovered (5) 6 Red bone stain (8) 7 Component of a wasp’s nest (4) 8 Wasp with a sting (8) 12 Firm flexible connective tissue, embryonic bone (9) 14 The 'first finding' of a scientific species (8) 17 The paths of one body going round another (6) 20 Solar planets remaining (5) 22 --- kob; a prized angling fish, now reduced to 4% of its original population (5) 24 A fishnet that hangs vertically, with floats at the top and weights below (5) 27 Eggs (3)
How do you like the crossword puzzle? Was this one too difficult? Too easy? Just right? Would you like more difficult puzzles as well (with prizes)? Or other kinds? Fax the Editor at (011) 673 3683 or e-mail your comments to email@example.com (mark your message CROSSWORD COMMENT).
South Africa needs well-trained agricultural and forestry experts at all levels to supply our growing population with food and fibre, to ensure that food and food sources are unpolluted and safe, and that the environment is used and managed in ways that preserve it for posterity.
Job opportunities There are wide-ranging and challenging job opportunities in agriculture and forestry, from the most practical to the most high-tech – outdoors, in laboratoria, or in business.
Agricultural and forestry education Our degrees take three or four years to complete. After a bachelor’s degree, you can broaden your career opportunities through postgraduate study.
Admission requirements ● Matriculation exemption/endorsement ● 50% aggregate ● Natural Science or Biology SG: E ● Maths SG: D or HG: E
Exciting careers to consider after finishing your degree at Stellenbosch University ● Conservation ecologist ● Winemaker ● Forester ● Eco-tourism operator ● Entomologist ● Viticulturist ● Entrepreneur ● Community developer ● Animal or plant geneticist ● Horticulturist ● Wood processing specialist ● Quality controller
● Agricultural economist ● Researcher ● Environmental impact assessor ● Plant pathologist ● Extension officer ● Food scientist ● Animal scientist ● Soil scientist ● Consultant ● Water research manager ● Game ranch manager
Closing date for applications: 30 October 2007 Contact our Faculty Secretary (Leon Jordaan) at (021) 808 4833, fax (021) 808 3822, or e-mail firstname.lastname@example.org for more information and visit http://www.sun.ac.za/agric
Careers in S&T Q Want to be an astronaut? The sky is not the limit, says Adrian Meyer.
Prepare for space M any young South Africans dream of travelling into deep space and possibly visiting a planet, but becoming a professional astronaut is complicated and demanding. You need comprehensive training for extra-terrestrial assignments to acquire the necessary ‘ability and skills complex’. Careers in global space, however, are very diverse. Literally more than a hundred professions support every team of astronauts that travels beyond Earth. Working together internationally, many scientists and engineers play an important part in space travel without ever setting foot in a spacecraft. Questions arise, such as: Why explore space? Where is the ultimate barrier to human presence? Space is inaccessible – the cost of going there is high, and it’s a dangerous environment, exceptionally hostile to people, with its lack of atmosphere, extreme cold, and exposure to harmful radiation and high-speed micro-sized particles. There are further questions about spacerelated careers for our emerging scientists, engineers, and astronauts: Is there a future for South Africans in space? Does a career in space science offer value to the community? Valid reasons for South African involvement in space exploration include – ■ the search for resources from other planets ■ advanced space-based research programmes to benefit people – it’s prudent, for example, to learn how to protect ourselves from solar storms, cosmic radiation, and damage to the ozone layer ■ the creation of an early warning system in case an erratic meteor or comet threathens to bring destruction to the Earth ■ national involvement in rapidly developing advanced supersonic and/or hypersonic technologies, which are dictating the fast pace of space exploration. South Africa works with the international space community within a particular development framework, so we need to anticipate requirements and abilities, to prepare emerging space scientists and explorers for their future working environments. Research in a global context, sharing information, and developing critical technologies all make our involvement possible and help the nation to keep up in this important field1.
■ Computer engineering and software development, which are pivotal in space exploration ■ Support staff services, including everyone who works in mission control systems and centres ■ Space medicine and psychology; physical therapy ■ Earth science, astronomy, meteorology, geology, radar engineering, satellite technology, remote sensing, and geographical information systems ■ College and university lecturing in disciplines related to space science.
The Space School’s ‘Lost in Space’ experience in Moon Valley, Namibia, simulates some of the tough conditions associated with space travel. Top: With no plants or water, the location chosen as a Moon base looks like a far-off planet. Survival is not easy here. Middle: A specially designed ‘star wheel’ for showing students the relative positions of stars and planets. Photographs: Attie van Staden Above: Computer-based design for a base on the Moon to accommodate 30 inhabitants. Image: Space School Africa Study Group
Some space-related careers In the era of satellites, robotic probes, lunar outposts, space stations, and missions to planets, the need for expertise has never been greater – and it’s the best possible time to start a career in space science. More and more young women, in particular, are realizing their dreams of succeeding in this realm once ruled only by men. Here are some options. ■ Astrobiology and ergonomics: examine the role of life in the Universe and develop lifesupport systems that help human beings reach and explore other worlds ■ Astronomy, astrophysics, and chemistry ■ Aerospace science: design, build, and test satellites and spacecraft
1. A start has already been made with the building of South Africa’s own soon-to-be-launched earth observation satellite, SumbandilaSat (see Quest, vol. 3, no. 1, pp. 31–35).
46 Quest 3(2) 2007
How to get started As early as possible, gain expertise in relevant science subjects – physics, chemistry, mechanics, robotics, electronics, and in particular mathematics – as high-level technology literacy is a critical requirement. While still at school ■ select a broad career path, such as engineering (for instance, robotics, space vehicle design, communications technology, space medicine, space law) ■ get involved in scientific research on a specific topic ■ participate in international school competitions, to build your personal résumé and establish yourself as an emerging scientist in the Global Space Science Community. Then register at your local college, university, or tertiary training centre, or at a distance education institution, for a postschool programme in the direction of your choice in space-related sciences. Aim high! ■ Adrian Meyer is the Chief Executive Officer of the National Youth Development Trust. He was co-founder of the Trust, of Space School Africa, the International Science Based Competition programme, the Robotics Olympics, and the Junior World Cup for Rocketry in Africa. For more on the work of the National Youth Development Trust and on this area of study, visit www.nydt.org and www.aeronauts.co.za. For information about international science-based competitions that promote careers in aerospace design and problem-solving, visit: http://spaceset.org; http://aero.larc.nasa.gov; http://istf.ucf.edu; www.qomer.com/index_en.htm; www.fpsp.org; www.nydt.org/home.asp?pid=713
Q ASSAf News
Diet, nutrition, and HIV/AIDS The intestines are key to the progression of an HIV infection, reported researchers at an international workshop organized on 22 November 2006 by the Academy of Science of South Africa. The Academy’s Panel on Nutritional Influences on Human Immunity is directing its attention mainly at the twin pandemics of HIV and TB infection. The workshop focused on the role of diet and nutrition in relation to the functioning of the gastrointestinal tract in HIV-infected persons. Three separate disciplines joined forces to create a combined view of fast-moving new discoveries and insights in HIV immunology, inflammatory bowel disease, and the specialized microbiology of the 1–2 kilograms of bacteria that (usually beneficially) inhabit people’s intestines, especially but not only in the colon or large bowel. The outcome was a synthesis of understandings that is not possible through the methods and concepts of single disciplines operating independently. Recent studies of HIV-infected monkeys and people show unambiguously that an acute, new HIV infection is followed within days or weeks by the permanent destruction of a large fraction of the body’s entire stock of a particular kind of immune cell called a memory T cell bearing the CD4 marker (CD4+ T cells). The figure measuring these cells in the blood is referred to as the CD4 count. These bloodborne cells are, however, only a tiny minority of all the cells of this type in the whole body, most by far being normally lodged in the mucosa of the intestines, apparently as part of a massive defensive system protecting the body from pathogenic microbes, foreign proteins, and
allergens coming in with, or as food. This intestinal stock of memory T cells is massively attacked and killed by the virus after an acute new infection, and the rest of the chronic infection history of the person concerned seems just to be the body’s ‘too late and too little’ attempts to replace the lost immune cells in the face of continuous further destruction by the virus population in the intestinal wall. As the virus can infect only activated memory CD4+ T cells, it now seems that the body finds itself in a deadly bind, having simultaneously to combat the virus with its active cellular immune defences, but trying to avoid presenting too many activated cells to lethal new local infection by HIV particles. The workshop discussed new findings in various laboratories, which show that the intestinal mucosa becomes ‘leaky’ to intestinal microbes during the long war of attrition, and that this causes both local and systemic inflammatory responses, which are themselves associated with immune activation (that is, resting immune cells becoming activated and susceptible to HIV infection and death). This leakiness of the mucosal barrier to pathogens and inflammation-causing proteins is now thought to be one of the main drivers of the process by which an HIV-infected person eventually becomes frankly immune-deficient (usually revealed by a low blood CD4 count), and picks up the opportunistic infections typical of AIDS that almost invariably lead to death if not treated with anti-retroviral drugs (ARVs). Speakers at the workshop also described what gastroenterologists know about the causes and drivers of chronic inflammatory bowel disease, which is common in most human populations. It became clear that HIV infection
can now be considered to be one kind of chronic inflammatory disease of the bowel, as described above. This insight could persuade many scientists working in this clinical area to focus on studying intestinal function in HIV-infected subjects, bringing their experience to bear on the problem of lowering the ‘driving’ action of intestinal leakages, thus maintaining best-possible gut function and staving off the collapse of immunity that results in AIDS. A third topic was our rapidly expanding understanding of the nature and role of the specialized intestinal bacteria (now called the human intestinal microbiome), which appear to help their human hosts in different essential ways, yet contain, among their trillions of numbers, subsets of organisms and protein products that must be ‘kept out’ of the body’s tissues by the extensive defensive systems now known to line the entire, highly folded and spread-out gut surface. The microbiome and the gut in fact have a variety of complex mechanisms to ‘control’ each other to keep the body healthy. The workshop began exploring ways in which the deliberate manipulation of microbiota (through administration of so-called ‘probiotic’ living organisms, as found in yoghurt products and/or ‘prebiotic’ food components or additives) may be useful for protecting a bowel under inflammatory attack, as in HIV infection. This offers an entirely new facet of the ongoing interest in diet in helping HIV-infected people to stave off AIDS. The ASSAf Panel’s full report is due to appear later in 2007. It will provide authoritative advice and recommendations on this controversial topic, and much that is conceptually new and relevant at a time of intensive policy debate.
Q Diary of events Cape specials ■ Iziko Planetarium, Cape Town For teenagers and adults, there are Dinosaurs to discover (Mon-Fri at 14:00, excluding 6 & 27 April, 1 & 7 May, 4 & 25–29 June; Tues at 20:00, excluding 26 June; Sat & Sun at 14:30; 27 April and 1 May at 14:30). For stargazers there’s Professor Tony Fairall’s Starfinder Astronomy Course for four consecutive Wednesday nights from 2–23 May. For more phone (021) 481 3900 or visit www.iziko.org.za. ■ South African Astronomical Observatory (SAAO) For updated details of the SAAO tours in Observatory, Cape Town visit www.saao.ac.za/public. For Day and Night tours to SAAO Sutherland (booking is essential), phone (023) 571 2436 or fax (023) 571 1413 or e-mail email@example.com. ■ MTN ScienCentre, Cape Town Visit The Sultans of Science exhibition of great Islamic inventions, which has been extended until the end of April. Join the April Holiday Programme (31 March–15 April) science shows, theatre, competitions, and
hands-on workshops to enthral young and old for hours. For details phone (021) 529 8100 or visit www.mtnsciencentre.org.za.
The world of nature ■ Botanical Society of South Africa Diarize these walks and talks. Insect Walk at the Walter Sisulu National Botanical Garden, Roodepoort (at 09:00 on Sun 15 April); Bonsai lecture with practical demonstration of the creation and treatment of bonsai, at the Nestlé Environmental Education Centre (at 09:30 on Sat 21 April); Black Eagles (with special reference to the Eagles of Toodekrans) at the Nestlé Environmental Education Centre (Sat 5 May). Booking is essential, as numbers are limited. Contact Karen at (011) 958 0529 (mornings) or e-mail firstname.lastname@example.org. ■ The Spider Club of Southern Africa Learn the basics of identifying spiders by joining the Beginners’ Spider Identification Course on 14 April at the Blesbokspruit Nature Reserve, East Rand (to book, contact Ian Engelbrecht on 082 763 4596 or e-mail adustus@
ananzi.co.za OR Astri Leroy on (011) 958 0695 or e-mail email@example.com). Join a Spider Club Long Weekend outing 27 April–1 May in the Southern Free State (contact Danie Smit on 082 418 5869 or e-mail Danie.Smait@improchem.co.za). ■ Peace-of-Eden Book ahead for Wild Women, Wild Dogs and Wild Men at Venetia Limpopo Nature Reserve 28 June–2 July. Contact psychotherapist and ecotherapist Mandy Young on (021) 531 1446, e-mail firstname.lastname@example.org, or visit www.peace-of-eden.co.za.
Get involved ■ Sasol SciFest – South Africa’s leading science festival: Grahamstown, 21–27 March. Phone (046) 603 1106 or visit www.scifest.org.za. ■ International Polar Year (IPY) activities countrywide. The IPY officially began on 1 March 2007 and covers two full annual cycles (to March 2009), involves over 200 projects, with thousands of scientists from over 60 nations examining a wide range of physical, biological, and social research topics. ■ World Environment Day – 5 June.
Quest 3(2) 2007 47
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48 Quest 3(2) 2007
Q Back page science Open minds ■ “In mathematics you don't understand things. You just get used to them.” Johann von Neumann (1903–1957), computer scientist and mathematician ■ “Only the curious will learn and only the resolute overcome the obstacles to learning. The quest quotient has always excited me more than the intelligence quotient.” Eugene S. Wilson (1900–1981), Dean of Admissions, Amherst College Great reads The best science book ever written, as judged in an event organized by the Royal Institution in London, was Auschwitz survivor and chemist Primo Levi’s The Periodic Table (1975). The Guardian (21 October 2006) described it as the “haunting memoir of life as a Jew in Mussolini's Italy, told through the unlikely metaphor of chemistry”. Other contenders were: Konrad Lorenz, King Solomon's Ring; Tom Stoppard, Arcadia; Richard Dawkins, The Selfish Gene; James Watson, The Double Helix; Bertolt Brecht, The Life of Galileo; Peter Medawar, Pluto's Republic; Charles Darwin, Voyage of the Beagle; Stephen Pinker, The Blank Slate; Oliver Sacks, A Leg to Stand On. Ancient secrets ■ Mythology, technology, and biology came together in an unexpected insight when scientists at the Field Museum in Chicago were studying ancient South Pacific pottery. “The strange faces drawn on the first pottery made in the South Pacific more than 3 000 years ago have always been a mystery to scientists,” reported the website Science Daily (14 December 2006). It was thought that they had something to do with ancestor worship. But various kinds of evidence, including folktales and the marks made on the beach by turtles laying their eggs, have now produced the theory that the ‘faces’ represent turtles and that these animals were central to the creation beliefs of the islanders who made the pottery.
■ Old secrets came to light, too, when UK researchers analysed what made ‘Hessian crucibles’ so strong. These are mixing vessels that were used by alchemists and early chemists, made in the Hesse region of Germany in the Middle Ages. For centuries they have been “world renowned because of their ability to withstand strong reagents and high temperatures.” (Science Daily, 23 November 2006) In fact, some scientific discoveries would not have been possible without them. “The researchers reveal, using petrographic, chemical, and X-ray diffraction analysis, that Hessian crucible makers used an advanced material only properly identified and named in the 20th century … an aluminium silicate known as mullite … [which] is extremely resistant to thermal, chemical, and mechanical stresses.” The material is now used in various advanced technologies such as catalytic converters. Doh! Many of the writers for the TV cartoon The Simpsons are former mathematicians, scientists, and computer scientists, and they often work maths into the script. In one episode, where Homer Simpson is wandering in three-dimensional space, a ‘mad scientist’ called Professor Frink tries to pass off the idea of the cube as his own – the “Frinkahedron”. In another episode, a character correctly claims that the last digit of pi at 40 000 decimal places is 1. (Science News Online, 10 June 2006) Coaches who coin it If you tossed a coin 1 000 times, you’d expect it to land on heads about 500 times and on tails about 500 times. Indeed, that would probably happen. You’d also expect that heads and tails would alternate often. But you’re more likely to find that one of the sides comes up again and again for a stretch of time, establishing a lead over the other side. It looks like a pattern. The Guardian (4 May 2006) gives this example of chance in real life: “Even if the outcomes were due to chance alone,
you would see very long periods in which … some football managers became icons, while others faced the sack.” Hit and myth ■ Do dogs have belly buttons? Flip Fido over (if he doesn’t mind) and look hard: it’s there, under the fur, but it’s small and more like a slit than our own round navels. Each puppy is born in its own sac of fluid attached to the placenta by an umbilical cord. The mother bites the cord and opens the sac so the puppy can breathe. The cord soon shrinks to nothing but a small scar. (Gene Mascoli, ScienceIQ.com) ■ Usually, the bitch eats the sac – which brings us to the subject of dog breath. It’s often said that a dog’s mouth is cleaner than a human’s, despite a sometimes dodgy diet. But in fact different species have their own kinds of oral bacteria, so you can’t really compare cleanliness. (LiveScience.com) ■ Another claim to make you gril is that people’s hair and fingernails carry on growing after death. Not so: it’s an illusion created by the fact that skin pulls back as the dead body dehydrates, exposing more hair and nail. (LiveScience.com) ■ More dry facts: it may well be true that if you run in the rain you get less wet than if you walk. It has to do with the number of raindrops hitting your head when you walk compared with those hitting your chest when you run. Or so the mathematicians say. (LiveScience.com)
Answers to Crossword (page 45) ACROSS: 2 Vespid, 4 Alcian, 9 Algae, 10 Life, 11 Aquatic, 13 Slag, 15 Nectar, 16 Dolphin, 18 Tropic, 19 OPEC, 21 Bee, 23 Salty, 25 Tofu, 26 Geocentric, 28 Buoys, 29 Parasite. DOWN: 1 Larva, 3 Shaft, 5 Ceres, 6 Alizarin, 7 Cell, 8 Aculeate, 12 Cartilage, 14 Holotype, 17 Orbits, 20 Eight, 22 Dusky, 24 Seine, 27 Ova.
MIND-BOGGLING MATHS PUZZLE FOR Q UEST READERS Farmer Jim owns a plot and three animals: a cow, a goat, and a goose. Jim discovered the following: when the cow and the goat graze on the field together, there is no more grass after 45 days. When the cow and the goose graze on the field together, there is no more grass after 60 days. When the cow grazes on the field alone, there is no more grass after 90 days. When the goat and the goose graze on the field together, there is no more grass after 90 days also. For how long can the three animals graze on the field together until there is no more grass left?
Win a prize! Send us your answer (fax, e-mail, or snail-mail), together with your name and contact details, by 15:00 on Friday 4 May 2007. The first correct entry that we open will be the lucky winner. We’ll send you a cool Truly Scientific calculator! Mark your answer “QUEST Maths Puzzle no. 2” and send it to: QUEST Maths Puzzle, Living Maths, PO Box 478, Green Point 8051. Fax: 086 6710 953. E-mail: email@example.com For more on Living Maths, phone 083 308 3883 and visit www.livingmaths.com Answer to QUEST Maths Puzzle no. 1. The number is 2592 (25 is 32 and 92 is 81; 32 × 81 is 2592). The winner is Stanley van den Heever from Stellenbsoch.
Quest 3(2) 2007 49
DISTINGUISHED SCIENTISTS CHANNEL THEIR EXPERTISE TO SERVE THE COMMON GOOD
A D V I C E F O R T H E N AT I O N
First Floor, Block C, Building 53, CSIR Campus South Gate, Meiring NaudĂŠ Road, Brummeria, Pretoria 0184 PO Box 72135, Lynnwood Ridge 0040 For details, e-mail: admin @assaf.org.za or visit www.assaf.org.za