Dead zone in Gulf of Mexico twice as large as in 2012
Deanna Conners
Large dead zone in 2013 is partly due to wet spring conditions in the Mississippi watershed, which increased nutrient runoff, triggering algae blooms.
The oxygen-depleted dead zone that forms each summer in the Gulf of Mexico has reached 5,840 square miles in size, according to NOAA-supported scientists. The 2013 dead zone is about twice as large as the one that formed in 2012. The larger size of the dead zone in 2013 is partly due to wet spring conditions in the Mississippi watershed, which have increased the amount of nutrient runoff in contrast to last year, when drought gripped much of the region.
Nutrient runoff from agricultural fields and other human activities is transported down the Mississippi watershed into the Gulf of Mexico where it triggers algae blooms. When the algae die and decompose, the decomposition process uses up oxygen in the water. Low oxygen or hypoxia can be deadly to many types of marine organisms, especially those that can’t escape quickly.
Mouth of the Mississippi River photographed on November 27, 1999 with NASA’s Landsat 7 satellite. Image Credit: NASA.
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http://earthsky.org/earth/dead-zone-in-gulf-of-mexico-twice-as-large-as-in-2012?