Dead zones in coastal oceans have been spreading since the 1970s, now taking up an area of about 245

Dead zones in the coastal oceans have spread exponentially since the 1960s and have serious consequences for ecosystem functioning. The formation of dead zones has been exacerbated by the increase in primary production and consequent worldwide coastal eutrophication fueled by riverine runoff of fertilizers and the burning of fossil fuels. Enhanced primary production results in an accumulation of particulate organic matter, which encourages microbial activity and the consumption of dissolved oxygen in bottom waters. Dead zones have now been reported from more than 400 systems, affecting a total area of more than 245,000 square kilometers, and are probably a key stressor on marine ecosystems.

Science. Spreading dead zones and consequences for marine ecosystems. Diaz RJ, Rosenberg R., 2008 Aug 15;321(5891):926-9. doi: 10.1126/science.1156401. Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA. [verified 4/15/14]

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