Eutrophication Overview - Results of Excessive Nitrogen & Phosphorous Runoff (PHOTOS)

Special thanks to Lisa Dirks for contributing this blog post.  Lisa is The GreenHarvest Group's Research Manager. She holds a BS in Biology and MS in Sustainability from Arizona State University.

Eutrophication occurs when bodies of water are polluted by high concentrations of nutrients, especially phosphates and nitrates. These nutrients can reach water naturally through the surrounding vegetation and landscape, but more commonly it’s through human activity (cultural eutrophication from fertilizer runoff and sewage discharge) and is a particular problem in slow moving rivers and shallow lakes. Additionally, through continuous increase in sediment deposition the lake or river bed can rise, resulting in invasive plants colonizing the water body and eventual conversion to dry land.

Excessive nutrients in water bodies cause exponential growth of algae.  High levels of organic matter combined with decomposing algae rob the water of available oxygen, resulting in broad "dead zones" such as those often documented in the Gulf of Mexico and the Chesapeake Bay. Furthermore, some types of algae, like red tide, produce a deadly neurotoxin hazardous or even fatal to both marine life and humans. As a result, eutrophication destroys fisheries, habitats, ecosystems, and causes the death of marine life living in or dependent on this body of water.

Dead zone in the Sassafrass River, a tributary of the Chesapeake Bay. Source: http://www.dnr.state.md.us/mydnr/askanexpert/algae_blooms.asp

Besides eutrophication, excessive nitrogen run-off results in nitrate pollution in ground water and private wells sickening all who drink it, including humans. Nitrates can reduce the bloods ability to carry oxygen. This pollution can make water too contaminated to drink for decades.  

These issues can be controlled. Mitigation is possible through waste water treatment; eliminating detergents that contain phosphorous; reducing nitrogen/phosphorous fertilizer use; controlling agriculture runoff; and reducing the use of phosphorus in animal feed (resulting in less P in manure).

Compared to conventional fertilizers, GreenHarvest achieves the same crop yields using a fraction of the nitrogen and no additional phosphorous. Additionally, GreenHarvest’s sustained release of nutrients, and other molecular properties, result in reduced leaching and runoff of nutrients into the water table.  Thus, use of GreenHarvest can help eliminate the issues associated with excessive phosphorus and nitrogen use in agriculture, without sacrificing crop yields.

Eutrophication photos below:

Eutrophication along the Florida coastline. Source: Marietta College http://www.marietta.edu/~biol/biomes/mangroves.htm

Results of algae blooms and phytoplankton "Red Tide." Source: SAAW International http://www.saawinternational.org/enviromentandhealth.htm

Algal bloom in Matilda Bay, Australia. Photo by Dennis Sarson (University of Western Australia). Source: www.ozcoasts.org.au