Eutrophic: Lakes that are eutrophic in nature have high levels of biological productivity. An abundance of plants is supported by such lakes due to the rich nutrient constitution, especially nitrogen and phosphorus. Initially, eutrophic lakes accelerate multiplication and growth of lake fauna due to the high levels of oxygen provided by a large number of plants growing in the lake. However, when things cross limits and plants or algal blooms overcrowd the lake, the lake fauna suffers due to the high levels of respiration by the living vegetative matter. Eutrophication might occur naturally or due to human impact on the environment.