Eutrophication exam question Flashcards
what is eutrophication
the artificial enrichment of aquatic habitats by excess nutrients often caused by runoff of fertilisers
What are the problems caused by excess nitrate in soils
agricultural land the increased use of fertiliser has reduced species diversity on grassland
fertilisers increase the growth of grasses and plants such as nettles which shade out smaller plants
problems caused by excess nitrates leaching into rivers
the leaching of nitrate and phosphates from the surrounding land is a slow natural process during which the concentration of salts builds up in bodies of water
in lakes and rivers, the mineral ions normally accumulate until equilibrium is reacher and their addition to the water is exactly counterbalanced by the rate at which they are removed
sewage and fertilisers are an additional source of tese minerals and their leaching from the land into the water may result in eutrophication
what is the impact of eutrophication
nitrate = fertiliser
algae bloom
water becomes green and light is unable to penetrate to any depth
plant in the deeper regions of the lake cant photosynthesise and they die
a general decrease in animal species diversity as they rely on plants for food and shelter
short-lived algae soon die and are decomposed by saprobiontic fungi
Water in all but the very upper layers which are exposed to the air becomes deoxygenated
anaerobic bacteria in the water reduce nitrate to nitrite .
how can these issues be avoided
restrict the amount of fertiliser applied to the soil
only apply fertiliser at a time when the crops are actively growing so that is readily used and does not remain in the soil to be leached away
leave a strip at least 10 metres wide next to watercourses
dig drainage ditches
