Eutrophication is when a lake or pond becomes excessively enriched with nutrients. It is a natural process that usually occurs over a long period of time without human interference. However the process can accelerate very quickly, for example, due to nutrients leaking into a lake from a man-made source.
The excess nutrients can cause algal blooms and can use up the oxygen in the water, resulting in the death of many aquatic organisms such as fish. Algae can even produce toxins that are harmful to higher forms of life.
Waters suffering from eutrophication will often undergo a change in the species present. This often means a lack of biodiversity and a reduction in the number of different species overall. For example, once a lake is affected, shoals of larger roach which may have always been present can sometimes ‘disappear’ and not return. Some species of plant may also disappear which can have a negative effect on the small creatures that live in them.
Numerous lakes are already affected by eutrophication, including some of the most iconic waters in the country, and even the world. With Lake Erie (USA) and Lake Victoria (Africa) both being affected, to name but two.
However many angling clubs are unaware they have a problem, often until it is too late. Natural England highlighted that over 80% of SSSI sites tested, suffered adversely from eutrophication, this is mentioned in the following publication.