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the giant pantry

LIFE ON THE WADDENS THE EBB AND FLOW BENEATH THE SURFACE

The rich animal life on the wadden presents a lavish buffet for wading birds. At a first glance, the wadden looks barren and sterile with its vast and bare surfaces of sand, but appearances are deceptive. The ebb and flow of life beneath the surface is so immense that it is only surpassed by a few other animal societies. Compared to an average seafloor, the wadden contains ten times as many animals measured by weight, and with a total area of 4,700 km2 it is a giant pantry. The rich animal life is largely due to the tide, that twice every 24 hours brings nutrition-rich waters into the shallow Wadden Sea. Life here is based on the high occurrences of microscopic algae, especially diatoms that are the first link in the food chain. Diatoms are found not only floating in the water, but also on its surface, as well as down in the wadden. The brown color often seen on the wadden is due to these algae. Most of the teeming life is found buried in the wadden’s layers of sand and silt. On the clean sand and in the clean silt, animal life is relatively poor. The largest number of animals is found where the composition of silt is between 2 - 20 percent. Some species, such as the cockle and the blunt gaper are clearly visible if you dig just a little down into the wadden. There can be many thousands of cockles on just one square meter. Most of the animals are very tiny, but they often appear in dizzying numbers. For example,

Experience life on the waddens in ... SPRING

SUMMER

AUTUMN

WINTER

there can be more than 100 eelworms on just 1 cubic centimeter of wadden. On the surface of the wadden lives the tiny, but abundantly plentiful spire shell measuring only a few millimeters and therefore easy to miss. However, it you look closely, you will note that it is immensely abundant. On just one square meter there can be more than 120,000 spire shells. Beds of oysters and common mussels create habitats for many other organisms. Bladder wrack, for example, has found a way to gain a foothold in the strong tidal current.

The wadden’s land developers

Another abundant animal is the tiny sandhopper that, in certain places can be found in numbers of 100,000 for every square meter. The sandhopper lives in passages in the seafloor, where it consumes decomposed plant material and bacteria, which it filters from the water or collects from the seafloor. The sandhopper’s digging activity is important for the

Lasse Fast Jensen, Fiskeri- og Søfartsmuseet & Torben Kjærgaard, Vadehavscentret Translation: Nanna Mercer, Sirius Translation

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the giant pantry

The rockworm lives down in the wadden inside a U-shaped tube. chemical conversion and stability of the ocean floor. The rockworm is also important for the wadden. Testimony to this fact can be found everywhere in the shape of small piles of sand. The rockworm lives down in the wadden inside a U-shaped tube. Here it eats sand while harnessing the algae that sit on the surface of the sand. When, occasionally, it has to empty its bowel of grains of sand, it sticks its rear end out of the tube thus disposing of excrements that pile up on the surface. Each rockworm eats between 20 - 25 kilos of sand per year. The rockworm also creates a current of water through its tube, making it possible for many other organisms to live down in the sand.

A kindergarten for fish

The Wadden Sea is a reproductive area for many fish species. During the winter, the plaice spawn in the flowing waters southwest of the Wadden Sea where the ocean currents lead the larvae into the Wadden Sea, where they spend the first 2 or 3 years of their lives feasting on the huge food supply before leaving for the North Sea. Sole and herring also use the Wadden Sea as a kindergarten. Rockworms represent an important food source for the many fish and when a rockworm with its rear end out of the tube disposes of its excrements it is especially vulnerable. The fish take advantage of this, but the rockworm rear end is fashioned in such a way

Experience the wadden There are good possibilities for experiencing the wadden really close up - and there is something for every taste and temperament. If you are up to it, you can, without problems, go exploring on your own. It can be a good idea to bring a potato digger to make it easier to dig up mussels. It is quite exciting to explore the hidden life beneath the surface, but it can be dangerous to move too far out on the wadden, so you must be well prepared so you can avoid unpleasant surprises. The tide can come very quickly and it is easy to forget time when you explore life on the wadden. We recommend that you plan your trip according to the tide table prognosis and that you decide in advance what time to start on the way back. Watch out for an especially dense and impenetrable ocean fog that shrouds the wadden in a quilt that makes it very difficult to get your bearings. A compass or a GPS-receiver is therefore an important part of your equipment so you do not get lost.

that it falls off when caught by a fish. In this way, the rockworm is more frightened than hurt. It can stand losing its tail several times and this is a necessity, for inside the gut of the plaice one can find more ends than whole rockworms.

Lasse Fast Jensen, Fiskeri- og Søfartsmuseet & Torben KjÌrgaard, Vadehavscentret Translation: Nanna Mercer, Sirius Translation

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the giant pantry

The cockle is intolerant to cold and during cold winters much of the stock dies on the wadden.

A pantry for birds

The rich animal life on the wadden presents a lavish buffet for wading birds. The Wadden Sea is an important resting area for the many species of birds that migrate each year from their breeding grounds in the north to their wintering areas in the south. Every year, 12 million birds visit the Wadden Sea. Many of them stop only for a short while to stock up for their onward journey, while others stay in the area for the winter.

The passing of the year on the wadden

of food. With winter coming many species leave the Wadden Sea in favor of warmer and deeper waters. This is also true of the common shrimp that breeds in other waters. The plaice and its fry also leave the Wadden Sea during the winter. Animals that cannot move are very vulnerable during harsh winters. The cockle is also intolerant to cold and during cold winters much of the stock dies on the wadden. Come spring, fry from deeper waters will quickly repopulate the wadden, so concurrent with the warmer temperatures the animals return to the wadden. The young shrimp arrive in huge numbers and also crabs, fish and worms are part of the teeming life on the wadden.

Life on the wadden follows the changing seasons. During the summer, the animal life is rich and varied. The temperature is auspicious and there is plenty

Lasse Fast Jensen, Fiskeri- og Søfartsmuseet & Torben KjÌrgaard, Vadehavscentret Translation: Nanna Mercer, Sirius Translation

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the giant pantry

Things to do

Learn about life on the waddens here

Nature guides frequently arrange guided tours to the wadden when, among other things, they talk about the animal life and how man, through time, has lived in the Wadden Sea area. Tours and actual arrangements can be seen here: www.vadehav.dk

NaturKulturVarde Gl. Skovfogedbolig Roustvej 111 DK-6800 Varde T: +45 75 22 22 50 E: nkv@naturkulturvarde.dk W: www.naturkulturvarde.dk The Fisheries and Maritime Museum Tarphagevej 2-6 DK- 6710 Esbjerg V. T: +45 76 12 20 00 E: fimus@fimus.dk W: www.fimus.dk Vadehavscentret Okholmvej 5 Vester Vedsted DK-6760 Ribe T: +45 75 44 61 61 E: info@vadehavscentret.dk W: www.vadehavscentret.dk Naturcentret Tønnisgård Havnebyvej 30 DK-6792 Rømø T: +45 74 75 52 57 E: info@tonnisgaard.dk W: www.tonnisgaard.dk

tips for further reading

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Migratory birds in the Wadden Sea The seals in the Wadden Sea The oysters in the Wadden Sea Black Sun

About Vadehavets Formidlerforum... Vadehavets Formidlerforum is a partnership of visitor centers that mediate the Wadden Sea’s natural and cultural heritage. VFF’s main activity is to coordinate projects that highlight the nature and culture heritage of the Wadden Sea.. Learn more at www.vadehav.dk

Lasse Fast Jensen, Fiskeri- og Søfartsmuseet & Torben Kjærgaard, Vadehavscentret Translation: Nanna Mercer, Sirius Translation

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Life on the waddens  

At a first glance, the wadden looks barren and sterile with its vast and bare surfaces of sand, but appearances are deceptive. The ebb and f...

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