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Ecology & Evolution
- in the Bog with 3i
On 4 September, as part of the present topic ”Ecology & Evolution”, 3i Bi SL+HL spent a beautiful day at the bog Bøllemosen in Jægersborg Hegn north of Copenhagen. The area contains several biotopes, including the only dystrophic (acidic) lake in the surroundings of Copenhagen. See pictures here.
The locality has an interesting story, once being a lake, which was later overgrown by marginal vegetation, which eventually covered its entire surface. The continuous growth of vegetation formed a thick layer of plants, and the resulting anoxic conditions resulted in an accumulation of dead plant material, which eventually cut off the support of water and nutrients from the old lake: A raised bog was formed. The raised bog is a very interesting habitat since it is entirely dependent on water from the atmosphere. Rain is a distillate of seawater and is therefore very poor in nutrients, and this leaves an environment where only real specialists can thrive, including Sphagnum mosses, which are the most abundant plants.
A raised bog can continue growth for millennia unless it is drained for water, but this has unfortunately happened for the vast majority of raised bogs in Denmark, except for a very few. Another important impact on raised bogs is cutting of peat for fuels. This happened in many bogs, including Bøllemosen, especially during WW1 and WW2 when supplies of coal and oil was limited. The peat cutting in Bøllemosen has resulted in the formation of a lake with very steep banks, and brown, acidic water. These conditions are very hostile against fish, leaving a habitat, with a wealth of insects and amphibians, which avoid competition and predation from fish. Even though Bøllemosen has a high protective status, it suffers from eutrophication from the atmosphere and birch trees need to be removed from the raised bog in order to avoid a too intensive transpiration of water and overshading of the special flora found there.
Our students were encouraged to design their own research project, which is a mandatory but demanding part of their diploma programme in natural sciences. Equipped with plastic bags, aquatic nets, pH paper and measuring tape they search for biological phenomena they could measure in order to get a sufficient amount of data for their report. Around noon we ate freshly grilled made hot-dogs and later we had marsh mallows before the students were released to obtain their final measurements, and around two o´clock we headed home.
Xenia has found a Filicinophyte similar to the one in her textbook:
Naja and Lærke are measuring the distance between two trees:
Angitta wears a cap, so that we can find her in case she disappears into the bog:
Emilie wonders about her research question:
Emilie has found her research question:
Jan, Melanie, Elvira and Alma are wondering how to walk through a raised bog without sinking in:
Melanie instructs Matin where to place the sausage in a hot dog:
Natalia, Lærke, Mathilde and Naja are enjoying their meal:
Mathilde, Natalia, Sofie, Monika and Elvira are enjoying jumbo-size marshmallows:
The caravan heads back towards Skodsborg Station:
By Jacob Damgaard