Eutrophication: causes, effects, and environmental management

Eutrophication is the process by which human activities, as a result of released nitrogen and phosphorus, drives excessive plant and algae growth within bodies of water (Carpenter, 2009; James E. Cloern & J. Emmett Duffy, 2007). This artificial enrichment causes abnormally high rates of growth, often known as algal blooms, and can function to eventually degrade water quality (James E. Cloern & J. Emmett Duffy, 2007). The increased nitrogen and phosphorus within these bodies of water can often be traced to fertilizer run-off of farms and lawns or sewage-treatment plants. Extreme algal growth can result in anoxic conditions due to high levels of oxygen utilization, potentially killing many marine creatures and fish (James E. Cloern & J. Emmett Duffy, 2007). The Salton Sea in California, the Baltic Sea, the Sea of Marmara near Turkey, and Lake Prespa on the boundary of Macedonia and Greece are well-known examples of bodies of water which are or haven been undergoing eutrophication (James E. Cloern & J. Emmett Duffy, 2007).

Most solutions which have been proposed to deal with the problem of eutrophication target the source of the nitrogen and phosphorus (James E. Cloern & J. Emmett Duffy, 2007). Reduced livestock, reduced fertilizer usage, improved efficiency of fertilizer usage, reduced nitrogen emissions from industrial plants, and effective treatment of potential runoff and wastewater have all been suggested as methods to deal with eutrophication (Carpenter, 2009; James E. Cloern & J. Emmett Duffy, 2007). Additional suggestions include restoring buffer zones between potential sources of nutrient rich-runoff and susceptible bodies of water. The United States and Europe have each undertaken efforts to mitigate eutrophication by recommending a National Coastal Nutrient Management Strategy (via the 2000 National Research Council report) and establishing the European Union's Water Framework Directive, respectively (James E. Cloern & J. Emmett Duffy, 2007). Due to the diversity of sources for eutrophication, a concerted and multifaceted approach toward this problem will ultimately be required.