Lake eutrophication
The accumulation of nutrients (such as phosphorus or nitrogen) in the water of a lake can lead to a change of state that results in the proliferation of algae, the degradation of water quality and biodiversity, and possibly bacterial blooms: this is eutrophication. The problem of the lake and its riparian holdings is to determine whether it is possible to reconcile the practice of an activity which provides nutrients and the conservation of the lake in a desirable state (oligotrophic, as opposed to eutrophic).
This problem is described in detail in: