Eutrophication

1. Eutrophication By Oli Murphy A Team Pickles Production

2. A Definition • Eutrophication is a process whereby water bodies, such as lakes, estuaries, or slow-moving streams receive excess nutrients that stimulate excessive plant growth (algae, periphyton attached algae, and nuisance plants weeds). This enhanced plant growth, often called an algal bloom, reduces dissolved oxygen in the water when dead plant material decomposes and can cause other organisms to die. Nutrients can come from many sources, such as fertilizers applied to agricultural fields, golf courses, and suburban lawns; deposition of nitrogen from the atmosphere; erosion of soil containing nutrients; and sewage treatment plant discharges. Water with a low concentration of dissolved oxygen is called hypoxic.

3. Why it happens Eutrophication is caused by a runoff of fertiliser which increases the nutrients in the waterways that in turn increases the fertility. This means there is greater competition and a large amount of plants die. Bacteria use the dead matter in respiration, absorbing oxygen from the water so that other organisms in the water cannot respire Here is an example of an experiment in a Lake in which on one side of the boom fertiliser has been added whilst the other side has been left natural

4. How it can be overcome The most important thing is to use organic fertilisers. These break down a lot slower and so not all the nutrients are released at once reducing the plant bloom Spraying fertilisers at appropriate times of year is also important when it is not likely to washed off by rain into water ways Fertilisers should not be sprayed around streams rivers and lakes so that they do not become contaminated.