What’s eutrophication and what causes it?
Another name for it Alagae bloom, Fertilisers (NPK) enters a body of water increasing nutrients in the water that Algae can take in, causing the amount/population of algae to increase, this has many adverse affects on the aquatic population and humans.
Such as -
high population of algae will cause more decomposition when they die taking away O2 from the water.
Effect drinking water supply for humans - toxic.
Eutrophication is caused by an influx of limiting nutrients, such as phosphorus or nitrogen, which causes the short term rapid growth of algae. However, as this was a sudden influx, the increase in algae is unsustainable, and many die off. This causes many dead organisms in the water, and the BOD (Biochemical oxygen demand) increases, leading to a dead zone where many other organisms die off.
Fertilizer (and other N and P containing compounds) that contains nitrogen or phosphorus, limiting factors in the environment, runs off into bodies of water and results in an algal bloom. When the algae dies, microbes digest the algae and the oxygen in the water which leads to a decrease in the dissolved oxygen levels in the water and death/loss of biodiversity.