What is Eutrophication?? • Waterways are naturally low in nutrients, this limits the growth of water plants. • This is a process when a body of water such as a stream becomes over enriched in nutrients. • The nutrients are mainly nitrates and phosphates.
Causes of Eutrophication!! • Eutrophication is when fertilisers used by farmers leak into water courses, these fertilisers could be nitrogen based or things like slurry. • The fertilisers get into the water course due to runoff, the fertilisers is not absorbed by the soil and then drains off the field in rain water.
Effects of Eutrophication!! • As I said earlier water plants are limited by the amount of nutrients, a sudden enrichment of nutrients causes a increase in growth. • The greater biomass of plants increases competition, this will cause more plants to die. • This causes an increase in the number of bacteria which use the dead matter in respiration. • They also use oxygen which is dissolved in the water, in respiration.
Effects of Eutrophication!! • Sensitive animal species such as Trout and Mayfly nymphs are now unable to carry out gas exchange due to less oxygen being dissolved in the water. • This causes them to die, or they are out competed by animals which can extract oxygen from the water better. • The bacteria may also produce toxic by-products that will kill animals living in the water or those using it as drinking water.
Overcoming the Problem • Farmers need to take care with when they able fertilisers, for instance a good time is when its frosty. • Also using organic fertilisers is better • than inorganic, as they break done • and release the nutrients more slowly, • such as slurry. • Also Farmers can take care where they apply fertilisers, for instance not to close to a water course.