Nonpoint source water pollution regulations in the United States The primary nutrients found in water due to nonpoint source pollution are nitrogen and phosphorus from fertilizers. An influx of these nutrients can lead to eutrophication within the water. This is when there is an excess of nutrients in water, thus leading to an explosion in the growth of algae. The algae can cover the lake and block sunlight from reaching the organisms below, typically killing them. NPS water pollution is regulated at the federal, state, and local level. Yet, the pollution persists and remains a significant problem. There are a number of reasons why current regulations have failed to
Eutrophication especially immobile bottom dwellers die off. In extreme cases, anaerobic conditions ensue, promoting growth of bacteria such as "Clostridium botulinum" that produces toxins deadly to birds and mammals. Zones where this occurs are known as dead zones. Eutrophication may cause competitive release by making abundant a normally limiting nutrient. This process causes shifts in the species composition of ecosystems. For instance, an increase in nitrogen might allow new, competitive species to invade and out-compete original inhabitant species. This has been shown to occur in New England salt marshes. In Europe and Asia, the common carp frequently lives in naturally Eutrophic