What is Eutrophication?
In the most basic terms, eutrophication is nutrient pollution. When a water-body receives too much of a particular nutrient phosphorous for most freshwater systems and nitrogen for saltwater the delicate ecological balance is disrupted. These nutrients fuel primary productivity, otherwise called plant growth, and tiny algae thrive. Algae grow incredibly fast and some species live less than a day. In mass, these plants shade the sunlight from reaching sea grasses rooted to the bottom thus limiting their ability to photosynthesize and threaten their survival. Sea grasses are a vital estuary habitat, serving as home to countless species of fish and shellfish, as well as providing food for birds and other creatures. When these algae live out their days and fall to the bottom of the water-body, a new cycle begins: decomposition.
Eutrophication is a condition stimulated by high nutrient condition that result in growth of phytoplankton. Although eutrophication is a normal process of lakes and estuaries, human activities accelerate the process at a much higher rate. Eutrophication is detrimental to the ecosystem of a water body as it blocks sunshine which results in the destruction of underwater flora. It also increases the oxygen take-up for the decomposition of algae, thus decreasing the amount of available oxygen vital for aquatic life.
Eutrophication is a natural lake aging process, which under normal conditions takes thousands of years to occur. It is the process by which lakes are enriched by nutrients (usually phosphorus and nitrogen) which leads to excessive plant growth. If phosphorus concentrations in a lake are greater than 20 micrograms per litre, the lake is nutrient enriched or eutrophic. Lakes that receive nutrients from human activities become “old” before their time. This accelerated aging is called cultural eutrophication. Sources of nutrients are municipal wastewater, faulty septic systems, lawn fertilizers, phosphorus rich detergents, and runoff from agricultural fields and construction sites.
