2013-04-15 21:33:02

7. Physical and Chemical factors for eutriphication (Group 7)


When a water system (in our case a lake) gets too much nutrient and starts to eutrophicate, the amount of chlorophyll rises. You can imagine what happens when you pour Substral on your petunias. Chlorophyll - mostly in shape of algae - starts to thrive and the water begins to look more blurry and more greenish. That's why you don't get any high secchi depths from an eutrophicated lake. When water plants and algea slowly die giving space for new individuals, the remnant falls down to the bottom. This bottom covering dead material needs to be decomposed by nature, but this takes a lot of oxygen. When oxygen is used for this purpose only, many lakebed species may die or vanish for lack of oxygen. At the same time nutrient is released again and the circle continues. So there you have a low oxygen level, a large chlorophyll amount and a small secchi depth.

Eutrophication is a system feeding itself, which makes it harder to halt. | Team Bucket, Finland