This means that more nitrogen fertilizer is running off farmland directly into the river and into the Gulf of Mexico. Excess nutrients lead to increased algal production and increased availability of organic carbon within an ecosystem, a process known as eutrophication. When these algae die and organic material accumulates, the metabolism of the decomposer organisms uses all the oxygen stored in the water. Most aquatic species cannot survive at such low oxygen levels. The hypoxic zone forms in the middle of the most important commercial and recreational fisheries in the coterminous United States and could threaten the economy of this region of the Gulf.
Wetlands are among the most biologically productive natural ecosystems in the world.
The microbes, plants, and wildlife residing in wetlands are part of global cycles for water, nitrogen, and sulfur. In addition, wetlands store carbon within their plant communities and soil instead of releasing it to the atmosphere as carbon dioxide. They contribute to the stability of global levels of available and atmospheric nitrogen, atmospheric sulfur, carbon dioxide, and methane. Thus wetlands help to moderate global climate conditions and function in atmospheric maintenance. Wetlands can be compared to tropical rain forests and coral reefs in the diversity of species they support.