Ocean Dead Zones June 2015 | Page 5

5

The primary human-related factor in the formation of ocean dead zones is agriculture. According to Seaweb 2014, is estimated that about 1.6 million metric tons of nitrogen-primarily from the highly fertilized agricultural regions of Southern Minnesota, Iowa, Illinois, Indiana, and Ohio- enters the Gulf annually from the Mississippi Basin. Three times the amount of nitrate has been discharged since 1970(Seaweb, 2014). Also, agriculture accounts for 65% of the nitrogen flux to the Gulf; soil erosion, groundwater discharge, and atmospheric deposition are estimated at 24%, while municipal and industrial point sources contribute about 11%(Seaweb, 2014). According to J. Silverman in 1998, recent analyses consider that a 50% reduction of nitrogen loading to the Gulf is possible if a variety of efforts are implemented.

Reversing dead zones is going to take a lot of time and effort and won’t come easy. Scientists will need to monitor and protect the oceans levels. Nitrogen is a big concern not just in the oceans, but globally and will need to also be monitered by scientists. Effects worldwide include threats to human health in the form of high nitrate levels in drinking water, losses of important trace nutrients in soil, the formation of acid rain and photochemical smog, and a variety of impacts in coastal waters including increases in harmful algal blooms and declines in commercial fisheries(1998, Silverman). In addition, nitrogen in the form of nitrous oxide is a contributor to the 'greenhouse effect' as associated with climate change(1998, Silverman).

HUMAN IMPACT