is the natural ageing process of a lake caused due to nutrient enrichment. It is
brought down by the runoff of nutrients such as animal wastes, fertilizers, and
sewage from land which leads to an increased fertility of the lake. As a result,
it causes a tremendous increase in the primary productivity of the ecosystem.
This leads to an increased growth of algae, resulting into algal blooms. Later,
the decomposition of these algae depletes the supply of oxygen, leading to the
death of other aquatic animal life.