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
Page 1 of 4
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 Kjærgaard, Vadehavscentret
Translation: Nanna Mercer, Sirius Translation
Page 2 of 4
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 Kjærgaard, Vadehavscentret
Translation: Nanna Mercer, Sirius Translation
Page 3 of 4
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: [email protected]
W: www.naturkulturvarde.dk
The Fisheries and Maritime Museum
Tarphagevej 2-6
DK- 6710 Esbjerg V.
T: +45 76 12 20 00
E: [email protected]
W: www.fimus.dk
Vadehavscentret
Okholmvej 5
Vester Vedsted
DK-6760 Ribe
T: +45 75 44 61 61
E: [email protected]
W: www.vadehavscentret.dk
Naturcentret Tønnisgård
Havnebyvej 30
DK-6792 Rømø
T: +45 74 75 52 57
E: [email protected]
W: www.tonnisgaard.dk
tips for further reading
...
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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