Science Science for for South South Africa Africa
Bioenergy an innovative use for wood
ISSN 1729-830X ISSN 1729-830X
Volume 7 • Number 4 • 2011 Volume 3 • Number 2 • 2007 R29.95 R20
Sustainable forestry in South Africa Forestry its role in rural development How strong is that piece of wood?
HIV: a breakthrough by local scientists? The Blombos 'tool kit' more on early modern humans
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Integrated Learning using the Knowledge Network ® IT Learning System
Extracts from multimedia presentations created for the Knowledge Network® United Nations International Year of Forests 2011 Project
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Facts Abou t
Extracts from multimedia school projects and other fun projects
® Learning together, working together
Forestry is not about trees – it’s about people Thomas Seifert Stellenbosch University’s Department of Forest and Wood Science takes us on a journey through South African forestry 4
Converting biomass to energy – a South African perspective Martina Meincken How wood and wood derivatives are contributing to sustainable energy production in South Africa
The value of wood Ben du Toit Scientific management and innovation are driving sustainable production in South Africa’s forests
How strong is that piece of wood?
Contents Volume 7 • Number 4 • 2011
Brand Wessels 26
The use of wood in the construction industry makes it essential that wood strength can be predicted accurately 12
The mathematics behind the transmission of HIV Steve Sherman How to make people think seriously about HIV transmission
Forestry and rural development Cori Ham 34
Forestry plays a vital role in the health of rural communities
What happens to man-made CO2 emissions? Mike Lucas
Where does all the CO2 that our activities produce go?
Breathroughs bring us ever closer to HIV cures 38
Caroline Tiemessen and Patrick Arbuthnot A patient in Berlin may have provided the key to curing HIV 28
Casparus J Crous, Shayne M Jacobs and Kare J Esler South Africa’s rivers play a vital role in conservation
Tool use by early modern humans Shirona Patel 42
Once again, the Blombos Caves are providing insight into early modern human behaviour
Our marine and coastal development will not escape the influences of climate change
United Nations International Year of Forests 2011 – celebrating forests for people
The jury is still out on whether or not acid mine drainage can harm human health, but that is no reason to ignore its potential to do damage
An innovative use of IT and imagination New hope in the fight against HIV infection Quest looks at the latest update on the global HIV pandemic
24 HIV: who would have thought ...? Gillian Arendse It seems that radiation treatment could have unexpected effects on people living with HIV
Acid mine drainage – can it affect human health? Rebecca Garland
Jil Hrdliczka and Knowledge Networks
Climate change and our coasts Nikki James
Conserving our rivers: a meandre along riparian zones
Fact file Where do we need wood?
Science news Bird-like dinosaurs ate birds
Local science ASSAf news – p. 23 • Eskom news – p. 51
Diary of Events
Backpage science • Mathematics puzzle
Quest 7(4) 2011 1
Science Science for for South South AfricA AfricA
Bioenergy an innovative use for wood
ISSN 1729-830X ISSN 1729-830X
Volume 7 • Number 4 • 2011 Volume 3 • Number 2 • 2007 r29.95 r20
Sustainable forestry in South Africa Forestry its role in rural development HIV: a breakthrough by local scientists?
How strong is that piece of wood?
The Blombos 'tool kit' more on early modern humans
Sc A c AAcdAedmeym yo fo fS c I eI eNNccee ooff SS o u u tt hh AAffrrI c I cA A
Images: Ben du Toit, Wikimedia Commons, Department of Forest Science, Stellenbosch University
SCIENCE FOR SOUTH AFRICA
Editor Dr Bridget Farham Editorial Board Roseanne Diab (University of KwaZulu-Natal) (Chair) Michael Cherry (South African Journal of Science) Phil Charles (SAAO) Anusuya Chinsamy-Turan (University of Cape Town) George Ellis (University of Cape Town) Peter Vale (University of Johannesburg) Correspondence and The Editor enquiries PO Box 663, Noordhoek 7979 Tel.: (021) 789 2331 Fax: (021) 789 2233 e-mail: email@example.com (For more information visit www.questinteractive.co.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 Patrick Nemushungwa and back issues Tel.: (012) 349 6624 e-mail: Patrick@assaf.org.za
s this issue of Quest goes to press, the Western world is in financial chaos. European leaders are meeting as I write to try to hammer out a financial deal to save the Eurozone – and specifically Italy’s ailing economy. The figures being bandied about are astronomical – in the billions of US dollars. At the same time that all this money is being thrown at an unsustainable social system in Europe (and the USA) the Global Fund for AIDS, TB and malaria is in financial crisis. Donors are simply not paying – either scaling down their commitments or not releasing money that has been promised – because they are too wrapped up in trying to save their countries economies. This is expected to have a serious impact on southern African HIV treatment and prevention programmes. The local charities and groups that are most affected by this are the Treatment Action Campaign, Médecins Sans Frontières (MSF) and the Budget Expenditure Monitoring Forum. They have met to discuss the extent of the problem. Doctors speaking for MSF have described how they will now have to cancel its round of 11 new grants allocated to various programmes in a number of countries, which will have a major impact on the treatment of diseases such as AIDS, TB and malaria. The latest report of the Joint United Nations Programme on HIV/AIDS (UNAIDS) on the global HIV and AIDS situation is the first truly optimistic one we have had in years. There is real progress in preventing new infections and preventing death in those already infected, through massive antiretroviral treatment programmes. If the continuing financial crisis in Eurpope and the USA results in further cuts to donor funding for programmes such as the Global Fund, then next year’s UNAIDS report will not carry such good news. At the same time reports coming out of the climate change conference in Durban suggest that even more countries will pull out of the Kyoto Protocol for reducing emissions of climate gases. The USA, China and other large climate gas polluters have never been signatories to the agreement and now it looks as though Canada, Japan and Russia may pull out. Again, many of the arguments currently being put forward by large polluters such as the USA for not reducing emissions of climate gases are around the financial recession in the West. It seems that the developing world, and Africa in particular, must continue to suffer from the actions of the rich world. As rich countries discover that their spending levels are unsustainable, so major problems facing the developing world become insignificant in global terms – and the poor suffer. Science may inform those in power around issues such as the prevention of the diseases of poverty and the effects of climate change, but it is economics that determines how the powerful use this information. For more good science see www.questinteractive.co.za
Copyright © 2011 Academy of Science of South Africa
Bridget Farham Editor – QUEST: Science for South Africa Published by the Academy of Science of South Africa (ASSAf) PO Box 72135, Lynnwood Ridge 0040, South Africa Permissions Fax: (021) 789 2233 e-mail: email@example.com Subscription rates (4 issues and postage) (For subscription form, other countries, see p. 56.)
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Design and layout Creating Ripples Graphic Design Illustrations James Whitelaw Printing Paradigm
2 Quest 7(4) 2011
Department of error Quest 7(3):
The Dawn of Humankind Haplogroup L195 should be L1’5. SAIAB News Deploying the ROV – the caption should read: SAIAB’s African Coelacanth Ecosystem Programme conducted its first filming of coelacanths off Sodwana Bay in May 2011. Here, the Seaeye Falcon Remotely Operated Vehicle is deployed from the Motor Yacht Angra Pequena. There were no OTN receivers deployed with the ROV on that cruise, as noted in Quest Vol 7(3) p.46 The OTN project team – the caption should read: The Motor Yacht, Angra Pequena, was used to deploy the ROV used to observe and film coelacanths off Sodwana Bay. The exhibition members shown on board are the ACEP team not the OTN team as noted in Quest Vol7(3) p.46. All material is strictly copyright and all rights are reserved. Reproduction without permission is forbidden. Every care is taken in compiling the contents of this publication, but we assume no responsibility for effects arising therefrom. The views expressed in this magazine are not necessarily those of the publisher.
Forestry is not about trees – it’s about people I
t is important to understand forestry as a service to society and not only as a business. This is a commitment and a challenge at the same time since forestry includes complex ecological, technical and socioeconomic aspects in order to manage natural and man-made forest ecosystems. Nearly everything in forestry is about sustainability –foresters were indeed the first to use the expression ‘sustainability’ and to commit themselves to sustainable management principles in the late 1800s in Europe, when most of their forest resources were exploited and they realised that exploitation must be replaced by sustainable management. Ever since, forestry has worked, based on sustainable management principles. Forestry provides some of the most important sustainable resources: timber, fibres and a large variety of so-called non-timber forestry products, such as the seven weeks fern for floristic use, bark for tanning and medicinal use, pine resin for chemical use, eucalypts for feeding bees for honey production and also a large variety of fruits and mushrooms. Forests are also habitats to many animals and are particularly important for our own regeneration, providing shade, fresh air and a cool balanced climate. Forests also have a vital role to play in soil protection, reducing
Professor Thomas Seifert, Head, Department of Forest and Wood Sciences, Stellenbosch University. Image: Stellenbosch University
the risk of landslides, soil erosion and degradation. Forests are also important for water purification because they slow down water percolation through the soil. Commercial forestry and the downstream wood and paper industry are major contributors of work, particularly in the under-resourced rural areas where the need is greatest. In South Africa an estimated
2.3 million livelihoods depend on this sector. It is important to understand that forests extract CO2 from the atmosphere, store it in their wood and thus reduce our climate gas emissions to the atmosphere. Every piece of wood in our houses is an active contribution to mitigate climate change. Thus, we should work towards a greener society that is based on sustainable resources. Recently concerns were raised about the water consumption of commercial forests. This is a very valid concern in a water-scarce country like South Africa, but if you compare plantations to natural vegetation on the same sites the consumption of forests is not that much greater, so the huge benefits of trees and forests outweigh the negative effects. Forestry Science and Wood Science are committed to delivering the necessary scientific background to work with this wonderful resource in a sustainable way. Both disciplines are meanwhile highly ‘technologised’, using the most modern equipment for, for example, material analysis, simulation and logistic optimisation to meet the challenges of providing a competitive, ecologic and socioeconomically sustainable forestry industry for the people of South Africa and the rest of the continent. ❑
Quest 7(4) 2011 3
Converting biomass to energy – Martina Meincken explains the importance of biomass in providing energy in South Africa.
ith fossil fuels becoming ever scarcer and more expensive, renewable energy options are gaining interest worldwide. In developing countries such as South Africa, where the electricity grid is not yet completely developed, it is more economically viable to expand the grid with renewable energies than with fossil fuels. There is currently a strong drive to develop the solar, wind and bioenergy sector in South Africa. The move from first-generation biofuels (e.g. maize and sugarcane), which were accompanied by problems of food security, to second-generation biofuels, such as lingocellulosic (woody) biomass, is currently being attempted all over the world, although it poses its own problems.
Sugarcane leaves are used as biofuels.
A gasification plant in Europe.
4 Quest 7(4) 2011
Image: Wikimedia commons
Image: Wikimedia commons
The term lingocellulosis refers to plant biomass that is composed of cellulose, hemicellulose and lignin. It is usually grouped into four categories – agricultural residues (including maize and sugarcane leaves and stalks), dedicated energy crops, wood residues (including sawmill and paper mill discards) and municipal paper waste.
In South Africa, for example, wood is a valuable commodity. Not enough is produced for industrial purposes and for energy conversion. Residues are used largely at the production site, e.g. to fire boilers to dry the wood and are therefore not available for further processing. Alternative fuel resources, such as agricultural residues, will have to be found if biomass is to be used for energy production. One possibility is to use the lignin residues of the pulp and paper industry, but at the moment this requires (expensive) pretreatment. Something that has to be remembered is that in South Africa – in common with other developing countries – a large proportion of the population are already using biomass to generate energy, although not in the most efficient ways. Often, this sector of the population is strongly dependent on this energy source, because electricity is not available everywhere. This use of ‘bioenergy’
A South African perspective is frequently accompanied by its own set of problems. Open fires in the house used for cooking and heating often lead to (toxic) smoke inhalation. Volatile organic compounds along with particulate matter (soot) are the cause of many long-term illnesses, informally known as ‘hut lung’. This is a general term that refers to respiratory diseases, such as tuberculosis, respiratory infections and cancer1. If the fire is not tended properly, it often leads to the loss of property and even life. The challenge associated with this level of bioenergy use is to decrease the use of wood obtained illegally from plantations or protected trees and to provide communities with safe and affordable alternative biofuels. More efficient conversion techniques also need to be used. Various initiatives are trying to reduce the need for wood in rural communities by producing briquettes or pellets from wood waste generated by industry and foliage collected from around the houses. Many of these products have a low production cost and can provide an additional income for households2. This article discusses biomass availability and possible conversion techniques with respect to all bioenergy users. On a small scale, this means that the cost factor of any conversion plays a significant role, while on a large scale the actual availability might be more important. Conversion techniques Biomass can be converted into different forms of energy using different conversion techniques3. Direct combustion
The simplest conversion technique is direct combustion, which produces heat. This is used widely in rural areas to heat living areas and cook meals. Unfortunately, this is also the most inefficient conversion technique and a great deal of energy is lost. Combustion can be made safer and more efficient by using more sophisticated reactors, such as closed combustion systems with welldesigned air and flue gas ducts. Gasification
Image: Bridget Farham
biomass in an atmosphere starved of oxygen. It results in the production of heat and a mixture of combustible gases that can be compressed and stored for later use, for example, to cook meals. Certain reactor types can also power turbines, with the excess heat produced in the combustion chamber being used to produce electricity. In Europe — mainly Scandinavia — these plants, which are known as combined heat and power plants, supply entire cities with heat (through underground pipes) and electricity. In South Africa, gasification is currently used by some industries to generate the heat and electricity they need. For example, sawmills use their wood residues to dry wood and run their machinery. Electricity produced in this way is not yet fed into the national grid.
A diagram showing the process of pyrolisis.
The third major conversion technique is pyrolysis, which is the combustion of biomass in the absence of oxygen. Pyrolysis produces solid (often called biochar), liquid (bio-oil) and gaseous components. Depending on the reactor configuration and control parameters, the ratio between these components
Gasification is the combustion of
Areas such as this in the Eastern Cape are severely wood depleted as a result of human activities.
Figure 1: Wood use in Africa in 20074.
Quest 7(4) 2011 5
The Ethiopian highlands have been changed radically by farming activity. Image: Wikimedia commons
can be altered. The bio-oil can be converted into bio-diesel to power engines or vehicles and the combustible gas can be compressed and stored, as for gasification. The simplest form of pyrolysis is commonly used in rural areas to make charcoal in earth mounds. Like open fires in the case of combustion, this is a rather inefficient conversion method that can be vastly improved by using, for example, steel reactors, that allow the reaction temperature and residence time to be controlled. Availability of biomass The largest wood product sectors in developing countries remain fuelwood and charcoal, which are used to provide energy for heating and cooking. Almost 90% of the wood harvested in Africa is used for fuel
(see Figure 1). The demand for wood has a huge effect on forest systems. Deforestation now represents one of the most pressing environmental problems faced by almost all sub-Saharan African nations. Many sub-Saharan countries have had over three-quarters of their forest cover depleted and it is estimated that if current trends continue, many areas will experience a severe wood shortage by 20255. The illegal logging of plantation forests and protected tree species for firewood or coal production poses an additional problem that further diminishes forest systems. It has therefore become vital to expand the application of energy conversion to a wider scope of biomass, such as harvesting and processing residues, agricultural residues or invasive
Wood > 50 mm
5 757 356
6 691 675
Wood 25–50 mm
2 388 852
3 276 640
Branches < 25 mm
1 786 231
1 916 697
1 225 295
1 916 697
2 852 276
11 157 734
14 829 776
Table 1: Estimated green biomass (tonnes) of woody material of different diameter classes and foliage for three species of invasive Australian wattles in the Western Cape, South Africa.
6 Quest 7(4) 2011
plants. South Africa has a considerable number of invasive trees that were mostly imported from Australia (Acacia species) to act as wind breakers or to stabilise sandy ground. It was soon established, however, that these plants deplete the scarce water resources, spread too quickly and pose a threat to indigenous (slow-growing) flora. Most invasive tree species must now be cleared by law in order to prevent bush encroachment and water depletion. Table 1 shows the estimated biomass available from invasive trees in the Western Cape of South Africa6. This biomass would potentially be available for energy conversion. It is particularly important to make these products and techniques available at an affordable price to the rural communities that depend on biomass for energy conversion. Biomass preparation Few gasification or pyrolysis reactors can process heterogeneously-sized fuel. Added to this, few reactors will reach their maximum conversion efficiency. The biomass therefore needs to be prepared, which in most cases requires work including intensive chipping, milling and subsequent
compression to uniformly sized pellets or briquettes (see Figure 2). This is associated with equipment and labour costs and is not always feasible. An additional problem is that not all biomass can be pulverised and compressed equally well to give stable fuel pellets. Agricultural residues in particular can prove to be difficult because they often lack lignin, the natural binder present in wood, which stabilises pellets7. Finally, the biomass should be as dry as possible before it is used for energy production. The conversion of wet biomass is very inefficient because much of the built-in energy is wasted on water evaporation. Optimum moisture content values are between 10% and 20% and therefore most biomass needs to be dried before it can be processed. Biomass properties The energy content is typically thought of as the most important property characterising a biofuel. It depends largely on the density of the biomass as well as the carbon (C), oxygen (O) and hydrogen (H) ratio. The higher the C content, the higher the energy content and the more O and H the biomass contains. More volatile components will be formed when biomass with a higher C content is combusted, which therefore lowers the energy content. The energy content of dry woody biomass is in the range of 18 - 20 MI/kg8, with little difference between species. Several other factors are equally important in deciding whether biomass is suitable for a certain form of energy conversion. These include: n Moisture content: The biomass should have a fairly low moisture content after harvesting. Ideally, air drying should be enough to reach the desired 10 - 20% moisture level in order to minimise processing costs. n Size: The biomass should be homogenous in size (e.g. wood chips or residues, such as grape skins) or at least be easy to pulverise. Several reactor types (e.g. fluidised bed reactors) can be fed directly with chips or small particles, while others require pellets, briquettes or larger pieces of wood. The reactor type should be chosen according to the biomass that will be used and the pulverisation equipment that is available.
Figure 2: Processing steps for wood pellets made from wood (sawmill) residues.
n Biomass composition: Apart from C, O and H, biomass contains nitrogen (N) and sulphur (S). Both can react with O to form toxic components in the flue gas, commonly termed nitrogen oxide (NOx) and sulphur oxide (SOx) These components have a severe negative impact on human health and the environment, e.g. in the form of acidic rain9. For this reason, the N and S content should be as low as possible; n Ash content and composition: Ash is the inorganic part of the biomass that cannot be combusted and its content should be as low as possible. Wood typically has an ash content of < 0.5%, while many agricultural residues can reach 20% and more. The biomass/ash composition has a large impact on its possible further uses, e.g. as fertiliser. It also affects the conversion reactor. Metal oxides (silicon dioxide [SiO2], aluminium oxide [Al2O3], iron (III) oxide [Fe2O3], etc.) lead to slagging (production of fused refuse from the metals), while alkaline metals (potassium chloride [KO], iron (III) chloride [FeCl2], sodium chloride [NaCl], etc.) lead to corrosion of the reactor10. The biomass/ash should therefore have a low Si, Fe, K, Cl, etc., content. Conclusions The conversion of biomass to energy can be done in various ways and on different scales, ranging from the processes in rural households to large industrial plants. In order to make it economically feasible, the following key questions have to be answered: n What type of biomass should be used and how much of it is available? n Which conversion technique will be used and what form of biomass can it handle? n Does the biomass need any preprocessing? n What environmental effect does conversion of the chosen biomass have?
In South Africa, woody biomass will have to be planted especially for energy conversion, or other residues will have to be used, due to a significant roundwood shortage. Alternative biomass sources, ranging from invasive plants to agricultural residues, appear to be a promising solution. The physical and chemical properties — especially of the agricultural residues — have to be determined first, however, to make sure that they are suitable with regards to emissions and processability. This is part of ongoing research in our group and so far many suitable resources for energy conversion have been identified. ❑ Martina Meincken is a Senior Lecturer, Wood Physics and Bioenergy, Department of Forest and Wood Science, Stellenbosch University. Her fields of interest are wood physics, composite materials and bioenergy.
References 1. Boman C, Forsberg B, Sandstrom T. Shedding new light on wood smoke: a risk factor for respiratory health, Eur Respir J 2006;27(3):446-7 2. McDougal 0, Stanley R, Holstein SC. A unique approach to conservation, Chemical Innovation 2001;31:22-8. 3. Faaij A, Modern Biomass Conversion Technologies, Mitig Adapt Strateg Glob Change 2006;11(2):343-75. 4. Food and Agriculture Organization (FAD), State of the world’s forests, 2007. Available at: www.fao.org/docrep/009/a0773e/ a0773e00.htm (accessed 5 January 2011). 5. Energy Information Administration (EIA), Sub-Saharan Africa: Environmental Issues, 2000. Available at: http://worldroom. tamu.edu/Workshops/Africa07/Agriculture-SubSaharan-Africa/ Environmental%201ssues%20in%20Sub% 20Saharan%20Africa. doc (accessed 5 January 2011). 6. Theron IM, van Laar A, Kunneke A, Bredenkamp BV. A preliminary assessment of utilizable biomass in invading Acacia stands on the Cape coastal plains. SAJS 2004;100:123-5. 7. Malatji P, Meincken M, Processing of wood and agricultural waste for gasification, Presented at: the South African Chemical Engineering Conference, Somerset West, 20-23 September, 2009. 8. Gaur S, Reed TB. An atlas of thermal data for biomass and other fuels, National Renewable Energy Lab, 1995. Available at: www. nrel.gov/docs/legosti/old/7965.pdf (accessed 3 August, 2011). 9. Sander B. Properties of Danish biofuels and the requirements for power production. Biomass and Bioenergy. 1997;12:177-83. 10. Baxter LL. Ash deposition during biomass and coal combustion: A mechanistic approach. Biomass and Bioenergy 1993;4:85-102.
Quest 7(4) 2011 7
Harvesting in a sustainably managed eucalypt plantation. Image: Ben du Toit
Science-based management and innovation must drive improved and sustainable production (of newgeneration products) from Southern Africa’s forests. By Ben du Toit
The value of wood S
Pockets of indigenous afromontain forest thrive in Cecilia forest, Cape Town as part of the ecological network. Image: Wikimedia commons
8 Quest 7(4) 2011
outhern Africa has some beautiful and diverse natural forest pockets, ranging from coastal dry shrub forests, through high temperate forests to escarpment forests and dry bushveld, to name but a few well-known forest types. These forests have served the people of South Africa though many centuries with wood for construction, fuel and furniture, while providing shelter and recreation space. However, most of our forests have experienced periods of overexploitation which may have been disastrous for the forest and the people depending on it. Two short examples will suffice: the Southern Cape forests were heavily exploited by indiscriminate felling by forest dwellers in the 1800s and had largely disappeared by the early 1900s. A more recent example is the deforestation of the Dukuduku Forest during the last two decades by poor, landless people trying to eek out an existence. An analysis of the reasons leading up to these disasters reveals several common factors: n Comparatively large numbers of poor, landless people
n The slow growth rate of our natural forests n Over-exploitation of the forest resource by unscientific management.
Managing forests In several places, this downward spiral has been broken by sound, scientific forest management. For, example, in the Southern Cape it has taken the form of controlled utilisation of the natural forests and, importantly, the introduction of the plantation forests to supplement wood production. Today, the country has a well-developed and scientifically managed plantation resource, which occupies about 1% of the country’s surface area, but supplies the lion’s share of the country’s wood resources on a sustainable basis. The most commonly planted genotypes are fast-growing pine and gum species and their hybrids. The growth rate of the plantation species exceeds that of the natural forests by at least 20 times and great care is taken to ensure that forest management practices are sustainable in the long term. Equally important is the fact that the plantations are being managed in such a way that large environmental networks remain in the
Final year forestry students, Stellenbosch University.
Surviving indigenous forest near Nature’s Valley, Garden Route.
Image: Ben du Toit
Image: Wikimedia commons
The value chain of wood.
Pinus oocarpa trees are commonly used as pollen donors to breed disease-resistant pine hybrids. Image: Ben du Toit
form of corridors (e.g. riparian zones, buffer zones for fire protection, etc.) and this network has been shown to be pivotal in the conservation of biodiversity at the landscape scale (Samways et al, 2010). Hydrological research over several decades has shown that all this is achieved with national average stream flow reduction of just under 4% in afforested catchments (Jewitt, 2002). More than 80% of the country’s plantation forests have been certified by independent assessors as being managed on an economically sound, environmentally sustainable and socially equitable basis (Forestry South Africa, 2009). South African forestry can therefore be regarded as responsible, renewable, sustainable and a highly productive value chain in the southern African economy. The future However, there is no time to become complacent. With a rapidly growing population in southern Africa, and the realisation that we are too dependent on non-renewable energy sources, wood production has again taken centre stage during the last few decades. People in the region (and indeed also in the world) are not only looking towards
forests for increasing production of raw materials for ‘conventional’ uses (e.g. solid wood, pulp and paper). The focus is broadening to include biomass for energy generation and the construction of bio-refineries to extract an array of chemical compounds for industrial use. Increasingly, all this has to be sourced from clean energy sources such as sustainably managed plantation forests, to decrease environmental destruction and global climate change. There is also scope for intensified harvesting of high-value timbers and forest products from the region’s natural forests, as long as this is also done on a scientific and sustainable basis to avoid some of the poor choices of the past. Looking at the next half century – which clusters of expertise will be needed to ensure increased, but sustainable production of wood products, energy and industrial chemical derivatives in the forest value chain? n People with genetic, biological and environmental expertise pertaining to forestry n People with forest engineering and logistical expertise n People with forest planning, management and economic skills n Wood scientists with chemical,
engineering and microbiological expertise. Through investment in the forest value chain, southern African economies have an opportunity to provide sustainable employment to a large number of people in an industry that is environmentally sustainable and has the potential to reduce our reliance on fossil-based fuels. However, the most important investment in this value chain remains the investment in human expertise to drive this process. ❑ Dr Ben du Toit is a senior lecturer in the Department of Forest and Wood Science, Stellenbosch University. His fields of interest ares of planted forests, forest nutrition, stand eco-physiology and site productivity studies, forest soils and ecological sustainability, fire and fuel load management, and bio-energy potentials. References FSA. Abstract of South African Forestry Facts for the Year 2007/8. 2009. Forestry South Africa, Pietermaritzburg, South Africa. 1 pp. Jewitt, G. The 8%-4% debate: Commercial afforestation and water use in South Africa. Southern African Forestry Journal. 2002. 194:1-5. Samways, MJ, Bazalet, CS and Pryke, JS. Provision of ecosystem services by large scale corridors and ecological networks. Biodiversity Conservation. 2010. 19:2949-2962.
Quest 7(4) 2011 9
How strong is that piece of wood? Wood has many uses, and in the construction industry it is important to know how strong a piece of wood is before using it. Brand Wessels explains how to predict the strength of a piece of wood.
Figure 1: Sawn timber use in South Africa in 2010 (Crickmay and Associates, 2010).
Figure 2: A three-point bending test comparison between carbon steel and clear pine will show that the wood can, on average, withstand a four times higher load!
ne of the interesting projects that wood scientists at Stellenbosch University are currently involved in is the nondestructive prediction of wood strength. Wood is a very popular building material in South Africa, where more than 60% of all our sawn timber is used for building or construction purposes. One of the main reasons for this is the high strength of wood. Wood is a remarkably strong material, especially on a strength-to-weight basis. If, for example, the bending strength of a carbon steel rod and a clear knot-free pine wooden rod of the same weight are compared, you might be surprised by the result. On average the wood will be able to withstand a four times higher load than the steel! The problem with wood, however, is that if you repeat the bending test four times with four different pieces of wood you might get very different results for each piece of wood. Although the wood will be on average four times stronger
Table 1: Wood properties measured on each of 396 SA Pine boards Wood property
X-ray densitometry as well as manual determination of volume and weight
Knot properties: Size Position Frequency
A commercial timber scanner with X-ray, laser, and optical sensors was used to scan each board and determine the knot properties (see Figure 3)
The natural resonance frequency of each board was determined by inducing a stress wave with a hammer in the timber and measuring the resonance frequency with frequency analysis software. From this, the wave speed and the dynamic modulus of elasticity (MOEdyn) could be determined (see Figure 4)
Stiffness or modulus of elasticity (MOEstat)
The stiffness or static modulus of elasticity (MOEstat) of each piece of timber was determined using a four-point bending test
Table 2: Measured wood properties and the percentage of variation in bending strength explained by each Wood property used to predict bending strength
Percentage of the variation in bending strength explained by the measured property (R2 value)
Density 39.6% Knot parameter (calculated parameter from the most influential knot)
MOEdyn (calculated from natural resonance frequency of timber)
MOEstat (stiffness or modulus of elasticity calculated from a bending test)
Combination of density, knot parameter, and MOEdyn 62.6%
10 Quest 7(4) 2011
than the steel, some pieces might only be twice as strong and other pieces may be six times as strong. For engineers and designers of structures this variability in strength poses a serious challenge: What strength values does one use to design a wooden structure? In practice, sawmills in South Africa use visual grading of timber to separate timber into groups of similar strength properties. With this type of grading the knot properties of every piece of timber are visually assessed by an operator and, based on specific knot size and position criteria, the piece of timber is graded. This method, however, is a fairly poor way of assessing wood strength properties. Research has shown that visually assessed knot properties can only explain between 15% and 35% of the bending strength properties of wood. In a recent research project at the Department of Forest and Wood Science at Stellenbosch University, a number of other wood properties of South African Pine (the group name for South African grown Pinus radiata, Pinus patula, Pinus elliottii, Pinus taeda and Pinus pinaster) were non-destructively measured and related to the bending strength of the timber. The properties were measured on 396 boards from a single sawmill. These measured properties are listed in Table 1. An elastic modulus, or modulus of elasticity, is the mathematical description of an object or substanceâ€™s tendency to be deformed elastically (i.e. non-permanently) when a force is applied to it.
Some of the results collected in this project are summarised in Table 2 and illustrated in Figures 6 - 9. From the results it is obvious that it is quite difficult to accurately predict bending strength of the wood with any of the determined parameters. None of the properties showed a very high correlation with bending strength. However, if one considers that the current method used in sawmills (visually evaluating knot properties) can only explain between 15% and 35% of the variation of bending strength, all the alternative methods evaluated here proved to be far superior. The individual property that
Figure 6: A scatterplot with linear regression to illustrate the relationship between wood density and bending strength. Figure 3: A picture of a board containing knots and the computer reconstruction of the board after X-ray scanning of the timber.
Figure 4: Acoustic resonance frequency determination. Figure 7: A scatterplot with linear regression to illustrate the relationship between the knot parameter and bending strength.
Figure 5: Destructive four-point bending test.
explains bending strength the best was the stiffness or static modulus of elasticity (MOEstat). On a practical level this method can be implemented in a sawmill by subjecting each board to a bending test where one measures the deflection of the timber when only a small load is used (in other words the timber is not broken, only bent and released). Machines exist that do this at great speed and accuracy. Where a combination of three of the above properties (density, MOEdyn and a calculated knot parameter) were measured, the strength prediction could be improved to a level of 62.6%. Commercial machines which can measure these properties in a
production setup have also been developed recently. These machines use a variety of sensors to scan each piece of wood at fairly high speeds. From the results it can be concluded that although it is a challenge to accurately predict the strength of SA Pine in a non-destructive way, it is possible to improve significantly on the current practice of visually assessing timber. â?‘ Brand Wessels is a lecturer in the Department of Forest and Wood Science at Stellenbosch University. His fields of interest are wood mechanics and wood products manufacturing, sawmill processing, and solid wood processing and optimisation.
Figure 8: A scatterplot with linear regression to illustrate the relationship between dynamic MOE and bending strength.
Figure 9: A scatterplot with linear regression to illustrate the relationship between static MOE and bending strength.
Quest 7(4) 2011 11
Most forests are in rural areas. Cori Ham explains how forestry can play a role in rural development.
Forestry and rural development T
he impact of forests on people is well recognised, with more than 1 billion people worldwide depending on forests for their livelihoods. We know that forests offer numerous benefits to nearby communities and society at large – wood for fires and building, employment, ecological services and even spiritual needs. Most forests, by their very nature, are within rural areas that are often remote. These areas often have poor infrastructure, lack government services, are far from markets and jobs and offer limited opportunities to make a living. This is also the case in South Africa, where forestry activities take place in some of the poorest rural areas. It is then not surprising that government has identified the forest sector as an important element of local natural resources development that can contribute to better living environments and economic opportunities. Forestry and value-adding industries have a place in local development programmes in many rural districts in the Western Cape, Eastern Cape, KwaZulu-Natal, Mpumalanga and Limpopo Province. Commercial forestry: an opportunity for development South Africa’s commercial forestry industry contributes significantly to the national economy. From a resource base of approximately 1.27 million hectares of plantations it contributes approximately R20.4 billion per annum to the national economy off a capital base of R25 billion. To make sure that there is an equitable distribution of benefits from this industry, government recently launched a multi-stakeholder initiative to formulate a Forestry and Forest Products Sector Broad-Based Black Economic Empowerment Charter (BBBEE). The goals of BBBEE fit with the goals of poverty reduction, and allow for much greater involvement of previously disadvantaged individuals (PDIs) in the economy. This occurs through equity transfers, and also through enterprise development, employment equity, skills development and training.
12 Quest 7(4) 2011
The most significant contribution that forestry can probably make towards the reduction of poverty is through the creation of employment and business opportunities within forestry areas. It is estimated that there are 96 500 people employed in forestry operations, of which 66 500 people are formally employed, and a further 30 000 are small growers and their helpers. Plantation forestry provides 8.9% of the total number employed in agriculture and 5.6% if small growers and their employees are excluded. These beneficiaries tend to be unskilled, in low-income areas, and with few alternative opportunties to generate income. There are also employment opportunities in secondary and tertiary processing. In 2009 there were 192 processing plants associated with plantation forestry, which provide further employment opportunities through their products. The informal sector South Africa is a net exporter of value-added forest products, with a total export of R12.5 billion per annum. The forestry industry contributes 0.9% to the gross domestic product (GDP) and 9.7% to the agricultural GDP. But there are not only opportunities in the formal sector. In South Africa, timber outgrower schemes allow participating households to increase their income substantially. Gross annual revenue from the sale of timber by small-scale and other PDI growers is estimated at approximately R115 million per year. If you consider that 65% of the revenue from timber sales (approximately R5 million a year) is returned to the communities that grew the timber, this offers an annual average revenue per grower of R3 000 per year over the rotation period, which is often returned in lump sum payments at the end of the rotation. Forest goods and services Forestry provides not only jobs and income in rural areas but also the direct-use benefits of forest goods and
Opposite page (left): A forestry worker stripping eucalyptus bark. Image: Department of Forest Science, Stellenbosch University
Opposite page (right): Commercial forestry provides employment opportunities. Image: Department of Forest Science, Stellenbosch University Above: Some of the employment opportunities are indirectly related to forestry. Image: Department of Forest Science, Stellenbosch University Above right: Sawntimber entrepreneurs. Image: Department of Forest Science, Stellenbosch University
Right: Natural forest fruits being sold. Image: Department of Forest Science, Stellenbosch University
services, including supplying basic needs, saving cash resources and buffering or safety nets during hard times. Two of the most important direct-use benefits are the supply of fuelwood to rural households and the collection of timber and non-timber forest products from forests. In some regions of South Africa up to 80% of rural households use wood for energy in the home, with or without other fuels. Women in these households often walk long distances to fetch firewood. The average time spent this way is estimated conservatively at five hours per household per week. Between 9 and 11 million tons of wood are used for fuel every year, of which about 6.6 million tons are estimated to be harvested from natural woodlands. Fuelwood consumption per household in the Kentani area of the Eastern Cape, for instance, was estimated at 3 700 kg per annum. The commercial role of fuelwood can also be significant when community members supplement their incomes by selling fuelwood. Sometimes this activity becomes their main source of cash – particularly for many landless rural people. Construction Timber for construction is also a major forest product. Up to 15 000 poles from DWAF-managed woodlots in the Eastern Cape are sold annually to nearby communities for building material. In the absence of poles from woodlots, households rely on natural forests for access to building poles. This could have a significant impact on indigenous forests when preference is given to poles from certain age classes of high-demand species. Non-timber forest products Non-timber forest products (NTFPs) include products used for energy, shelter, food and medicine. This allows rural households to use their limited money for other needs such as education, investment in agricultural tools, capital for income generation activities, etc.
The benefits of forest products are not restricted to household use and ‘free’ forest goods. Forest products are also traded extensively and contribute to rural household incomes. For example: n At least 4% of rural households are trading one or more forest products. n There are at least 800 000 people involved in the craft industry. n There are 15 000 people in the Eastern Cape alone dependent on small-scale sawmilling. n There are at least 3 500 households engaged in various forms of income generation from Sclerocarya birrea fruits (marulas), supporting over 20 000 dependants. Forestry is a major source of income and employment in some of the poorest rural areas in South Africa. The formal forestry industry, in partnership with NGOs and goverment, plays a major role in poverty alleviation in these areas. (The information in this article was taken from a number of sources.) ❑ Cori Ham is a lecturer in the Department of Forest Science, Stellenbosch University. His interests are in forest management, economics and policy and forestry business management and strategy.
Quest 7(4) 2011 13
Research that can change the world
Impact is at the core of the CSIR's mandate. In improving its research focus and ensuring that it achieves maximum impact in industry and society, the organisation has identified six research impact areas: Energy - with the focus on alternative and renewable energy. Health - with the aim of improving health care delivery and addressing the burden of disease. Natural Environment - with an emphasis on protecting our environment and natural resources. Built Environment - with a focus on improved infrastructure and creation of sustainable human settlements. • Defence and security - contributing to national efforts to build a safer country. • Industry - in support of an efficient, competitive and responsive economic infrastructure. • • • •
Where do we need wood? By Martina Meincken
Most furniture is made of wood.
Rough natural paper.
Image: Wikimedia Commons
Image: Wikimedia Commons
ood is a big part of our lives and it can be found all around us, although you might be surprised by some of its uses. First there are the obvious structural uses: roof trusses, support beams, wall cladding, etc. Entire houses can be made of wood. Then there are fences, decks, telephone and electricity poles, walkways and many more things that are made from wood and that play a big role in our daily life. Another big user of wood as a raw material is the paper industry. Wood gets broken down in single fibres, which are then compressed into paper. We all use plenty of it every day! Paper types range from toilet paper over writing paper to cardboard boxes for packaging. More and more we see new products made from a combination of wood and (recycled) plastic, for example, park benches, rubbish
bins, etc. Especially in Africa and other developing regions, wood is still the major source of energy – it is used for cooking and heating in the form of firewood, charcoal and other processed forms, such as pellets or briquettes. There is also a large sanitary market – from nappies to hand towels, everything is made from cellulose, because it has good waterabsorbing properties. These are the obvious uses, but wood or its constituents play a much larger role in our lives: towels and other fabrics (rayon) are made from cellulose fibres, as well as cigarette filters. The strong fibres are used to reinforce the rubber in car tyres and to make tea bags. Cellophane, a form of ‘plastic’ foil, and celluloid, the material of photographs and films until 1930, are made from this natural
Cellulose fibres from a hemp plant.
Image: Wikimedia Commons
polymer. In many cases cellulose is used as inactive filler material in tablets or as thickener in many processed food types, such as Kraft’s tube parmesan. Cellulose is also the raw material for nitrocellulose – a gun powder! Nitrocellulose is also part of many lacquers, inks and undercoats.
Bird-like dinosaur ate birds More than 120 million years ago at least one dinosaur was feasting on a bird. A fossil Microraptor gui from northeastern China — still a dinosaur despite winglike feathers on all four limbs — has bird bones in its abdomen, report Jingmai O’Connor and her colleagues at the Chinese Academy of Sciences in Beijing. The position of the bird feet and partial wing suggest the dinosaur swallowed some now-extinct, tree-perching bird whole, the researchers contend in a paper published online on 21 November in the Proceedings of the National Academy of Sciences. They propose that Microraptor frequented trees and hunted deftly enough to snag what was probably an adult bird. Possible, but not the only possibility, cautions paleontologist Jerry D Harris of Dixie State College in St. George, Utah. If the dino caught its lunch, he wonders why there weren’t more bird bones. Also, studies of Microraptors and their relatives suggest ground-based hunting. Today’s cats certainly get into trees, and perching birds visit the ground, Harris says, but ‘bird remains in a cat’s guts don’t mean that it was hunting and catching birds in trees’.
Quest 7(4) 2011 15
United Nations International Year of Forests 2011
– celebrating forests for people Jil Hrdliczka, of Knowledge Networks, tells Quest about school students’ innovative approaches to sustainability.
Above: Grade 7 learners Katherine Redding and Sonal Kalidas cannot imagine school life without the cool shade of the many trees at St Katharine’s School. Image: Knowledge Networks Left: Kayla Liversage’s PowerPoint presentation slides.
ot a day passes without a child in a school somewhere in the world daydreaming about forests – the warmth of the filtered sunlight on your face, the clouds resting on the canopy, the cool mist from the spray of a waterfall, the hint of a rainbow, the freshness of the air, rich with the smells of life, the gentle sway of fern fronds, the sound dry leaves make when you walk on them, the connection a forest creature makes with you when your paths cross, the whistles, calls and signals of exotic birds, the silence, calm, comforting memories of good times shared, the thought of adventure, of being re-energised and feeling truly alive. The United Nations International
16 Quest 7(4) 2011
Year of Forests 2011 is about people. It is about celebrating forests for people. The United Nations’ web site ‘It’s your World’ provides a global platform to celebrate people’s action to sustainably manage the world’s forests. The United Nations General Assembly declared 2011 as the International Year of Forests to raise awareness of sustainable management, conservation and sustainable development of all types of forests, in other words keeping the forests alive for people. On the United Nations Year of Forests web site, there is a message – ‘tell us how you plan to celebrate forests for people during 2011 so that we may showcase your stories and initiatives through this web site’. For the Grade 7 learners in schools in South Africa implementing the Knowledge Network IT Learning System, this message from the UN was all that was needed to confirm that they have a voice, a chance to make a difference and an opportunity to turn daydreams into action. Action was in the form brainstorming sessions with educators, research, dialogue on forests, using the computer tools they love to present their ideas and packaging their work into viewable and motivating slides. All the work was done in the hope that investors and stars
such as Richard Branson, Warren Buffet, Bill Gates and Leonardo DiCaprio, while surfing the net, may find the work and be inspired by the ideas on making forests man’s real or virtual playground and in return saving the forests and 80% of our terrestrial biodiversity. The Knowledge Network/United Nations International Year of Forests Project involved selecting a forest and research on the environment, people, animals and plants. Maria Luchies, the Computer Skills teacher at The King’s School West Rand said, ‘The learners then had to come up with their own idea on how to save their forest. The impact on the environment had to be minimal and animals had to remain wild. The learners had to think of how their idea would start and how they could grow it, constantly being reminded that their idea should be able to raise funds which could then be used to finance further phases of their idea’. ‘As part of integration with their other subjects, the learners had the opportunity to present their slides and do a speech as if they were presenting their ideas for real. Other teachers and visiting teachers asked questions and the overall interaction and learning that took place was phenomenal,’ said Maria. Kayla Liversage, a learner at The
Katherine Redding working with mentor Linda van der Walt in the computer centre at St Katharine’s School. Image: Knowledge Networks Right: Ernesto Jardim’s PowerPoint presentation slides.
presents itself again, hopefully, I would, without a doubt, do it again.’ There is no question that forests are big business. In 2004, trade in woodbased forest products was valued at US$327 billion. Global trade in nonwood forest products such as bamboo, mushrooms, game, fruit, medicinal plants, fibre, gums and resins has recently been estimated at approximately US$11 billion per annum. More than 50% of the most popular prescribed drugs in the United States are derived from natural forest-based compounds (Groombridge and Jenkins 2002). The trade figures quoted are from a 2007 report on changing trends in forest products trade and from the United Nations web site. The economic value of social, leisure, educational, environmental and medicinal products and services derived from forests is difficult to estimate but is surely on the increase. The crucial economic and environmental role forests play as a carbon reservoir and sink for mitigating climate change has yet to be evaluated or fully understood. Linda van der Walt from St Katharine’s School said ‘through collaboration with each other and with me, the girls were able to come up with exciting ideas to sustain a forest and to piece their presentations together with content, graphics and ideas. As the mentor for the class, I tried hard to inspire the girls to come up with new and exciting ideas’. ‘At first, the concept (of this project) was quite daunting. We all went to the school’s auditorium and discussed what sustainability means and why it is important to make our forests sustainable. The girls split themselves into groups and brainstormed various ideas. The girls’ response to this process was positive and each group was excited to share its ideas with the others,’ said Linda. ‘The girls spent time in the computer centre to research different
kinds of forests and to choose a topic that appealed to them. They enjoyed researching the topics and loved preparing a PowerPoint presentation that drew on all the skills they have learnt over the years. They were also motivated to use graphics in a creative way and they made every effort to ensure that their graphics were relevant to the information on each particular slide,’ said Linda. The United Nations International Year of Forests is about celebrating forests for people. The words used by the United Nations in their message about the Year of Forests invites an entrepreneurial approach and challenged the learners to
King’s School, West Rand, said she enjoyed the project very much because ‘you learn so much that you’ve never put into perspective before. The research was hard, because obviously, you need to find the easiest information to understand, but you also need information that makes you want to go and do something about the continuous problem (of deforestation)’. The United Nations states that forests cover 31% of the Earth’s total land area. Primary forests account for 36% of forest area. It is clear that ongoing positive action is required to maintain these figures and possibly increase the figures over time. Wild forests and forests that are used for the production of wood products are required; 30% of forests are used for the production of wood and non-wood products. Halima Beale, an educator at Helderberg Primary School, said that during the brainstorming sessions the roles that the Earth’s forests play were discussed, from the obvious oxygen production to the lesser acknowledged, but equally important homes of indigenous peoples. The United Nations states that forests are home to 300 million people around the world and that the livelihoods of over 1.6 billion people depend on forests. ‘It was very important to me that the students understood the need for logical thinking and how, even by starting small, they could make a huge difference in the long term. They were able to come up with amazing ideas from creating reserves to rainforest pharmacies where tourists could be taught by the indigenous people in the medicinal uses of plants that are all too often overlooked and destroyed along with acres and acres of trees every minute,’ said Halima. Ernesto Jardim, a Grade 7 learner at Helderberg Primary School, enjoyed the entrepreneurial aspect of this project. ‘I thoroughly enjoyed inventing my own organisation. And when the opportunity
Quest 7(4) 2011 17
Sonal Kalidas’s PowerPoint presentation slides.
Katherine Redding’s PowerPoint presentation slides.
package their projects into products through which their ideas could be marketed to viewers. Linda says that this project differed from those covered during previous years as there was a component that required the use of personal ideas rather than just pure research. Through this project participants learnt that ideas need to be sold through easyto-understand text, emotional wording to connect with the viewer, such as a shared memory or promise of a pleasant experience, and appealing graphics that look professional, complete, balanced and inspiring. They learnt that using colour is important – blues and greens
18 Quest 7(4) 2011
to create a feeling of calm or reds and oranges for warmth or to remind viewers of the beauty of forests in their full autumn splendour. Katherine Redding, a Grade 7 learner at St Katharine’s School, explained her motivation for her presentation package. ‘I have always loved the idea of being in the clouds and, when I had the opportunity to complete a project about a forest in the clouds, I was very inspired and excited. Throughout the project, I wanted to create the effect of being in the clouds and this prompted me to use a blue and green colour scheme for my presentation. I have also loved the idea of flying, so a lot of my information and pictures are about birds. I wanted to create a sense of stability and balance to match the trees and what takes place in a forest. Creating my own tree using PowerPoint’s autoshapes was probably the hardest part of the project because I became obsessed with getting it just right. However, I enjoyed working in a group in which we brainstormed ideas of how to sustain forests.’ Sonal Kalidas, also a Grade 7 learner at St Katharine’s School, said that at the start of the project the Grade 7 class discussed the meaning of sustainability. ‘I tried to be different by not choosing a particular type of forest and decided to focus on a small forest in Japan because it is remote and many people don’t know about it. All the time I was putting my presentation together, I kept thinking about forest trees, green and sustaining life. These thoughts inspired me to use the images in my presentation.’ ‘The bare trees at the bottom of my slides were drawn to create the idea of growth. I tried to keep this idea consistent throughout the project by placing the trees on every slide. I used all the skills that I have learnt in my weekly computer lessons to put this project together in a way that I think best communicates my ideas on how to sustain this forest,’ said Sonal. The United Nations International
Year of Forests 2011, celebrating forests for people, based on the presentations submitted by the Grade 7 learners to Knowledge Network, has achieved its objective. The learners’ action to sustainably manage the world’s forests is being celebrated. We are raising awareness on sustainable management, conservation and sustainable development of all types of forests. We are giving our learners a voice and a chance to make a difference. We are telling our stories and initiatives. We are creating an environment for dialogue on forests and building a solid foundation for awareness, lifelong learning and appreciation of all that forests have to offer. Most importantly, we are not looking at forests in isolation. Forests are not only about trees. Forests are about people, biodiversity, about science, the seasons, life cycles, about the buying and selling of products, about colours, livelihoods and homes, medicines and about looking at a potentially negative topic such as deforestation and turning it into positive action about sustaining life. Forests are also about learning together and working together, about brainstorming, sharing, building an organisation, selling ideas, preparing speeches, working with graphics on the computer, obeying copyright rules, communication and having a choice. From the many quotes received from learners about the Knowledge Network/ United Nations International Year of Forests 2011 Project, we have learnt that forests are also about memories of fun times with the family, adventure, wildlife, ideas, beautiful visions, hope and daydreams. ❑
New hope in the fight against HIV infection The latest report by UNAIDS shows that global efforts to reduce the rate of HIV infection are having some effect. Quest looks at the latest information.
s this issue of Quest goes to press the Joint United Nations Programme on HIV/AIDS (UNAIDS) report shows that 2011 was a game-changing year for the AIDS response with unprecedented progress in science, political leadership and results. The report also shows that new HIV infections and AIDS-related deaths have fallen to the lowest levels since the peak of the epidemic. New HIV infections were reduced by 21% since 1997, and deaths from AIDSrelated illnesses decreased by 21% since 2005. According to UNAIDS and World Health Organisation (WHO) estimates, 47% (6.6 million) of the estimated 14.2 million people eligible for treatment in low- and middle-income countries were accessing lifesaving antiretroviral therapy in 2010, an increase of 1.35 million since 2009. The 2011 UNAIDS World AIDS Day report also highlights that there are early signs that HIV treatment is having a significant impact on reducing the number of new HIV infections. At the end of 2010: n There were 34 million people globally living with HIV n There were 2.7 million new HIV infections in 2010 n And 1.8 million people died of AIDS-related illnesses in 2010. Treatment has averted 2.5 million deaths since 1995 People living with HIV are living longer and AIDS-related deaths are
declining because of antiretroviral therapy. Around 2.5 million deaths are estimated to have been prevented in low- and middle-income countries due to increased access to HIV treatment since 1995. Progress in HIV prevention New HIV infections have been significantly reduced or have stabilised in most parts of the world. In subSaharan Africa the number of new HIV infections has dropped by more than 26%, from the height of the epidemic in 1997, led by a one-third drop in South Africa, the country with the largest number of new HIV infections in the world. In the Caribbean, new HIV infections were reduced by a third from 2001 levels. Similarly the number of new HIV infections in South and South-East Asia dropped by more than 40% between 1996 and 2010. In India new HIV infections fell by 56%. However, the number of new HIV infections continues to rise in Eastern Europe and Central Asia, Oceania and Middle-East and North Africa, while it has remained stable in other regions of the world. The rate of new HIV infections in urban Zimbabwe fell from almost 6% in 1991 to less than 1% in 2010. Without changes in behaviour, studies estimate that there would have been an additional 35 000 new infections annually. The report highlights that
an increase in uptake of male circumcision is also starting to contribute to declines in new HIV infections. Studies show that 2 000 new HIV infections were averted among men in Kenyaâ€™s Nyanza province after scale-up of voluntary male circumcision. Estimates in the report highlight that circumcising 20 million more men across eastern and southern Africa would avert around 3.4 million new HIV infections by 2015. Around 400 000 new HIV infections in children are estimated to have been averted since 1995 due to increased access to effective antiretroviral regimens in low- and middle-income countries by 2010, almost half (48%) of all pregnant women living with HIV were able to access effective regimens to prevent their child from becoming infected with the virus. Investing in health At the end of 2010 around US$15 billion was available for the AIDS response in low- and middle-income countries. Donor funding has been reduced by 10% from US$7.6 billion in 2009 to US$6.9 billion in 2010. In a difficult economic climate the future of AIDS resourcing depends on smart investments. To rapidly reduce new HIV infections and to save lives, the 2011 UNAIDS World AIDS Day report underscores that shared responsibility is needed. â?‘
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Breakthroughs bring us On 9 November 2011 Professors Caroline Tiemessen and Patrick Arbuthnot presented the Sixth Wits Faculty of Health Sciences Prestigious Research Lecture, titled ‘From target discovery to novel treatment for HIV-1’. In this article they discuss revolutionary research and breakthroughs in the approach to HIV.
CCR5: an important target molecule
Towards finding HIV cures, a new body of research on HIV-resistant individuals within the genetically diverse sub-Saharan population is being undertaken. Featured here are three boys from a rural village in South Africa. Image: Jackie Roseleur
How HIV infects a cell. To infect a cell, HIV envelope protein (gp120) or Env interacts with the CD4 receptor as well as either CCR5 or CXCR4 co-receptors on the surface of target cells. Viruses that require CCR5 (R5 viruses) are not able to establish an infection when this co-receptor is absent. Interestingly, mutations in the CCR5 gene have been described which give resistance to HIV infection. A 32 base pair deletion, which results in lack of CCR5 surface expression, is the best described CCR5 mutation. SDF-1 (stromal derived factor-1) is the natural binding factor or chemokine that binds CXCR4, the co-receptor for X4 strains of HIV-1. The CC chemokines indicated in the figure are the natural binding molecules for CCR5. These CXC- and CC-chemokine molecules also have the ability to prevent virus entry via CXCR4 and CCR5, respectively. RANTES: Regulated upon Activation, Normal T-cell Expressed, and Secreted: MIP – macrophage inflammatory protein.
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n HIV-positive man with AIDS, known as the ‘Berlin Patient’ has become a global symbol of recent breakthroughs in potential HIV cures. In 2007, the Berlin Patient was given a bone marrow transplant in Berlin as a treatment for lymphoma (a cancer of the lymphatic system). In addition to having a tissue-typing match, the donor, by good fortune, had a deficiency in the CCR5 gene co-receptor that the HIV-1 virus uses to infect cells. Following the bone marrow transplant all signs of HIV-1 in the Berlin Patient completely disappeared. Four years later it is still undetectable. A very exciting time It’s a very exciting time as technology heads towards the manipulation of genes within cells to make them resistant to HIV infection. In the case of the Berlin Patient, the successful transplant led to the
disabling of the CCR5 co-receptor gene and resistance to HIV-1 infection by the patient’s new stem cell-derived CD4 cells. CD4 cells are a type of T-lymphocyte or white blood cell, and an important part of the immune system as they regulate the body’s response to infections. This ‘cure’ implied that approaches that successfully disable CCR5 should confer resistance to HIV-1 infection. Accordingly, technology is gearing up towards replicating this ‘cure’ in a laboratory setting where the patient’s own cells or a tissue donor’s cells can be manipulated to cause a co-receptor deficiency, or some other HIV antagonistic modification, before being transplanted. This gene-based therapy and other therapies discussed offer potentially world-changing cures for HIV-1 infection. Although HIV can be controlled using lifelong antiretroviral therapy,
Antiretroviral therapy HAART or highly active antiretroviral therapy is the therapy, composed of multiple antiHIV drugs, that is prescribed to many HIV-positive people. The therapy typically includes one nucleoside analog (DNA chain terminator), one protease inhibitor and either a second nucleoside analog (‘nuke’) or a non-nucleoside reverse transcription inhibitor (NNRTI).
ever closer to HIV cures Natural resistance to HIV infection The hallmark of HIV-1 infection and disease progression is the loss of CD4 T-cells over time, accompanied by increasing viral load. When untreated, the infection typically results in AIDS within 8 –10 years. Rapid progressors usually progress to AIDS within 2 - 3 years if untreated. Long-term non-progressors (5 - 15%) are HIV-1 infected individuals who have been infected for 10 years or more, but have good CD4 T-cell counts. Typically the counts remain constant and above 500 cells/µl in the absence of antiretroviral therapy. Some individuals have good control of their viral loads (number of HIV particles circulating in the blood) even when their CD4 counts are between 250 and 500 and may also fall into this category. Elite controllers are rare (1/300) and spontaneously suppress virus to undetectable levels (< 50 RNA copies/ml).
drug resistance and the adverse effects associated with antiretroviral drugs become a problem over the long term, as does the cost of the drugs. This has resulted in greater research efforts into identification of new viral or cellular targets for future HIV cures. The first is an eradicating cure, which involves the elimination of all virusinfected cells and the second is a functional cure, which results in the long-term suppression of the virus in the absence of HIV therapy (called ‘remission’).
Protective genetic or immune factors The ability of the host immune
Natural killer (NK) cells have the ability to be activated in the presence of tiny pieces of HIV-1 proteins (peptides) in a similar fashion to CD4 or CD8 T-cells. These responses are present in HIV-infected mothers who do not transmit virus to their babies, and in babies who do not become infected from their mothers, indicating that these NK responses may also play an important role in preventing HIV-1 infection. Image: Paul Weinberg
system to respond to HIV-1 is crucial to determining how resistant an individual is to acquiring infection in the first place, and how an individual might control the rate of their disease progression if already infected. Immune response capability is in turn influenced by genetic variation in immune response genes. There is little information on LTNPs
New body of research on HIVresistant individuals A new body of research on HIVresistant individuals within the genetically diverse sub-Saharan population hopes to go some way towards achieving these cures. Results from these studies may be used to provide the information required for new curative therapies that may involve gene or cell therapy. There is considerable variation in the degree to which different individuals are susceptible to HIV-1 infection. In addition, among those who become infected, their ability to control the course of the infection varies. Understanding what constitutes protection for disease progression in individuals with good control of their
disease holds the key to providing targets for novel interventions to control or even eradicate HIV-1 infection. One in 300 people infected with HIV is able to suppress HIV-1 replication and keep their viral loads at undetectable levels without receiving antiretroviral therapy. They are known as elite controllers (ECs), and they provide an ideal natural infection model for studying what constitutes a functional cure for HIV. Among people infected with HIV 5 – 15% remain healthy with high CD4 counts that may remain high for more than 10 years without antiretroviral therapy. These people are known as long-term non-progressors (LTNPs).
Innate and adaptive immunity Adaptive immunity develops after exposure to a foreign substance such as an infectious organism. Following repeated exposure to the same entity, immune responses are boosted (as occurs with vaccination). Cells of the adaptive response include T- and B-lymphocytes. Specific antibodies against the entity constitute the humoral or soluble component in serum. Adaptive immune responses are therefore highly specific and have a memory of earlier exposures to an organism. Innate immunity is fast acting, it is not dependent on memory of previous exposures and is not highly specific for the organism. However, recent findings have shown that natural killer (NK) cells do have properties of adaptive immune responses (specificity and memory). Other innate immune cells include dendritic cells, monocytes, macrophages and neutrophils. The soluble component in serum includes factors such as complement, acute phase proteins, cytokines, chemokines and antimicrobial proteins.
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Zinc finger nuclease action
What is a genome-wide association study? This is an approach that involves analysis of a person’s entire genetic makeup to detect markers of genetic variation, which are called single nucleotide polymorphisms (SNPs). For example, comparisons are made between individuals with a specific disease and those without. This enables correlation of specific variants with a disease state. This may provide important pointers for mechanisms that underlie the disorder. This technology has resulted in the discovery of many previously unknown markers of disease; however, minor variants that may not have a large effect are often missed. The DNA regions encompassing the HLA and KIR genes are the two most variable regions of the entire human genome. This is partly the result of selective pressures imposed by exposure to various pathogens during evolution. Differences in immune responses to different pathogens are likely to result from variation in these genes. An allele is a version of a gene that codes for a distinct trait that can be passed from parents to offspring – one version is inherited from each parent.
Zinc finger nuclease action. Zinc finger nucleases typically comprise two components (subunits) that recognise specific sequences of about 18 – 24 base pairs. Attached DNA-digesting components (nucleases) cut the two strands. When the doublestranded damage is repaired, a mutation is introduced at the site of action of the zinc finger nucleases to cause a disabling mutation.
Technology is heading towards the manipulation of genes within cells to make them resistant to HIV infection. Image: Philippa McKechnie
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and ECs who live in sub-Saharan Africa, the region most devastated by the HIV epidemic. In addition to this, African populations have substantial genetic diversity with differences in susceptibility and disease progression in the various populations. Intensive research involving these populations is essential. (This is a focus of Tiemessen’s work.) Natural killer cells Early in our studies we unexpectedly found that cells important in the innate immune response, called natural killer (NK) cells, have the ability to be activated in the presence of tiny pieces of HIV-1 proteins (peptides) in a similar fashion to CD4 or CD8 T-cells. These responses are present in all but one of the LTNPs and ECs we have studied to date, and are rarely detected in individuals who have low CD4 counts and high viral loads. We have also seen these responses in HIV-infected mothers who do not transmit the virus to their babies, and in babies who do not become infected from their mothers, indicating that these NK responses may also play an important role in preventing HIV-1 infection. As part of the approach to understanding the role of these interesting NK cells, Tiemessen’s research group has studied genes that code for KIR molecules (killer immunoglobulin-like receptors) that are expressed on the surface of NK cells. The group has investigated certain of the KIR binding partners such as HLA (human leukocyte antigens). The possession of particular versions of HLA genes (alleles) has been associated with protection from disease progression while the DNA region encompassing these genes on chromosome 6 has been found to have the most significant influence on disease progression in genome wide association studies (GWAS).
When compared with individuals who are HIV progressors, LTNPs and ECs have more protective versions of HLA genes. They also possess more HLA-C alleles that fall into the group-1 category (HLA-C1), which are characterised by HLA-C molecules binding particular KIR receptors on NK cells. In addition, these individuals have more gene variants of another group of receptors, called Fc receptors, which may influence how their NK cells recognise and ultimately kill infected cells. Here, antibodies would bind HIV-1 proteins on infected cells with one end and also bind the Fc receptor on NK cells on the other end, forming a bridge between the infected target cell and the killer cell. Furthermore they possess genetic variants of the CCR5 gene, which have been shown to be associated with slower disease progression, and they have an under-representation of variants associated with more rapid disease progression. Studies are ongoing that will comprehensively analyse the genetic or immunological factors associated with control of HIV-1 infection. Promising results Unravelling the role of the CCR5 co-receptor in HIV infection, following successes such as observed in the Berlin Patient, has had important implications for the development of novel viral treatments. Several studies are now in progress and the results are promising. Technology that entails the use of so-called Zinc finger nucleases is particularly exciting. These engineered enzymes are capable of cutting specific DNA sequences of the CCR5 gene to render it inactive. The methodology has advanced rapidly and preclinical studies show that the approach may be used to modify bone marrow stem cells. Early stage clinical trials using zinc
Q ASSAf News
Professor Patrick Arbuthnot and Professor Caroline Tiemessen. Image: Wits University
finger nucleases to disable CCR5 in CD4 cells have recently been completed and the approach is promising. Another group of powerful geneinactivating enzymes, derived from plant bacteria called transcription activator–like effecters (TALEs), are also being developed to make cells HIV-1 resistant. Other methods of disabling virus genes or HIV-1 host dependency factors are being employed. In an advanced clinical trial that is currently in progress at the City of Hope Hospital in California, Dr John Rossi and his colleagues have been able to use a three-pronged approach to make bone marrow stem cells of AIDS lymphoma patients resistant to HIV-1 infection. Molecular scissors that inactivate a virus gene (ribozymes), a gene silencing hairpin as well as a virus decoy were used. Preliminary results from the study are encouraging. Research aimed at developing treatment that is based on insights derived from understanding the link between HIV-1 disease progression and genetic characteristics of individuals will no doubt result either in cures or in far more effective management of HIV-1-infected individuals in the future. ‘It’s a very exciting time” ❑ Professor Caroline Tiemessen is from the Centre for HIV and STIs, National Institute for Communicable Diseases, National Health Laboratory Service and Faculty of Health Sciences, University of the Witwatersrand. Professor Patrick Arbuthnot is the Director of the Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand.
South African Young Academy of Science (SAYAS) launched The Deputy Minister of Science and Technology, Mr Derek Hanekom, launched the South African Young Academy of Science (SAYAS) on 27 September 2011. In his address, he said that a progressive and dynamic forum will propel South Africa’s young scientists to fully participate in local and internationally relevant research and development agendas. This milestone event in the South African science and higher education sectors follows the facilitation of the establishment of a young academy by the Academy of Science of South Africa (ASSAf). SAYAS provides a national platform where leading young scholars from all disciplines in the country can interact, and also access international networking and career development opportunities. In South Africa, a Young Academy will contribute primarily to the achievement of the national strategic priority of strengthening the skills and human resource base of the country. Its particular niche will be to focus on strengthening high-level skills amongst young scientists and the promotion of excellence. Young scientists represent the future of a country’s science and technology development and their inclusion from an early stage in the processes that build a country’s system of innovation is critical. Over the last few years, several international initiatives have been implemented to motivate active research by young scientists in recognition of the crucial role they play in the future of a nation. One such initiative was the creation of the Global
Young Academy (GYA) in 2010, which seeks to provide a voice to young scientists on international issues that interface with science. Stemming from this initiative, global young scientists have also envisioned the creation of national young academies, which seek to galvanise young scientists to address issues of national importance. As in other countries, young scientists in South Africa are drawn from a broad background in recognition that the solution of local and global challenges requires deep understanding across disciplines and cultures. Young scholars from the full spectrum of disciplinary enquiry will be embraced by SAYAS. The goals of SAYAS include contribution to the career development of young and emerging scientists; provision of mentoring and role modelling services to learners and the youth; promotion of science awareness among learners, youth and society in general; fostering of links between South African young scientists and those in the rest of Africa and globally; and fostering of links between young scientists and the business community. SAYAS also aims to provide evidence-based policy advice to government and society on issues affecting young scientists. SAYAS will collaborate with the established Academy of Science of South Africa on projects and activities related to young scientists’ development. A group of 20 Founding Members of the Young Academy was inaugurated by the Deputy Minister of Science and Technology during the launch.
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The mathematics behind the Traditionally in mathematics we are taught that: negative x negative = positive and negative x positive = negative. But in HIV we encounter a new reality: negative x negative = negative and negative x positive = positive. Quest’s resident mathematician, Steve Sherman, explains the maths of HIV transmission.
IV/AIDS is one of the most significant afflictions of the past 20 years. It has affected the human race in ways that are difficult to both quantify and qualify. Apart from the obvious reduction of the population (the number of deaths have been larger than the number of births, thus resulting in a decline in the population figures), the detrimental impact of HIV has had far-reaching consequences that I feel warrant a mention. The virus has changed the way people socialise (dating and sexual behaviour), the way businesses run (HIV policy, huge staff losses due to ill employees and the resulting drop in productivity), changes to family structure (children are now heading households where both parents are ill or have died), the finance markets are affected (health insurance and dread disease cover), economics (hospitals and antiretroviral drugs need to be made available to large numbers of people that are not in a position to afford medication or treatment, communities are imploding from within) and this is just the tip of the iceberg. Knowing how serious HIV is, how widespread it is and how it can destroy families and communities, you would think that people would take the warnings about protecting themselves and their loved ones with more enthusiasm. A significant concern with HIV/AIDS is that there
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are so many people that feel it is a problem that affects ‘other people’ and not themselves. You often hear remarks such as, ‘... it is a poor person’s disease’ or ‘a gay person’s disease’ or an ‘immoral person’s disease’. I am ashamed to point out that we went through a period of our history where the government adopted a very puzzling position on the treatment of HIV. From the late 1990s the then president, Thabo Mbeki, turned his back on the scientific consensus that AIDS was caused by a viral infection that could be fought – though not cured – by sophisticated and expensive medical drugs. AIDS, he said, was brought about by the collapse of the immune system – but this was not caused by a virus. The cause, he said, was poverty, bad nourishment and general ill-health. The solution was not expensive Western medicine, but the alleviation of poverty in Africa. According to one paper, the government’s choice of action resulted in the deaths of about 300 000 people. Fortunately the driving force of civil society made up of the medical fraternity, NGOs and other communitybased organisations, played a large role in convincing the new government to do an about turn and tackle the virus head on. Antiretrovirals are now much cheaper, and in many cases have been donated to South Africa, and this has led to the improvement in quality of
life for many people that have been afflicted with the virus. However, we are still dealing with the impact that the government of the 1990s set in motion. Mathematics and HIV I alluded earlier to the notion that empowering people with information about HIV has been problematic, partly because of cultural beliefs, teenage invincibility, insufficient teaching time, educators with limited content knowledge about HIV, and an ineffective media campaign that targeted teens and finally a poor role model for a president who had the audacity to claim that he reduced his risk of being infected with HIV by taking a shower after engaging in unprotected sex with a woman who he knew had the HI virus. So how can we use maths to get the idea across to young people that HIV is a danger to them? I was asked to give a presentation on HIV/AIDS to a group of 200 teenagers. I knew that it was a weeklong HIV/AIDS programme so by the time I had arrived, they had already experienced the ABC talk (abstinence, be faithful and condomise). I cannot say that these three actions will not be effective ways of reducing the transmission of the virus. However, I will suggest that if you take the ‘home run’ out of the equation and feel that abstinence from sex is a good solid step, you are naïve and run the risk of
transmission of HIV overlooking the fact that teens engage in other ‘bases’ that can still play a significant role in spreading the virus (e.g. anal sex). So how did I get this across to the 200 teens? All the teens gathered in the school hall and each was handed a plastic cup filled halfway with a clear liquid. The teens were instructed to use the 15 minutes that they were going to receive, to ‘meet’ as many other students as possible. A ‘meeting’ meant pouring half of your water into another person’s cup and they would then pour the water back into yours. They would then introduce themselves to each other and move onto the next ‘meeting’. After 15 minutes was up, they were told to return to their seats. On the table in front of each teen there was a small strip of blue litmus paper. They were asked to dip the strip into their cup and raise their hand if there was any discolouration with a hint of red. After five minutes of banter, they ALL raised their hands. That was when I broke the news that we had actually filled five out of the 200 cups with white vinegar instead of water! The blue litmus paper would show varying shades of red depending on how diluted the vinegar was in each person’s glass. The giggling was reduced to murmurs and whispering. I then explained to them that in the ‘real’ world, if there were five people who were unaware that they had HIV and they hooked up with 200 people over 15 periods of time, the heart-stopping conclusion is that 200 people could potentially become infected. If you take 200 people who are unaware of their HIV status and they connect with many
more people in 15 periods of time, the numbers would be horrific. The teens were unusually silent. This mathematical modelling exercise was a real eye-opener for all of them. The idea of abstinence became very real. The promotion of condomising became apparent without any protests. The utopian approach to being faithful and monogamous now made sense. I spoke with many of these students after the exercise and there was consensus that this was the first time the HIV message had actually sunk in. The maths of prevention and treatment Mathematics forms a very large part of the decision-making around the prevention and treatment of HIV. Mathematical modelling of the behaviour of cells being subjected to various treatments will allow scientists to determine the behaviour of those cells after dosing with various medications. Sometimes using mathematics can also involve thinking outside the box: antiretroviral drugs are currently far more expensive than condoms and male circumcision – the pillars of current prevention. In today’s financially constrained world can First World countries (with low HIV infection rates) afford to give drugs to healthy people just in case they may, possibly, be at risk of HIV? Please understand that antiretrovirals are critical in the South African context – they have been very positive in the fight against HIV. HIV is infectious, but when we compare different political approaches it is important to consider how, by
avoiding an infection, additional chains of future infections may also be prevented. Advanced forms of calculus (not unlike anything you did at school) are used to predict how HIV may spread in different countries. Mathematical models can use data on how much sex everyone is having – and with who – to predict where HIV may spread next. These models are generally used as ‘what if’ scenarios – these allow us to make projections and predictions. We need more mathematicians to help us tackle HIV. We need you! ❑ Steve Sherman was voted the fifth bestlooking mathematician in the world by his mother. He can read upside down and knows the first four digits of PI.
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Tool use by early modern humans In another coup for local archaeologists, a 100 000-year-old toolkit and ochre workshop have been discovered at Blombos Cave. By Shirona Patel.
n ochre-rich mixture, possibly used for decoration, painting or skin protection 100 000 years ago, and stored in two abalone shells, was discovered at Blombos Cave, an archaeological site situated in a calcarenite limestone cliff on the southern Cape coast, near Still Bay, 300 km east of Cape Town, South Africa. The research pertaining to this discovery was published in the prestigious international journal Science, on Friday 14 October 2011.
The cave at Blombos on the southern Cape coast.
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Image: Chris Henshilwood
The MSA levels at Blombos Cave Blombos Cave is 35 m above sea level and located about 50 m from the coast. The Middle Stone Age (MSA) levels at Blombos Cave are divided into three phases: M1, M2 (upper and lower), and M3. The M1 and upper M2 phases (78 000 - 72 000 years) contain Still Bay-type bifacial foliate points, engraved ochre and bone, bone tools, and Nassarius kraussianus shell beads. The lower M2 phase dating to about 85 000 years ago contains low-density deposits, suggesting that the cave was seldom used at this time. The M3
Blombos Cave from the coast.
Image: Magnus Haaland
phase contains dense shellfish deposits, in situ hearths, faunal remains, stone tools, and many pieces of modified ochre. Ochre is a colloquial term used by archaeologists to describe an earth or rock containing red or yellow oxides or hydroxides of iron.
‘The ochre processing toolkits were recovered in the lower M3 phase. They were found within layer CP (dated to 100 000 years) composed mainly of aeolian dune sand, and lay on a thin orange sand layer, CPA. Within layer CP there are few artifacts apart from the toolkits,’ says Professor Christopher Henshilwood from the Institute for Human Evolution at the University of the Witwatersrand, Johannesburg and University of Bergen, Norway, who together with his international team, discovered a processing workshop in 2008 where a liquefied ochre-rich mixture was produced. ‘Ochre may have been applied with symbolic intent as decoration on bodies and clothing during the Middle Stone Age.’
The south section of Blombos Cave, showing the layers, phases and ages. Image: Wits University
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Left: The nacre and inside of the TK1 abalone shell (TK1-S1) after removal of the quartzite grindstone. The red deposit is the ochre rich mixture that was in the shell and preserved under the cobble grinder. Image: Grethe Moell Pedersen Left (below): Karen van Niekerk removing the TK1 abalone containing the ochre grinder and ochre from the deposit in the 100 000-year-old layers at Blombos Cave. Image: Grethe Moell Pedersen
The toolkits The two toolkits, which were of the same date and which were found close together, were discovered in situ during excavations in 2008. The toolkits included ochre, bone, charcoal, grindstones and hammerstones. Henshilwood describes the content of the toolkits: ‘Toolkit 1 comprises a stack of artifacts above and below a Haliotis midae (abalone) shell. A quartzite cobble, tightly fitted within the shell aperture, has use-wear marks consistent with its application as a percussor and grinder.’ ‘The upper face is stained with red ochre and encrusted with fragments of spongy bone. Removal of the cobble revealed a 5 mm-thick red compound adhering to the shell nacre (an inner layer of mother of pearllike composite material) overlain by a khaki-coloured aeolian sand,’ explains Henshilwood. ‘Microscopic
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and chemical analysis of the red compound in the abalone shell shows the presence of crushed trabecular (spongy) bone, once rich in fat and marrow, that may have acted as a binder in the compound; charcoal fragments; quartz and quartzite microflakes with ochre on some of the striking platforms and quartz grains coated with ochre powder and other substances’. Only minute quantities of ochre occurred in the CP layer in which the toolkits were discovered. The khaki-coloured sand overlying the red compound in the Toolkit 1 abalone consists of quartz grains, minerals and the remains of vertebrate microfauna, marine snails and slugs, seed shrimps, foraminifera, urchin spines, lamellibranches, and calcitic worm tubes. Lying below the abalone were the distal portion of a canid (dog) ulna with ochre residues on the broken tip, a seal scapula with
Blombos Cave interior panorama view.
numerous microspots of red ochre on its lateral surface, a broken bovid vertebra and a quartz flake with red ochre residues and a microchipped edge indicating its use as a grinder and two quartzite flakes. Similarly, Toolkit 2, discovered about 16 cm from Toolkit 1, comprises an abalone shell with a red compound on the nacre of the inner surface. The nacre shows traces of ancient linear marks that were produced when quartz grains were gently moved across the surface during mixing. A small quartzite core rested close to the anterior edge of the Toolkit 2 abalone, and was used for grinding and the production of ochre powder. ‘It is likely that the ochre was sourced from at least several kilometers away, and the rest of the objects that make up the toolkits were available in the immediate environment,’ adds Henshilwood.
Christopher Henshilwood, lead author, excavating the 100 000-year-old levels at Blombos Cave. Image: Wits University
The workshop According to Henshilwood, the close proximity of the two toolkits suggests that they were used at the same time. ‘Because both toolkits were left in situ, and because there are few other archaeological remains in the layer of sand in which they were found, it seems that the site was used primarily as a workshop and was abandoned shortly after the compounds were made. Aeolian sand then blew into the
The manufacturing process Grinding or scraping ochre to produce a powder for use as a pigment was common practice in Africa and the Near East more than 100 000 years ago. However, archaeological
evidence for the procedures that MSA people followed during the handling, preparation, storage and application of ochre is limited. ‘We believe that the manufacturing process involved the rubbing of pieces of ochre on quartzite slabs to produce a fine red powder, and some were knapped with large lithic flakes, forming ochre chips. These ochre chips were crushed with quartz, quartzite and silcrete hammerstones/ grinders. It is likely that a mediumsized mammal bone was heated to extract the marrow fat and then crushed with a stone hammer. The hematite powder and the heated, crushed bone were combined with charcoal, the stone chips and a liquid. These substances were introduced to the abalone shells and gently finger stirred. A canid bone was probably used to transfer some of the mixture out of the shell,’ says Henshilwood. Charcoal is rare in the layer where the toolkits were found, suggesting that it was a deliberate addition to the mix. The quartz and quartzite chips, produced during the action of crushing the ochre, and the quartz grains may have been incidentally incorporated.
Image: Magnus Haaland
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Above: Components of the TK1 toolkit including the abalone shell, grinders, ochre, bone tool, seal scapula and bone. These items were stacked upon one another and when recovered were probably almost in the same position as when they were left there 100 000 years ago. Image: Wits University Left: Karen van Niekerk and Grethe Moell Pedersen pointing to the 100 000-year-old TK2-S1 abalone shell with ochre before recovery in 2008. Image: Christopher Henshilwood
cave from the outside, encapsulating the toolkits.’ There is evidence that at least some of the components of the toolkit were re-used, suggesting that production was not a one-time event. ‘For example, we can determine that one of the grinders was used to grind yellow goethite and then re-used to grind red ochre.’ Complex human cognition ‘We are not sure of the exact use
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of the ochre compound,’ says Henshilwood. ‘We did not detect any resin or wax that might indicate that it was an adhesive for hafting. However, we believe that it could possibly have been used to paint a surface in order to decorate or protect it, or to create a design.’ He elaborates on the importance of the find: ‘This discovery represents an important benchmark in the evolution of complex human cognition in that it
Challenging perceptions Professor Christopher Henshilwood challenges perceptions about the origin of modern human behaviour and Africa. As a child he loved exploring the caves on his grandfather’s farm in Blombos, blissfully unaware that one of the greatest finds in archaeological history was lurking in the dark interior of his playground. Nearly forty years passed before Christopher Henshilwood, a research professor at the Institute for Human Evolution at the University of the Witwatersrand, Johannesburg and the University of Bergen, Norway, realised that the cave was an archaeological site. In 1999 and 2000 – almost ten years after his initial exploration – he discovered two engraved ochre slabs that challenged existing beliefs about the origin of modern human behaviour. Up until his discovery it was generally accepted that the origin of modern human behaviour could be traced to Europe dating back approximately 35 000 years. Henshilwood’s discovery proved beyond doubt that modern human behaviour has its roots in Africa at least 100 000 years ago. Henshilwood returned to South Africa in 2007 after being awarded a South African Research Chair in the Origins of Modern Human Behaviour by the National Research Foundation and also retains a professorship in Bergen, Norway.
Research focus His research is focused on determining when people started behaving in a way that we would identify with today. ‘Archaeologists cannot “see” language, but they can study behaviour and the use of symbols to convey a meaning that is unique to humankind,’ says Henshilwood. ‘All we can do is”read” the very few symbolic artefacts that date back to beyond 60 000 years ago. Although we look for symbols in the archaeological record, a symbol is exactly that – a symbol – it represents or stands for something else.’ According to Henshilwood, it is extremely difficult to determine whether or not a symbol has a specific meaning. Symbols dating back 10 000 or 100 000 years ago, do not necessarily have the same meaning that they convey today. Archaeologists compare the ancient and modern meaning of symbols in an attempt to discover the meaning of a symbol. ‘Information from the recent past is not going to tell you about events dating back 100 000 years, but it can give you a hint,’ adds Henshilwood.
next step was to determine what these abstract patterns meant and why they were made. ‘The point about any symbol is to convey a meaning to someone else within your group or another group – otherwise there is no point,’ says Henshilwood. His second major discovery came when the team discovered tiny estuarine shell beads which displayed clear signs of wear as a result of being strung. The beads were discovered in the 75 000-year-old levels at Blombos Cave and served as a proxy for the first discovery. Research revealed that the beads were worn as jewellery. Jewellery and art are symbols that stand for something else – they convey a specific message or tell you something about the person wearing it. The message that is conveyed will only be understood by a person who knows what the symbol means, according to Henshilwood. ‘Some symbols could be universal, but most symbols do not serve universally. Meaning has to be passed on from individuals or groups of people.’ The discovery of the ochre and the beads provided further evidence that the inhabitants used symbols to convey a specific message at least 75 000 years ago. Further digging in the 100 000-year levels revealed similar engraved pieces. ‘This means that it is not likely that the patterns made on the ochre were done by one person in the cave once and never again – this was in fact an ongoing tradition’ deduces Henshilwood.
International collaboration Henshilwood, who supervises several graduate and postgraduate students, and his team continue to work at the Blombos site and have also started excavating at an additional MSA site, Klipdrift Shelter, discovered in the De Hoop Nature Reserve on the southern Cape Coast. He has also established strong relationships between Wits, the University of Bergen in Norway and the University of Bordeaux in France. ‘The advantage of these collaborations is that young South African scientists will benefit greatly from the skills that will be brought from Europe and it will also permit them to work in some of the best laboratories in the world. Similarly, our South African team have much to share with researchers from other continents.’
First great discoveries
Henshilwood made his first great discoveries in 1999 and 2000 while excavating in the 75 000 year levels in Blombos Cave. He found two pieces of ochre – a soft, red rock still widely used by aboriginal people around the world today – and noticed abstract engravings on both pieces. Subsequent to these first finds, the team found 14 similar pieces with a variety of engraved patterns at the Blombos site, some 100 000 years old. ‘After studying the ochre pieces, we realised that the engravings were a deliberate act of placing a design on a surface,’ recalls Henshilwood. The discovery of the engraved ochre led to a debate as to whether or not an abstract symbol is in fact a symbol, whether or not it has meaning, and whether it is arbitrary or random. The research findings indicate that the patterns were not random, but were in fact carefully executed. The
Apart from the excavations and the analysis of artefacts at De Hoop, the team – comprising archaeologists, palaeoclimatologists and students from Wits, Bergen and Bordeaux – will also focus on climate reconstruction dating back from 25 000 to 160 000 years. According to Henshilwood this reconstruction is extremely important because people’s behaviour is influenced by climate. ‘Groups are unlikely to venture into new areas where the climate is unsuitable and where it is difficult to find food. This means that during adverse climatic conditions population sizes may shrink very rapidly or move away from an area. One result of diminishing population size may be a reduction in innovation.’ There is definitely more to be unearthed by Henshilwood and his team, as clues from the past help us to plan for the future.
shows that humans had the conceptual ability to source, combine and store substances that were then possibly used to enhance their social practices.’ Dating The quartz sediments in which the ochre containers were buried were dated to about 100 000 years using single-grain optically stimulated luminescence (OSL) dating. This age is consistent with those determined through the thermoluminescence dating of burnt lithics and the dating of calcium carbonate concretions using uranium-series dating methods. Optical dating techniques determine how long ago mineral deposits were exposed to daylight.
Implications ‘The recovery of these toolkits adds evidence for early technological and behavioural developments associated with humans and documents their deliberate planning, production and curation of pigmented compound and the use of containers. It also demonstrates that humans had an elementary knowledge of chemistry and the ability to make long-term plans 100 000 years ago,’ concludes Henshilwood. The find has attracted international attention and has featured in the media in 66 countries around the globe. ❑ Shirona Patel is the communications manager at Wits University. She writes on behalf of Professor Christopher Henshilwood and his colleagues.
Members of the excavation team at Blombos Cave when the toolkits were discovered in 2008. From left: Rune Fredriksen, Grethe Moell Pedersen, Stein-Erik Lauritzen, Turid Hillestad-Nel, Karen van Niekerk, Christopher Henshilwood. Image: Birgit Stav
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The Namibian Kalahari.
A satellite photograph of the Kalahari region.
Image: Wikimedia commons
An ice core showing clear annual layers.
Image: Wikimedia commons
What happens to man-made CO 2 emissions? Carbon dioxide is the most important of the greenhouse gases man produces – but have you ever wondered what happens to it all? By Mike Lucas The National Climate Change Response White Paper and COP-17 In a national effort to reduce the impacts of greenhouse gases and to slow down the rate of global warming, the South African Government (Department of Environment Affairs) has very recently (in September) produced a so-called National Climate Change Response White Paper (on Google) that sets out future targets for reducing greenhouse gas emissions. This is an important document that will also form part of exceptionally important and crucial international discussions and negotiations about to take place in Durban, from 28 November – 9 December this year. This is the 17th Conference of the Parties (COP-17) to the United Nations Framework Convention on Climate Change (UNFCCC). At the same time, the 7th Session of the Conference of the Parties serving as the meeting of the parties (CMP-7) to the Kyoto Protocol will also meet in Durban. The overall goal of COP-17 will be to draw up and adopt binding decisions about global greenhouse gas emissions – and to set out practical and effective implementation guidelines to ensure that COP decisions are achievable. Previous meetings, such as that in Copenhagen (Denmark) have failed to come up with unanimous agreements – with some nations withholding their support. COP-17 in Durban is therefore seen as a crucial test of international political willpower to adopt meaningful restrictions and controls on greenhouse gas emissions.
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cientists are now almost 100% certain that greenhouse gases such as CO2 produced from burning coal, oil and natural gas are causing global warming. Heavy industry, mining and cars are the major culprits in South Africa – but how hot might it get? The best and most reliable projection of future warming in southern Africa is about plus 3–5 °C within the 21st century, perhaps more. Greatest warming will be on the western side of South Africa, from about the northern Cape to southern Angola, particularly in the Kalahari region. Here, temperatures could rise by 5–6 °C. Coastal areas will eventually warm by a similar amount (3–5 °C), but warming will be delayed because of the cooling effect of adjacent oceans. Such warming will have major impacts on ecosystems, on agriculture, on rainfall distribution and intensity, as well as on South Africa’s ability to maintain its supply of drinkable water. Vitally important though these issues are, this article instead
considers the question of where all the CO2 emissions go. This is important, because Earth’s ecosystems play a major role in regulating how much CO2 actually lands up in the atmosphere. Understanding how Earth’s ecosystems mop up unwanted CO2 (and other greenhouse gases) allows scientists to make predictions about how hot it will get – and when. Recording emissions Humans are currently emitting about 9 Gt C y-1 (= 9 billion tons per year) of CO2 into the atmosphere from fossil fuel burning (7.5 Gt C y-1) and from land-use changes (1.5 Gt C y-1) mostly in the northern hemisphere. As a result, atmospheric concentrations in 2011 (~390 ppmv) are very much higher than they have been for the last 600 000 years, which we know from palaeoclimate records of CO2 trapped in Antarctic and Greenland ice-cores. These ice-caps of up to 4 km thick have trapped atmospheric gases within tiny bubbles in the ice layers as the ice-caps formed. These contain the
NO 2 (ppb)
700 500 Present Day 600
400 300 200 Thousands of years before 2009
CO 2 (ppm)
600 000 YEAR ICE-CORE RECORD OF GREENHOUSE GASES
Q Climate science
A 600 000 year record of atmospheric carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) greenhouse gases recovered from bubbles of gas trapped in Antarctic icecores. CO2 concentration is expressed as parts per million (ppm), while that for CH4 and N2O is expressed as parts per billion (ppb). The ‘starred’ values on the right-hand Y-axis are present-day concentrations. ATMOSPHERIC CO2 AND O2 MEASUREMENTS 400
380 370 360
Fossil Fuel CO2 Emissions 1990 -1999 +1.3% per year 2000 -2006 +3.3% per year
-60 Falling O 2 Consumption is due to burning fossil fuel & wood
-70 -80 -90
Mauna Loa CO2
1978 South Pole CO2
1994 Mauna Loa O2
Relative O2 Concentration (ppm)
CO 2 concentration (ppm)
South Pole O2
A record of atmospheric CO2 and relative O2 concentrations taken from Mauna Loa, an island in the Pacific Ocean, and from the South Pole.
winter respiration by plants in the northern hemisphere, which respectively causes a seasonal cycle of decreasing and increasing atmospheric CO2 concentrations. Other CO2 observatories have since been established around the world, including one at Cape Point, South Africa (1992), which all show exactly similar increases in CO2, although the seasonal amplitude in the southern hemisphere is much less because of oceanic rather than terrestrial influences. The declining O2 concentration is due to the fact that O2 is required for the combustion of fossil fuels and wood. Natural CO2 emissions from volcanism, for example, are not associated with a decline in O2, so falling O2 concentrations prove that CO2 increases come from combustion processes that use oxygen.
Image: Wikimedia commons
The fate of emissions Unless there is a reduction in CO2 emissions, this upward trend will continue, and ecosystems will face CO2 concentrations that were last seen more than 650 000 years ago, while average global temperatures will become the highest experienced in the past 740 000 years. Currently, about 46% of CO2 emissions accumulate in the atmosphere, while the world’s oceans take up about 26% of the total, and land masses remove the remaining 29%. Land masses and oceans are therefore natural ‘sinks’ for CO2 that partly offset man-made CO2 emissions. In fact, if the land and the oceans did not naturally take up this CO2, more would accumulate in the atmosphere and global warming would be far more severe than it is. A schematic summary of Earth’s current terrestrial and oceanic CO2 exchanges with the atmosphere is shown as a global carbon budget which was constructed by the climate scientist Christopher Sabine and his colleagues in 2005. Terrestrial plants remove atmospheric CO2 by photosynthesis, which fixes CO2 into organic carbon that is stored in the plants, for example as the woody material in trees and shrubs, or as cellulose in grasses. Plant photosynthesis is therefore a ‘sink’ for CO2. However, since plants also respire and release CO2 back into the atmosphere, this is a ‘source’ of CO2. Other sources of CO2 come from the bacterial decomposition of dead organic matter in soils. Similarly, agricultural activities such as ploughing and poor land management practices provide other CO2 sources. And as the northern hemisphere is dominated by land rather than by oceans, it is that hemisphere that dominates terrestrial CO2 sources and sinks. On a regional scale, tropical and northern hemisphere temperate forests are net annual sinks for CO2, while western Europe is a net CO2 ▲ ▲
clues to Earth’s ancient climate. By drilling deep down – as much as 1 - 2 km into the layers of ice – scientists have been able to measure the gas composition of Earth’s ancient atmosphere in these tiny bubbles, and compared this with Earth’s past climate to show how climate and atmospheric gas composition are interlinked. The best modern record of atmospheric CO2 comes from an observatory first established on the Pacific island of Mauna Loa by Charles Keeling in 1958, that was continued by his son, Ralph Keeling. Their famous observations show the continuing upward trend in CO2 concentrations coupled with a decline in atmospheric O2 concentrations. Embedded in their data is a strong seasonal signal associated with summer photosynthesis and
The observatory at Mauna Loa, Hawaii.
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FATE OF MAN-MADE CO2 EMISSIONS (2000-2007) De-forestation & burning, 1.5 Gt C per year
13 million hectares each year
4.2 Gt C per year (46%)
Land 2.6 Gt C per year (29%)
Carbon Emissions = 9 Gt C per year
Carbon Emissions (Gt C per year)
2.3 Gt C per year (26%)
Fossil fuel burning, 7.5 Gt C per year
A summary of where man-made CO2 emissions went between 2000 and 2007. The values are in Gigatonnes of carbon per year (Gt C y-1). One Gt = a billion tonnes of pure carbon. To convert this to CO2, multiply the values by 3.667.
GLOBAL CARBON BUDGET (2000-2005) (Gt C per year) re-drawn from Sabine, 2005
Fossil fuel & cement emissions
Atmosphere 794 Respiration & fires
rivers Plants & Soil 6,850
1 river fluxes 1.1
0.4 Fossil Organic Carbon >6,000
Units are Gt C for reservoirs and Gt C per year for fluxes
The average combined natural and man-made global carbon cycle for the period 2000 to 2005. Arrows represent exchanges in Gt C per year, while circled values are carbon stores, in Gt C. The red arrows represent man-made emissions.
source because it is heavily populated and industrialised, where fossil fuel emissions exceed CO2 fixation by plants. Nevertheless, the net annually and globally averaged balance of combined terrestrial sinks (59.6 Gt C y-1) and sources (58.0 Gt C y-1) from 2000 to 2005 was a slight overall sink of 1.6 Gt C y-1. This means that the land is still sucking up more CO2 than it is releasing to the atmosphere – but this could change in the future.
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Carbon dioxide in the oceans A similar inventory and budget can be done for the oceans. Ocean processes that remove atmospheric CO2 consist of the ‘biological carbon pump’ and the ‘physical solubility pump’. The biological carbon pump is driven initially by phytoplankton photosynthesis, which fixes inorganic CO2 into particulate organic carbon (POC), exactly as terrestrial plants do. When phytoplankton cells ultimately die
and sink, their cells of POC sink into the deep ocean, thereby effectively removing CO2 and its warming influence from the atmosphere. However, phytoplankton distribution and growth in the oceans is not uniform, but is predominantly confined to productive coastal and temperate regions of the world oceans, so it is in these regions that the biological removal of atmospheric CO2 is at its strongest. Alternatively, and as the name implies, the ‘physical solubility pump’ depends on the solubility of gases in water to remove atmospheric CO2. The solubility of gases increases with decreasing water temperature, while gases become less soluble as water warms. Thus cold oceans take up more CO2 by this process than do warm oceans, and indeed, where oceans are warm enough, CO2 may be ‘out-gassed’ back into the atmosphere. Overall, cold polar oceans are therefore generally a ‘sink’ for CO2, while warm sub-tropical and tropical oceans are often a ‘source’ of CO2 back into the atmosphere. The global oceans therefore consist of a mosaic of sources (90.6 Gt C y-1) and sinks (92.2 Gt C y-1) for CO2, but with a net annually and globally averaged small sink of (1.6 Gt C y-1). If you add river inputs of 1.1 Gt C y-1, the oceanic sink becomes 2.7 Gt C y-1. The combined terrestrial and oceanic sink is therefore 4.3 Gt C y-1, set against total anthropogenic CO2 emissions of ~9 Gt C y-1. This means that only 4.7 Gt C y-1 accumulates in the atmosphere at the moment. Of course the major question is how will the small terrestrial and oceanic sinks for CO2 respond in the future? Will they continue to mop up ever more CO2, or will these sinks weaken or even become net sources of CO2, leading to an even faster acceleration of atmospheric CO2 concentrations? The simple answer to this is that although we don’t know for sure, it is likely that the capacity of the land and the oceans to keep on mopping up CO2 will become less. This is precisely the reason why greenhouse gas emissions must be dramatically reduced – and also why the outcome of COP-17 is so important for Earth’s future. ❑ Associate Professor Mike Lucas is employed within the University of Cape Town’s Zoology Department. He is also an Honorary Research Associate at the National Oceanography Centre (NOC) in Southampton, UK. He conducts much of his research in the North and South Atlantic, as well as in the Southern Ocean and in the Benguela upwelling system. He is a member of the southern African SOLAS Network, which forms part of the International SOLAS Project.
Careers in the forestry and forest products sector By Brand Wessels
ost of us know that furniture, paper and board products are often made from wood. But did you know that products such as ice cream, rocket fuel, baby food, some clothing items, chewing gum and paint also contain elements from wood? It is therefore not surprising that the forest and forest products sector has many interesting employment opportunities ranging from forest scientists and conservationists working in the areas where trees are grown, to wood products scientists and engineers managing production of end products from these trees. There are also accountants, human resource managers, IT specialists and many other professions active in the forest and forest products sector. In 2009 the South African forest and forest products industry employed about 120 000 people and produced products worth roughly R20 billion (Godsmark 2010). Although there are many professions active in such a large industry, two career paths specialise exclusively in the forestry and forest products sector. Foresters and forest scientists focus on growing, managing, conserving and improving the tree and land resources that are required for either industrial forestry use or for conservation. Wood products scientists and wood technologists focus on the products and optimisation of manufacturing processes where wood or wood fibres are used. A forester or forest scientist can specialise in one of many fields. Some forest scientists specialise in tree breeding, which requires a strong genetics background. Others become plantation managers where an afforested land area is managed for a specific purpose such as producing fibre for pulp production or trees for sawlog production. Forest scientists who focus on the harvesting, land preparation and logistics involved in a commercial forestry operation are called forest engineers. Many forest scientists choose to specialise in very specific fields like forest ecology, conservation or planning.
If any of these careers interest you the best option will be to enroll for a degree in forest science or a diploma in forestry. Stellenbosch University is the only university in South Africa that presents a four-year bachelor of science degree in forest science. You need the following Grade 12 results to enroll for this degree: n Afrikaans or English (Home Language or First Additional Language) 4 n Mathematics 4 n Physical Sciences 4 OR n Physical Sciences 3 and Life Sciences 4. The Saasveld campus of the Nelson Mandela Metropolitan University also presents a forestry diploma and a B-Tech degree in forestry. A wood products scientist is primarily concerned with the development and manufacturing of products from trees and wood. Wood products scientists need to be good problem solvers and are often employed by forest products processing companies to optimise their production processes or to develop new or improved products. Wood products scientists have a strong link with engineering, particularly industrial engineering. At Stellenbosch University, the only university in South Africa that offers a degree in wood
products science, about 60% of the curriculum is from the engineering faculty. You need the following Grade 12 results to enroll for this degree: n Afrikaans or English (Home Language or First Additional Language) 4 n Mathematics 5 n Physical Sciences 5. The Saasveld campus of the Nelson Mandela Metropolitan University also presents a diploma in wood technology and a B-Tech degree in wood technology. Suggested reading Godsmark, RC. 2010. The SA Forestry and Forest Products Industry 2009. http://www.forestry.co.za [accessed 26 October 2011].
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Figure 3: An aerial view of Tierberg Nature Reserve near Prince Albert in the Karoo, where riparian zones characteristically snake through the landscape. Image: CJ Crous
Casparus J Crous, Shayne M Jacobs, and Karen J Esler explain the importance of rivers in the South African ecosystem.
Conserving our rivers: a meander some way, either for recreation, food production, or indirectly as a source of clean water. Since riparian soils are usually rich in resources such as nutrients, they are often degraded as a result of human activities such as clearing for agriculture, grazing, and are also frequently invaded by alien trees, grasses and herbs. However, these areas benefit humanity in preventing pollution of rivers, mitigating floods, providing habitats for plant and animal species and providing recreational space for people.
Figure 1: The Palmiet River is an example of a typical fynbos riparian zone, taken at Kogelberg Nature Reserve, Western Cape. Image: M. Naude
What is a riparian zone? Most South Africans live close to a river and riparian zones can be found along most of these rivers. In fact, they straddle the boundary (or ecotone) between terrestrial and aquatic ecosystems, occupying river banks, and the banks of wetlands and estuaries. The areas that surround waterbodies are composed of soils that range from
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moist to water-saturated. They contain water-loving plant species and their associated ecosystems, which are important transition areas that connect the water with the land, and host a wide array of plant and animal life. The word riparian is from the Greek word for river, ‘ripa’, and literally means ‘belonging to the river’ (Figures 1 and 2). Most of us use riparian zones in
The ecology of riparian zones Ecology is the study of the interaction between all living and non-living elements in nature. In riparian zones this means the interaction between plants, animals, microorganisms, soil and water, particulalry because these zones are next to waterbodies. Because riparian zones are usually at the bottom of valleys, this means that water, sediment and dissolved material such as nutrients usually flow towards riparian zones because of gravity. This means that riparian zones are not only fed by streams (along with the sediment and nutrients accompanying the streamwater), but also by nutrients via overland flow and groundwater from the adjoining terrestrial areas, which may be natural areas, or cultivated fields. These nutrients feed the plants. The vegetation around most of South Africa’s rivers consists of large shrubs and trees, which is distinct from the surrounding lower growing vegetation, for example
along riparian zones interactions, we need to conserve all the different elements and ensure that water and nutrients continue to supply these areas. Natural disturbance Contrary to what we might expect, riparian plants and animals are dependent on occasional disturbances such as floods and fire. Floods may occur every year and may spread the seeds of riparian plants and wash them out onto sandbanks where they can germinate. Large floods can uproot trees and create microhabitats on the banks where branches and sediment are deposited, which in turn can be recolonised by plant communities and used as habitats by riparian animals, such as small mammals and birds. Juvenile lizards and various invertebrates such as spiders seek shelter within these areas during vulnerable stages of their life cycle. Floods also redistribute sediment and nutrients within the river, which is especially important for human communities living downstream, where crops are dependent on these life-giving resources. A good example are the farmers who use the sediment in the Nile River to farm vegetables. Fire is also known to redistribute nutrients by converting organic material to ash, from which phosphorus and nitrogen are put back into the soil for plant growth, and also deposited downstream. In riparian zones, fires occur less frequently than in some of the
Figure 2: A gallery forest riparian zone, in the dry season, in Kruger National Park, Mpumalanga province. Here, the riparian zone is easily separated from the surrounding matrix, through distinctly taller, denser and greener vegetation. These are important areas for elephants, especially in the dry season. Image: SM Jacobs
Figure 4: A dragonfly’s transition from water-living nymph to a terrestrial adult stage, taken at Wit River in the Bainskloof Valley, Western Cape. Image: CJ Crous
adjoining terrestrial ecosystems such as the fynbos or grasslands. However, most riparian plants are adapted to the effects of fire, and can regenerate by re-sprouting from the base or from branches. ▲ ▲
Karoo bushes and grasslands. This can easily be seen on aerial and satellite pictures (Figure 3). Riparian zones contain many plant and animal species that are adapted for wet conditions. Plant species such as reeds, bulrushes and some trees have special cells called parenchyma that possess large air pockets so the organs that are covered by water for part of the year can be supplied with oxygen. Because riparian zones are rich in nutrients and typically flooded, the vegetation grows dense and tall. This environment acts as a habitat for a host of different animal species – ranging from small invertebrate animals such as dragonflies to the large predators of the African savanna. The dragonfly relies on riparian habitats to complete its life cycle – its larval stage is aquatic and requires flowing water to survive. The larvae also need shade, which makes riparian areas shaded by trees ideal. After emerging from the larval stage (Figure 4) the adult dragonflies then live along the riparian zone, and lay the next batch of eggs in the water. Any disturbance at this stage may interupt the life cycle. The resources available in riparian environments attract large numbers of different animal species, and frequently support several trophic levels. In savannas, herbivores are attracted to the lush green grass in riparian zones, which in turn attracts predators such as lions and leopards. Because riparian zones have such complex and dynamic trophic
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Figure 5: Above: Large herbivores such as elephants. Right: hippopotamus use riparian areas, as seen here in Kruger National Park in the Mpumalanga province. Image: SM Jacobs
What makes a riparian zone useful? Riparian zones fulfil several functions that are important to human wellbeing and quality of life. People have long relied on riparian areas for the abundant food, water and material resources they supply. Since riparian zones are usually found at the bottom of valleys, they have 1) more fertile soil, with more nutrients available such as nitrogen and phosphorus, and 2) a greater availability of water. This makes riparian zones attractive for agriculture, including crop production and for grazing livestock. A good example of this is the Orange River valley (e.g. Kakamas and Keimoes) where farmers are using the riparian environments in a very dry region to produce the grapes and wines sold locally and internationally. Without the riparian zone, this agricultural activity would not be possible within this semi-desert environment. Subsistence farmers also use the areas near rivers to grow maize, beans and other crops for their families. Many animals also congregate around rivers, and use riparian zones for food and shelter. Large animals in savanna ecosystems use the rivers extensively during the dry season (Figure 5). Without the nourishment provided by the river and its riparian zone, these animals would not be able to survive in these harsh climates. Several large antelope such as nyala, bushbuck and kudu use riparian zones as corridors to move along rivers, while enjoying the relative cover available in these areas to hide from predators such as lions. The Cape clawless otter uses riparian zones extensively, while the riverine rabbit, a critically endangered animal, is almost entirely dependent on Karoo riparian areas for its survival. Of course, bird species are a major feature of riparian zones. Smaller birds may use these areas to feed, hide from predators, nest and rear young. The larger predatory birds
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use the areas for nesting and hunt the smaller animals within the zone. Any degradation of riparian zones will endanger a whole variety of plants and animals that depend on this narrow green ribbon along rivers, wetlands and estuaries. Humans are not immune to the effects of riparian zone degradation, with consequences for agriculture and other economic activity. Ecosystem services Riparian zones prevent river pollution by trapping potential pollutants as they move downhill into the rivers. Complex interrelationships between microorganisms, plants and nutrients in riparian areas help to break down contaminants discharged into the environment. This is particularly important close to farms, where fertilisers are used and there is the potential for the accumulation of excess nutrients such as phosphorus and nitrogen, as well as pesticides, sediments and particulate matter. The usable matter, such as phosphorus, gets taken up by riparian plants and animals, while soil processes convert excess nitrogen to nitrogen gas, which is released back into the atmosphere. Because of the moist conditions, there is heavy decomposition of plant organic matter and some of this decomposed matter will be removed during flooding. Healthy riparian zones help to filter and purify water for drinking, irrigation and recreation. Riverine areas are also an effective buffer against flood damage. Floods are natural events in river ecosystems. The vegetation and soils in riparian zones soak up and store water during high rainfall events, reducing the speed of the mass of flood water and stabilising stream banks and preventing surface erosion. If the
natural riverside vegetation is replaced with vegetation that is less dense or of a different structure this reduces the ability of riparian zones to reduce the impact of floods (e.g. Figure 6). This can lead to catastrophic flooding in damaged areas. Lastly, riparian areas are focal points for education, recreation and simple enjoyment – bird watching, angling, water sports and so on. But if we transform the riverside areas by putting up picnic areas and camping sites, this may also damage the natural ecosystem. Degradation and conservation of riparian zones Anthropogenic disturbances
Riparian areas are threatened by expanding urban and agricultural neighbourhoods, which can lead to large-scale destruction. South Africa is a water-scarce country with an average rainfall of around 450 mm per annum compared with a global average of 860 mm. With only 8.6% of rainfall available as surface water, fresh water is a limiting resource, making its conservation vital. Human-induced disturbances (anthropogenic disturbances) are increasing, placing enormous pressure on South Africa’s current water situation. One of the main pressure points is rising population numbers. By 2025 there will be approximately 60 – 75 million people in South Africa, compared with 50 million today. This will place huge pressure on our already strained water resources. The tragedy is that most of South Africa’s surface and groundwater resources have already been developed, so it is essential to develop strategies for sustainable water management. Climate change is likely to
exacerbate South Africa’s water shortages, with a predicted 195 000 km2 (16% of the country) likely to experience increasing water shortages as the country dries. This would reduce riparian biodiversity further and lead to reduced water quality. Alien invasive plants (IAPs) are also threatening South Africa’s riparian zones, particularly alien trees such as species within the genera Pinus and Eucalyptus. These invasions reduce water yields from catchments and affect riverine functioning and biodiversity (see Figure 7). Sustainable forestry policies today do not allow exotic timber to be planted in the riparian zone of the catchment. However, the problem of runaway invasion of certain species into the riparian zones still exists, especially Acacia mearnsii (black wattle). Models predicting future consequences of a lack of management of IAPs and water resources in the Western Cape indicate that if the current growth of alien plants goes unchecked for 100 years, some species might invade up to 62.4% of the catchment areas. This would cause a loss of about 87 million m3 of water. This translates to a 34% decrease in annual water availability for the City of Cape Town municipal area. This alien biomass needs to be removed to conserve water quality and sustain crucial ecosystem services. What can be done to restore riparian zones?
South Africa has ratified the Convention on Biological Diversity’s 2010 target, which was to significantly reduce the loss of biodiversity in the country by that year. Government and scientific agencies have attempted to lessen the effects of factors such as IAPs over the year, through different conservation initiatives.
One such is the Working for Water (WfW) programme that started in 1995. This project set out to eradicate IAPs in the riparian zones, to maintain and restore ecosystem services, and to improve the livelihood of impoverished people by providing jobs. The programme is locally and internationally renowned as being truly proactive in the battle against biodiversity loss and the subsequent water losses. Government has also improved outdated policies, such as the Conservation of Agricultural Resources Act (Act no. 43 of 1983, amended March 2001), to ensure that valuable water resources are properly protected by law, particularly the removal of thirsty IAPs from riparian zones. All IAP plants growing within 30 m of the 1:50 flood line of a river or water body must be removed. The onus is on responsible land management and usage, which requires public awareness of the issues, so that people can take responsibility for the conservation of water resources by removing alien plants from their properties, preventing fires in riverine areas and reporting excessive littering and pollution in these areas. People need to understand the value of riparian zones and take part in the conservation of this life-giving resource that is so easily taken for granted. ❑ Casparus Crous is a PhD student at the Department of Conservation Ecology and Entomology at Stellenbosch University. Dr Shayne Jacobs and Professor Karen Esler are at the same department, and also affiliated with the Stellenbosch University Water Institute. Professor Esler is also a core team member of the Centre for Invasion Biology at Stellenbosch University.
Figure 6 (Above left and right): Soil erosion as a consequence of removing natural vegetation and replacing it with alien vegetation. This has detrimental effects on water quality and quantity. Image: SM Jacobs
Figure 7: A schematic diagram of the effect of black wattle invasion on pristine riverine or riparian areas. Image: CJ Crous Suggested reading Davies B and Day J. Vanishing Waters. Cape Town: University of Cape Town Press, 1998. Meadows ME Global Change in South Africa. Geographical Research 2006. 44: 135-145 New M. Climate change and water resources in the southwestern Cape, South Africa. South African Journal of Science 2002; 98: 1–8 Otieno FAO and Ochieng GMM. Water management tools as a means of averting a possible water scarcity in South Africa by the year 2025. Water SA 2004; 30: 120-124 Walmsley RD, et al. Freshwater systems and resources. Pretoria: National State of the Environment Report, Department of Environmental Affairs and Tourism, Republic of South Africa, 1999. More information can also be found at: Department of Conservation Ecology and Entomology - http://consent. sun.ac.za/ Stellenbosch University Water Institute - http://www0.sun.ac.za/water/ Centre for Invasion Biology - http://academic.sun.ac.za/cib/
Quest 7(4) 2011 41
Climate change and our coasts Nikki James gives us some insights into the impacts of climate change on the South African marine and coastal environment
he South African Environmental Observation Network (SAEON) was approached by the South African National Biodiversity Institute (SANBI) to coordinate the marine component of South Africaâ€™s Second National Communication under the United Nations Framework Convention on Climate Change, which was published in 2010. The second communication by design is an integrated, relatively short document that provides an overview of climate change and its implications for South Africa. A comprehensive synthesis of the current knowledge of the impacts of climate change on the South African estuarine, coastal and marine environment was produced to provide the reader with the detail behind the marine component in the second communication. The outcome is a detailed report: Insights into impacts of climate change on the South African marine and coastal environment (download at: http:// www.saiab.ac.za/), which was produced by 19 authors from 12 institutions. Climate impacts were assessed by (1) reviewing the scientific literature on climate change impacts on South African marine life and ecosystems in the context of known impacts elsewhere in the world, (2) summarising the key trends, impacts and vulnerabilities of ecosystems and marine life to climate change and (3) assessing knowledge gaps and the research and resources needed to better assess possible impacts. The report comprises separate chapters on: n Key climatic drivers n The Benguela system and South African fisheries n The Agulhas Current system and climate change n Trends in nearshore sea-surface temperature and circulatory systems n Reef ecosystems n Estuaries n Sandy shores n Rocky shores and kelp beds n Subtidal fishes n Coastal infrastructure
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Figure 1: Linear trend of Advanced Very High Resolution Radar Sea Surface Temperature (AVHRR SST) from 1985 to 2007. Mean 1993 â€“ 2007 absolute geostrophic velocity vectors derived from combined altimetry are superimposed (from Rouault et al. 2009).
Highlights from the report Climate change that is linked to the build-up of greenhouse gases and aerosols in the atmosphere has led to increases in surface air and ocean temperatures over the last 50 years (IPCC 2007). Nellemann et al. (2008) list climate change, pollution, fragmentation and habitat loss, invasive species infestations and over-harvesting from fisheries as the top five stressors affecting the marine environment. If climate change accelerates, the impacts on marine ecosystems from other stressors will increase and the ability of ecosystems to recover will be impaired. In addition to rising surface water temperatures, climate change incorporates changes in precipitation and evaporation rates, sea-level rise and increased frequency and intensity of storms, ocean circulation, winds and CO2 concentrations, all of which will have profound consequences for marine and coastal ecosystems (Roesig et al. 2004). This report considers the possible influences of climate change on South Africaâ€™s estuarine, coastal and marine environment. Some of the key trends identified in the report include: n Climate variability over southern Africa is complex, with a multitude
of forcing factors that interact in a way that means that southern Africa experiences strong ocean influences on its weather and climate patterns. Unfortunately, we are far from being able to provide successful predictions of the climate in the oceanic region. n The Benguela ecosystem and associated fisheries are vulnerable to changes in the frequency of harmful algal blooms, distribution of fishery resources, fishery landing points, stock levels and recruitment. Research has shown that the system is highly productive, complex and variable, and it is extremely difficult to attribute trends to climate change as opposed to other drivers. n One of the strongest trends (over the past 50 years) has been warming at the northern and southern boundaries of the Benguela system, with potential consequences for increased hypoxia on the Namibian shelf. There has also been a long-term increase in southerly winds, which induce upwelling in the southern Benguela, with modulation over decadal time scales. n Observations of the Greater Agulhas region are very limited. The Agulhas Current has a marked influence on the local atmosphere, which can at times make a major difference to terrestrial synoptic systems,
Q Climate change
Figure 2: Galaxea astreata overrun a bleached reef. Image: Michael Schleyer
Figure 4: Umhlanga Rocks – inappropriate (too close to the beach) coastal development is taking out the primary dunes and breaking down the links in the littoral active zone.
Oscillation (ENSO) event, unlike elsewhere in East Africa, but quantifiable bleaching occurred during an extended period of warming in 2000. n The corals have also shown changes in community structure, involving an increase in hard coral cover and reduction in soft coral cover, resulting in a 5.5% drop in overall coral cover. These ‘silent’ effects of temperature increase do not appear to have been reported in the literature. Eutrophication is defined as an increase in the rate of supply of organic matter in an ecosystem.
n The degradation of many of South Africa’s estuaries, due to global change drivers, such as eutrophication, fishing and harvesting, freshwater abstraction, sedimentation and mouth manipulation, has been well documented. Documented changes that can be attributed to climate change are, however, far more limited and generally linked to range extensions of certain tropical taxa due to changes in water temperatures, e.g. estuarine fish in the East Kleinemonde and Mngazana Estuaries in the Eastern Cape. n In terms of climate change, South Africa’s sandy shores are primarily vulnerable to sea-level rise and to the increased frequency of high-intensity coastal storms in those areas where the beaches are constrained by hard structures such as sea walls, coastal infrastructure or buildings.
Figure 3: Global warming in a South African context may result in sea-level rise and, together with the more frequent occurrence of extreme weather conditions, could have implications for estuarine ecosystems. Top and bottom: a flooded caravan site on the banks of the Great Fish River and storm surf conditions resulting in a major overwash event in the temporarily open/closed East and West Kleinmonde Estuaries, Eastern Cape, September 2008. Image: Dr Paul Cowley, SAIAB When coastal development has been inappropriately located too close to estuaries and beaches, the normal response of systems to migrate landward in response to sea level rise is prevented, leaving them trapped in what has been termed a ‘coastal squeeze’.
enhancing their intensity. Apart from these very local and coastal effects, the Agulhas Current system and sea-surface temperatures in the South-West Indian Ocean have been shown to influence regional atmospheric circulation patterns and attendant rainfall patterns. n Since the 1980s the sea surface temperature (SST) of the Agulhas Current (measured from satellite SST data) has increased significantly (up to 0.7 ºC per decade) due to its intensification in response to changing wind patterns in the South Indian Ocean. n The satellite data indicates that along the west coast near-shore, sea surface temperature is cooling between -0.2 and 0.5 ºC per decade, with isolated small-scale pockets of cooling in the region between Cape Agulhas and Cape St Francis (South Coast) of about -0.2 ºC per decade. A larger region of cooling, ranging from -0.2 ºC to -0.7 ºC was identified between East London and Port Elizabeth, centred in the Port Alfred dynamic upwelling cell. n Coral reefs occur in South Africa within the iSimangaliso Wetland Park (iSiWP), in northern KwaZuluNatal. A long-term monitoring programme was started on these reefs in 1993. Sea temperatures rose by 0.15 °C per annum at the site up to 2000, but have subsequently been decreasing by 0.07 °C per annum Insignificant bleaching was encountered in the region during the 1998 El Niño Southern
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Figure 6: Juvenile Chrysoblephus laticeps (Roman seabream) feed in shallow-water beds of seaweed where they are vulnerable to climate-induced changes. Image: A Götz
In these developed regions of South Africa some sandy beach ecosystems are at risk of being lost through inundation and erosion as a result of ‘coastal squeeze’. n Other consequences of sea-level rise for sandy beaches in South Africa may include: increased erosion, dune blowout formation; intensified flooding; and increased saline intrusion into coastal aquifers. n Within the rocky intertidal ecosystem there have been shifts in population abundance and changes in the proportions of cold water and warm water affinity species within the community. This implies potentially significant changes in community functioning and dynamics, probably linked to References IPCC (Intergovernmental Panel on Climate Change). Climate change 2007: The physical science basis. Contribution of working group I to the fourth assessment report of the Intergovernmental Panel on Climate Change. Solomon SD, Qin M, Manning Z, Chen M, Marquis KB, Averyt M, Tignor, Miller, HL (eds). 2007. Cambridge: Cambridge University Press. Nellemann C, Hain S, Alder J (eds). In dead water: merging of climate change with pollution, over-harvest, and infestations in the world’s fishing grounds. 2008. GRID-Arendal, Norway: United Nations Environment Programme. Roesig JM, Woodley CM, Cech JJ, Hansen LJ. Effects of global climate change on marine and estuarine fishes and fisheries. Reviews in Fish Biology and Fisheries 2004; 14: 251–275. Rouault M, Penven P, Pohl B. Warming in the Agulhas Current system since the 1980s. Geophysical Research Letters. 2009; 36: L12602, doi:10.1029/2009GL037987.
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Figure 5: The changing face of rocky shores. Top and middle: On the west coast in particular, three major invaders dominate the species assemblages: Balanus glandula, Mytilus galloprovincialis and Semimytilus algosus. Bottom: Remnant Perna perna population in False Bay; a small population of adults left behind following a range edge recession over the past 20 years. Image: Charles Griffiths
cooling of near-shore sea surface temperatures in the cool-temperate region and adjacent transition zone and shifts in circulatory and upwelling patterns. n There is currently little evidence for climate change impacts on subtidal fishes in southern Africa. A southward shift in the distribution of the west coast dusky kob (Argyrosomus coronus) from southern Angolan into northern and central Namibian waters was seen between 1995 and 2009. This corresponded with a 0.8 – 1.0 ºC increase in sea surface temperature per decade during a similar period. n Consequent to a rise in sea-level, South Africa has, in general, very little adaptive capacity in developed coastal areas, other than relatively expensive upgrades or replacements to existing coastal infrastructures. Sea level is rising around the South African coast (Mather et al. 2009) in agreement with current global trends, but there are regional differences. With a rise in sealevel and a possible increase in the frequency and intensity of sea
Figure 7: Damage from the March 2007 storm in KwaZulu-Natal by high sea levels and large waves; Top: Beach facilities on the lower South Coast; Middle: Flooding of George Hulett Place, Salt Rock; Bottom: Inundation of North Beach Pier, Durban. Image: SAIAB
storms, the South African coastline is expected to experience: increased exposure to more intense and more frequent extreme events; increased saltwater intrusion and raised groundwater tables; greater tidal influence; increased flooding, with greater extent and frequency; and increased coastal erosion. In summary, although there is evidence of climate change impacts on South Africa’s marine and coastal environment, long-term decadal datasets, which are limited, in-situ monitoring, modelling and experimental research is required to better assess possible impacts and design appropriate mitigation measures. It should also be recognised that in South Africa there are significant global change stressors such as pollution, fragmentation and habitat loss, invasive species infestations and over-harvesting from fisheries impacting on the marine environment (over short and long time scales) that require ongoing research and mitigation. ❑ Dr Nikki James is an aquatic biologist at the South African Institute for Aquatic Biodiversity. Her research is focused on global change and she edited the report together with Dr Juliet Hermes of the South African Environmental Observation Network (SAEON).
Flagship Marine Science Programmes: Addressing Climate Change
Global Role Current
Research is showing an increasingly important link between global climate and the Agulhas Current. Agulhas Rings, which are shed from the Agulhas Current Retroflection, travel into the North Atlantic, providing inputs of warm, salty water (Agulhas leakage) which strongly affects the Meridional Overturning Circulation (MOC), and ultimately, the climate of the eastern seaboard of the USA and much of Northern Europe. This has sparked a huge amount of interest in the oceanography of this region (both current and historical) along with the upstream drivers of the Agulhas Current (Mozambique channel eddies, East Madagascar Current and South Equatorial Current).
“The other CO2 problem” - Ocean Acidification
ACEP’s focal areas include providing science platforms for the marine research community, Capacity Building with an emphasis on redress and transformation and a rigorous scientific research programme with a focus on coelacanths, conservation, genetics, palaeoclimatology and the oceanography and ecosystem of the eastern coast of South Africa.
The effect of increasing temperatures and levels of carbon dioxide on marine life such as these jellyfish is poorly understood, but is likely to be detrimental to entire ecosystems
The Agulhas and Somali Current Large Marine Ecosystems Project (ASCLME) The UNDP supported GEF financed ASCLME Project, which will run until 2013, is introducing an Ecosystem Approach to the management of marine and coastal resources throughout the western Indian Ocean region.
Catalysing Regional Through Partnerships
ACEP and ASCLME have attracted a wide range of international partners. Through such partnerships and the benefits they bring, these two relatively small research programmes have vastly increased their capabilities and catalysed a regional research process which has: • reinvigorated regional marine science, • undertaken internationally recognised cuttingedge research, • built an international network of marine scientists, • made available vital research platforms and • resulted in the deployment of a suite of critical monitoring instrumentation throughout the region.
ACEP led sampling of marine life, like this foraminiferan Spiroloculina ornata, is helping to unlock the palaeoclimate records of the Agulhas Current region 0
ACEP/ASCLME Cruise stations 2008 - 2010
2008 Cruise stations
2009 Cruise stations 2010 Cruise stations 10°S line Agulhas Return Current ARC Mooring
Ocean acidification refers to the effects of increasing levels of carbon dioxide, which are caused by human activity, being dissolved in the oceans. This creates carbonic acid and makes the pH of the oceans
1,000 Nautical Miles
The research community has recognised these gaps and is building a network of global ocean observation systems, which are helping to update our understanding of this system and to detect and monitor the rate of change.
ACEP’s ROV provides a cutting-edge research tool to South African marine scientists
The upper three meters of ocean can store approximately the same amount of heat as the entire atmosphere, yet the oceans have an average depth of around two kilometers, representing a vast storehouse of heat. However, this enormously important part of the world’s climate system is poorly understood and poorly monitored; all the traditional research cruises around the world provide fewer data points (from CTD casts) than a single weather station reporting temperature once an hour.
ACEP is South Africa’s cutting edge flagship marine science project. During the past four years ACEP has focused its attention on research within South Africa’s maritime borders, whilst its partner, the Agulhas & Somali Current Large Marine Ecosystems (ASCLME) Project, has continued ecosystem research begun during the first phase of ACEP around the western Indian Ocean.
Scientists tell us the world’s oceans are getting warmer – why is this significant?
The African Coelacanth Ecosystem Project (ACEP)
Mad aga sca
The oceans represent a vast storehouse and transport system for heat and water, which are vital to the overall climate system. Oceanographic research is demonstrating that the patterns of flow within the oceans are often more complex than previously understood, which has important ramifications for climate models. These current systems themselves may also be subject to change through global warming.
The oceans have long been neglected in the drive to understand the earth’s climate system and other effects of increasing levels of greenhouse gases caused by human activity on earth, notably carbon dioxide.
increasingly acidic. The long term effects and critical levels are still areas of active research, but are likely to affect entire ecosystems and threaten species which depend on the secretion of calcium carbonate to create their skeletons, including many corals, crustaceans and plankton species – and, in turn, those species which depend on them, including fisheries resources and humans - through reduced availability and quality of ecosystem goods and services.
The Relevance of Oceanographic Research to Climate Change
Mauritius La Reunion (France)
Prince Edward Islands (South Africa)
ASCLME Agulhas and Somali Current Large Marine Ecosystems Project
R/V uKwabelana provides an invaluable, relatively low-cost platform for marine research
Image: Rebecca Garland
Acid mine drainage â€“ can it affect human health? Acid mine drainage has known adverse effects on the environment. But can it affect human health? Rebecca Garland discusses the issues.
s you saw in an article in Quest 7(2), acid mine drainage (AMD) can be formed in some of the mining areas of South Africa by the reaction of water and air with reactive minerals containing sulphur. The resultant AMD is an aqueous mix of inorganic compounds and heavy metals, although the exact composition of the AMD can vary from site to site. AMD is found around some coal, gold and copper mines in South Africa.
A warning sign near an open-cast mine.
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Image: Rebecca Garland
The release of acid mine drainage into the environment AMD is created at mining sites or areas where tailings dumps are present and if it is not contained or treated in the mining area, it can be released into the environment as polluted water. This polluted water, once it is decanted from the mines, can then travel through the ecosystem through
both surface waters and groundwater. This release has the potential to have a serious impact on both the ecosystem and on any humans who may come into contact with it. However, while there is research documenting the adverse effects of AMD in the ecosystem, much less is known about the potential impact on human health. In order for humans to be affected by the pollutants in AMD, they first need to be exposed to the pollutants. AMD enters the environment as polluted water, either through surface water such as rivers or through groundwater. As the water moves through the ecosystem, the pollutants in AMD can then enter other parts of the ecosystem. For example, AMD pollutants in a river could be deposited and end up in the river beds. Also, if AMD-contaminated water is used for irrigating crops, then there is a risk that the soils and
Q Environmental Science
plants can become polluted. And, if an animal drinks the polluted water or eats the polluted plants, then there is a risk that the animal can take up the pollution as well. Thus, there are many ways that people can potentially be exposed to the AMD pollutants. However, it is not fully understood if and how people are exposed in South Africa. People could be directly exposed by swimming in polluted water or soil or by consuming polluted water. And people can indirectly be exposed to AMD by consuming contaminated plants or animal products such as meat and milk. There are many potential exposure pathways. However, very little is known about how AMD pollutants move through the environment and how much risk there is of human exposure and if that exposure will cause health problems. We also do not know if people’s health could be affected at specific concentrations of pollutants. Cause for concern What we do know is that many of the components and pollutants in AMD are dangerous to humans. For example, AMD can contain contaminants such as arsenic, cyanide, mercury, lead and uranium. These are known to be very dangerous to humans, causing illnesses ranging from skin irritation, kidney damage and neurological diseases to cancer. We also know that many of the heavy metals that may be present in AMD are known to accumulate in plants and animal tissue as you move up the food chain. For example, arsenic has been found to concentrate in the leaves of plants near mining sites. This accumulation can be dangerous because continued exposure leads to high levels of the pollutant in the organism’s tissues, potentially causing damage. This is still an area of research with many questions and current projects are concentrating on how people can be exposed to AMD, and if they are, what the health impacts could be. ❑ Rebecca Garland is a Senior Researcher at the CSIR in Pretoria. Her interests include environmental health research, which focuses on how human health is affected by environmental factors (such as AMD, air quality and climate change).
Animals may drink polluted water.
Image: Rebecca Garland
Surface waters can transport acid mine drainage.
Image: Rebecca Garland
Bioaccumulation Bioaccumulation is the word used for the accumulation of a substance (e.g. chemicals, pesticides, heavy metals, etc.) in an organism. This accumulation occurs when the organism absorbs the substance at a higher rate than it is lost. The high levels of mercury that can be found in fish is an example of bioaccumulation. Mercury that has been released into the environment can be converted into methylmercury by bacteria in soils and plants. Methylmercury can then be taken up by aquatic plants and animals. And when fish eat these smaller organisms, the methylmercury can build up in that fish’s body. Then when an even bigger fish eats these smaller fish, the methylmercury can build up in the bigger fish’s body. This can continue up the food chain, eventually impacting human health when contaminated fish are eaten. The US Environmental Protection Agency says that eating contaminated fish accounts for almost all of the human exposure to methylmercury in the US. For more information on mercury exposure, see the article ‘Mercury exposure – are we at risk’ in Quest 6(1) 2010.
Quest 7(4) 2011 47
The way things really are The Magic of Reality: How we know what’s really true. By Richard Dawkins. Illustrated by Dave McKean. (Cape Town and London. Random House Struik. 2011) I have been reading Richard Dawkins since his first book The Selfish Gene was required reading for my undergraduate biology degree. That was pretty spectacular – and all the popular science books that have followed have been equally good. But The Magic of Reality goes a step further. Dawkins is famous for his inroads into religion, which he regards as a form of myth and superstition and he has made many enemies as a result. In this book he specifically looks at the myths that surround natural phenomena and then explains what the reality is – and the magic that is this reality. The book starts with a clear explanation of what reality is – and how it is science that informs that reality. Dawkins then takes the reader on an energetic and fascinating exploration of the myths surrounding such issues as ‘Who was the first person?’, ‘When and how did everything begin?’ and ‘Are we alone?’ – starting with the various myths and stories that are prevalent in all cultures and following with an explanation of the science. The book is lavishly and beautifully illustrated in a way that is perfect to show just how magical the world around us is – without invoking myth or superstition, which are simply ways of explaining phenomena that are not understood. The Magic of Reality can be read at many levels and is suitable for children and adults – and could certainly be an excellent teaching tool for any or all of the sciences.
Forensic investigations Missing and Murdered: A personal adventure in forensic anthropology. By Alan G Morris. (Cape Town. Zebra Press. 2011) Alan Morris taught me human biology in first year medicine and anatomy in second year and his lectures were among some of the best I have ever had. So I was not surprised when I managed to finish this excellent book in one weekend. We associate forensics and forensic anthropology with television crime programmes and films and writers such as Kathy Reichs. However, the reality – although a lot less spectacular – is just as interesting. Alan Morris’s career in forensic anthropology has developed over a long period of time, born of an interest in what bones can tell us about the past, and his love of teaching means that many of his palaeoanthropology students have followed in his footsteps. The book starts with a lucid explanation of just what bones – old and young – can tell us about a person and their circumstances.
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Morris details the role of the forensic anthropologist and the various laboratory techniques before going on to relate various cases, both criminal and otherwise, that he has been involved in. Some of the most pertinent were examinations of people who disappeared during the apartheid years and whose remains were found as result of the TRC hearings. In examining these cases and the so-called muti murders, Morris skillfully emphasises how an understanding of a people’s culture is as important as anthropological and pathological knowledge when trying to understand the reasons for violent death. Forensics usually fascinates people, but forensic anthropology does not get as much press as medical forensics. This book fills that void and shows that we have such experts right here in South Africa. It also shows just how science is used in everyday life and should stimulate many young people into exploring a career in anthropology in general and forensics in particular.
Legends illustrated Water, Stone and Legend: Rock art of the Klein Karoo. By Renee Rust and Jan van der Poll. (Cape Town. Struik Travel and Heritage. 2011) The southern region of South Africa is rapidly becoming recognised as one of the main areas in which humankind evolved – and not only evolved in terms of biology, but in terms of culture and cognitive skills. Although the rock art discussed and beautifully photographed in this book may not be that ancient it is an integral factor in understanding the first peoples of the region – the southern San groups. As the author – Renee Rust – says, ‘Rock are is undoubtably one of southern Africa’s most valuable cultural hertitage items, and one of its most sensitive assets to safeguard.’ The rock art of the Klein Karoo is usually associated with water reservoirs, which is where the elders still tell of the mythical watermeide. The rock art that is shown in photographs and described in the book shows the San people’s interpretation of these myths and the intertwining of water, stone and legend. It provides a beautiful, illustrated social history of a lost people and in doing so, takes us closer to our roots.
Watery land plants Ferns of Southern Africa: A comprehensive guide. By Neil R Crouch, Ronell R Klopper, John E Burrows and Sandra M Burrows. (Cape Town. Struik Nature. 2011) If you simply look around you in most parts of southern Africa you would be surprised to see such a thick book on the ferns of the region. Ferns are plants that still depend on water for reproduction, so this arid region is an unlikely home to such an abundance of different species.
Q Books Ferns are beautiful and varied plants and this wonderful guide introduces their structure and life cycle and then provides excellent keys to the families, genera and species. Each species has a distribution map, the derivation of the name, a full description and usually a list of the features of similar species to aid in identification. There are many photographs of anatomical features and the regions in which the different species are found. For the serious botanist there are taxonomic notes and an extensive reference list. There is a comprehensive glossary and clear diagrams explaining the features of the group.
All the fowls of the air Sasol Birds of Southern Africa. 4th ed. By Ian Sinclair, Phil Hockey, Warwick Tarboton and Peter Ryan. (Cape Town. Struik Nature. 2011) All serious ‘birders’ will have been waiting for this fourth edition of Sasol and Struik’s ever popular Birds of Southern Africa. It is described as ‘the region’s most comprehensively illustrated guide’ and that is not an overstatment. The team of extremely well-known South African ornithologists have once again done their passion proud. The illustrations are excellent – a tribute to the skill of the two artists involved, Norman Arlott and Peter Hayman. This is particularly important because most of us identify birds by what we see and not by the descriptions that accompany each species. The plates have been redesigned so that they are easy to use and it is easy to compare similar species. There are more than 380 new illustrations, with simplified labels, highlighting key differentiating features. In this fourth edition the species accounts have been rewritten and now include an introduction to each group. The distribution maps have been updated to show the relative abundance of a species in each region, and also showing resident or migrant status. Sonograms are included for species that are best identified by song – a nice feature for the really serious birder.
The sky at night 2012 Sky Guide Africa South. Astronomical Handbook for Southern Africa. (Cape Town. Astronomical Society of Southern Africa and Struik Nature. 2011) You know that you are nearing the end of the year when this annual guide arrives in the post. This is an invaluable practical resource for anyone who wants to understand the night sky in southern Africa. The handbook is prepared each
year by by the Astronomical Society of Southern Africa and is aimed at novices, amateurs and professionals alike. The information covers the Sun, the Moon, the planets, comets, meteors and bright stars, with diagrams to support the text. This handbook will tell you the movement of the planets, the occurrence of eclipses, the dates of meteor showers and star and constellation indentification charts for the year 2012.
Looking at trees What’s that Tree? A starter’s guide to trees of southern Africa. By Eugene Moll. (Cape Town. Struik Nature. 2011) There are quite a few tree identification guides for southern Africa – some of them purely regional – and all of them fat, potentially intimidating books that may put off a novice. So this little book is a refreshing change and aimed at those who want to get to know our trees without burying themselves in technical detail. However, this does not mean that the book is less than scientific. There is an excellent introduction that covers the essentials of taxonomy, basic tree botany and habitat type. The book is divided by tree Family, using the simple approach of bottle-brush tree family, thorn tree subfamily and so on. The photographs are clear and emphasise the features of the tree that will allow it to be identified. There is a good glossary and a comprehensive index, which all contribute to the book’s accessibility.
Our wonderful oceans My First book of Southern African Ocean Life. By Roberta Griffiths. Illustrated by Judy Maré. (Cape Town. Sasol and Struik Nature. 2011) This is another in the My First Book of ... series published by Struik Nature with Sasol. These beautifully illustrated books are aimed at children and have a simple, fresh approach to biology and the world around us. In this book on the oceans the introduction includes the ocean food chain, which introduces children to the idea of sustainability, along with a brief explanation of why oceans are important in our lives. Each ocean creature, ranging from birds, to fish to the sea mammals and turtles, has brief notes in English, Afrikaans,. Xhosa and Zulu, which makes the books excellent tools in primary school classrooms where children are hopefully able to learn in their mother tongue. This should be a useful addition to every school classroom.
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Diary of events Q Shows and exhibitions Iziko Planetarium, Cape Town For the December-January school holidays!
Magic Milo and the Astronaut One day Magic Milo and his friend, Sammy Starfish, meet Major Tom who makes their dream come true by taking them on a magical trip into space. Join us and discover what it's like to be an astronaut! 10 December – 12 January Monday to Friday – 11:00, 12:00 & 15:00 Saturday – 12:00 & 15:30 Sunday – 12:00 & 15:30 (excluding 25 December) Especially for children aged 5 – 12
Are you a creative thinker? Then join our academic profile on offer … • The vision of the North-West University’s Potchefstroom Campus is to become a research-directed campus where excellence in both teaching-learning and research are mutually reinforcing.
For teenagers and adults...
The Sky Tonight An interesting live lecture on the current night sky is presented every Saturday and Sunday. You will receive a star map and be shown where to find the constellations and planets that are visible this month. Saturday – 13:00 Sunday – 13:00 16 June – 13:00 Suitable for teenagers and adults
• The North-West University (NWU) is an innovative institution, offering research in a structured and multidisciplinary environment organised into 22 research entities. This focused approach adopted by the NWU has resulted in increased research performance over a number of years. • An atmosphere of creative thinking is conducive to a strategy of expanding the NWU’s current fields of expertise or areas that are identified of being of critical importance to the country.
2012: the end or the beginning?
BLACK KHAKI 082404
The famous Mayan Long Count would seem to indicate that, after three failed worlds, we are living in the fourth – and that will come to an end (perhaps) on 22 December, 2012. Whether the Long Count defines the end of the world or not, the astronomical calculations that led to it are fascinating and indicate an astounding and accurate observation of those heavenly bodies that form part of the universe around us. Starts 10 December Monday to Friday – 14:00 (excluding the first Monday of the month, excluding school holidays) Tuesday evening – 20:00 (& sky talk) Saturday – 14:30 Sunday – 14:30 (excluding 25 December) Suitable for teenagers and adults Table Mountain is more than a famous landmark – it is the only geographical feature on Earth to
NORTH-WEST UNIVERSITY YUNIBESITI YA BOKONE-BOPHIRIMA NOORDWES-UNIVERSITEIT
44 Quest 7(3) 2011
Kirstenbosch Botanic Gardens Room to Grow Wednesday Talks Every second Wednesday (started 19 January 2011). 10:30-11:30. Free entry, but garden entry fee applies. Booking not necessary. Venue: Sanlam Hall (Gate 2). Free talks by horticultural experts on gardening and horticultural topics. Contact: Cathy Abbot Tel: 021 464-6440, Email: firstname.lastname@example.org
Scifest Africa 2012 14–20 March 2012 – Science rocks!
Innovation through diversity ™
Talks, outings and courses
• High profile intellectuals differentiate, identify and distinct the activities of the NWU in delivering Masters, Doctorate and post-doctoral fellows that is complementary to other research nationally, internationally and contributing towards the development of the next generation of academics.
To view our fields of expertise, visit the website and/or mobisite Office of the Vice-Rector: Research and Planning 018 299 2606 email@example.com nwuresearch.mobi nwu.ac.za
be represented as a constellation in the sky! Our planetarium presentation explores the remarkable geology and environment of Table Mountain – and the southern skies centred on its celestial counterpart. 12 December – 10 January Monday to Friday – 13:00 Suitable for teenagers & adults Planetarium entrance fees: Adults 19 years and older: R25,00 • Children, students and SA Pensioners: R10,00 • Booked school groups: R6,00 per learner. The Planetarium reserves the right to change or cancel advertised shows without prior notice. Closed for maintenance. The Iziko Planetarium is closed for maintenance on the first Monday of the month, excluding school holidays.
Scifest Africa is South Africa’s National Science Festival and aims to promote public awareness and engagement with science, technology, engineering, mathematics and innovation (STEMI). The project consists of two components, namely the annual week-long National Science Festival held in Grahamstown in March every year, as well as a range of local, regional and national outreach programmes implemented around the country throughout the rest of the year. Scifest Africa 2012 will take place in Grahamstown, Eastern Cape from 14-20 March 2012 and we invite you to join us and make this the festival that rocks all festivals. The theme for Scifest Africa 2012 is ‘Science rocks!’ and will explore Earth sciences, archaeology, palaeontology, astrobiology, GIS, chemical and civil engineering, music ... and any other -ology or -graphy you can think of that has anything to do with rocks. Look out for the Scifest Africa 2012 Programme on our website (http://www.scifest. org.za/) at the start of the new year, or e-mail us at firstname.lastname@example.org, should you wish to be added to our mailing list.
Honorable ministers, special guests and speakers with the medal winners.
Aspiring scientists achieve top honours in Eskom Expo for Young Scientists
fter months of competition, nailbiting regional finals and intensive examination and appraisal by a panel of judges, South Africa’s latest group of aspiring scientists were honoured for their achievements at the national finals of the Eskom Expo for Young Scientists on 8 October 2011. Walking away with the top award as South Africa’s leading young scientist was Palesa Masuku of JM Ntsime High School in Moses Kotane East, in the North West Province, who will soon be winging her way to an international science fair where she will have the opportunity to compete internationally against some of the world’s best young achievers in science, technology, engineering, mathematics and innovation. Emerging from a pool of 725 finalists, comprised of Grades 6 - 12 learners, Palesa scooped the award for her project entitled Marula Fruit, which was also a joint winner in the Eskom Best Female Project, and is focused on using the fruit of the marula as an alternative source of energy. At a special awards ceremony held on 7 October 2011, the other winners of the Eskom categories were Carrie-Ann Urquhart of St Andrew’s, Welkom, joint winner of Eskom Best Female Project; Brandon Inkley and Hyeok Choi of Rand Park High School in Johannesburg for Eskom Best Energy Efficiency Project; Abongile Hlaleni and Khumbulani Ntshidi of Kayamandi High School in Stellenbosch for Eskom Best Development Project; Lana-Marie Malan of Hoërskool Brits and Thesan Appalsamy of Greenbury Secondary School in KwaZulu-Natal, joint winners of the Eskom Best Energy Project. These learners were each presented with a Dell Inspiron 1018 netbook. The Eskom Best Rural High School was awarded to JM Ntsime High School and the Best Rural Primary School was Phuthaditjhaba Intermediate School in QwaQwa, near Bethlehem in the Free State.
Minister Naledi Pandor presenting the gold medals. Image: Eskom
Palesa Masuk, overall winner of the Eskom Best Female Project. Image: Eskom
Each of the winning schools received mobile science kits valued at over R25 000. At the national finals of the Eskom Expo for Young Scientists, learners from 28 competing regions were brought together at the Birchwood Hotel and OR Tambo Conference Centre in Johannesburg to take part in a three-day adjudication process of 532 projects that ended with the announcement of the winners today. Also competing were learners from Mexico. For the first time in 31 years of this annual competition, the number of female participants exceeded that of males. In the finals, 380 girls and 345 boys competed, proving that when it comes to technical fields of study, the girls can more than hold their own. The special awards ceremony was addressed by the guest of honour, Director
of Curriculum, Innovation and E-Learning at the Department of Education, Mr Phil Mnisi, with the formal prize-giving ceremony that completed the process attended by Minister of Science and Technology, Ms Naledi Pandor and Deputy Minister of Public Enterprises, Mr Ben Martins. Dr Steve Lennon, Executive Director: Eskom International and Eskom Expo for Young Scientists’ champion, said that the event had been characterised by a high standard of entries. In many cases, he said, the entries had been inspired by problems within communities. ‘Many of the entrants addressed these problems creatively and devised ingenious solutions for them. The Eskom Expo this year proved beyond doubt that South Africa has learners with the ability and scientific interest to become leaders in the technical fields in years to come. ‘All learners taking part in the Eskom Expo for Young Scientists have illustrated perfectly why this exposition was conceived 31 years ago, and why Eskom has been committed to supporting this science fair for the past eleven years. We are proud to have once again been part of the process to help unlock the potential scientific, technological, engineering, mathematical and innovative talent of South Africa’s young minds. ‘The fact that the Eskom Expo is keenly anticipated and attracts the attention of bright minds from both city and rural schools in all provinces of our country, proves that interest in the technical fields as a career is growing steadily,’ Dr Lennon said. ‘We recognise that South Africa’s development and future growth is inextricably linked with scientific innovation. The youth of today harbour the potential to generate new processes, foster growth and change how we live for the better, which is why we continue to support an event that facilitates these advancements,’ concluded Dr Lennon.
Quest 7(4) 2011 51
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Q Back page science Speedy 3D X-rays in the operating room Having an operation always places strain on patients, and this is especially true of complicated operations. Surgeons use 3D X-rays to check the results before the patient has left the operating room. This does help to avoid possible complications, but it also means interrupting the surgery. Fraunhofer researchers are now developing a 3D X-ray system that can be integrated seamlessly into operating procedure – with no more forced interruptions.
Instant 3D X-rays.
on metallic surfaces using a small, voltageactivated stamp made out of glass. The engravings, made of tiny dots smaller than one-hundredth the width of a human hair, act as optical antennae that can identify a single molecule by picking up on its specific wavelength. The researchers filled a small syringe with glass particles and heated the needle to melt the glass inside. They then pressed the molten glass onto a master pattern, forming a mould that hardened when cooled. The team then pressed the glass mould onto a flat silver substrate, and applied a small, 90-millivolt electric potential above the silver layer. The voltage stimulated ions in both surfaces, and triggered the glass mould to essentially etch into the metal substrate. The group was able to produce patterns of tiny dots, 30 nanometres wide, in patterns of triangles, rectangles and, playfully, an ionic column, at a resolution more precise than nanoimprint lithography. Source: MIT
A 6 000-year-old cooking pot and wooden spoon recovered from the Åmose bog in Zealand, Denmark. Image: Anders Fischer
These 3D images allow them to check on the position of implants and fracture fragments, so as to determine the relative positions of pieces of bone or to position implants with millimetre accuracy. Researchers at the Fraunhofer Institute for Production Systems and Design Technology IPK are developing ORBIT, a 3D X-ray scanner that can be integrated into operations and does not cause any delays. The device has another big advantage: while implants and screws can cause interference in C-arm scans, ORBIT images feature far fewer artefacts caused by these metal objects because its X-ray source and its detector do not move in the same plane. Source: Fraunhofer-Gesellschaft
New glass stamp may make cheaper, more precise biosensors Advances in microchip technology may someday enable clinicians to perform tests for hundreds of diseases – sifting out specific molecules, such as early stage cancer cells – from just one drop of blood. However, fabricating such ‘lab-on-a-chip’ designs – tiny, integrated diagnostic sensor arrays on surfaces as small as a square centimetre – is a technically challenging, time-consuming and expensive feat. Now, researchers at MIT have come up with a simple, precise and reproducible technique that cuts the time and cost of fabricating such sensors. They have developed an engraving technique that etches tiny, nano-sized patterns
residues from aquatic organisms, which seemed to be from freshwater fish. Source: World Science, http://www.world-science.net
Manufacturing goes viral
A glass stamp reproduces precise, nanometre-scale etchings in silver. The original engraving, pictured above, is 10 microns wide – less than a quarter of the diameter of a human hair. Image: Kyle Jacobs
Ancient cooking pots point to gradual transition to agriculture Courtesy of PNAS and World Science staff Humans may have undergone a gradual rather than an abrupt transition to farming from fishing, hunting, and gathering, a study of ancient pottery suggests. Researchers in Northern Europe studied pots from 15 sites dating to around 4 000BC, when the first evidence of domesticated animals and plants had been identified in the region. Some of the settlements are now underwater and required divers to extract artefacts. The results showed that fishing continued to contribute to the diet after the advent of farming and domestication, the authors said; pots from coastal areas contained residues enriched for a form of carbon found in marine organisms. A fifth of coastal pots contained other biological traces of aquatic organisms, including fats and oils absent in terrestrial animals and plants. At inland sites, 28% of pots contained
Using a simple, single-step process, engineers and scientists at the University of California at Berkeley recently developed a technique to direct benign, filamentous viruses called M13 phages to serve as structural building blocks for materials with a wide range of properties. By controlling the physical environment alone, the researchers caused the viruses to selfassemble into hierarchically organised thin-film structures, with complexity that ranged from simple ridges, to wavy, chiral strands, to truly sophisticated patterns of overlapping strings of material – results that may also shed light on the self-assembly of biological tissues in nature. Source: National Science Foundation
This illustration reveals how the arrangement of molecular building blocks results in materials with unique properties, both in nature and in the laboratory. Image: Zina Deretsky, National Science Foundation
MIND-BOGGLING MATHS PUZZLE FOR Q uest READERS Q uest Maths Puzzle no. 19 The value of is (AxB)¸C. What is the value of the figure on the right?
Answer to Maths Puzzle no. 18:
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Quest 7(4) 2011 53
kids love chemistry Getting the next generations excited about chemistry is important for humankind’s future. That’s why we’ve created “Kids’ Lab” in 15 countries, where the young ones can learn about chemistry and science in a fun, hands-on way. Little students and test tubes finally getting along? At BASF, we create chemistry. www.basf.com/chemistry www.basf.co.za Tel: +27 11 203 2400
uppe marketing A05541