Dead Zones Starving World's Seas

The United Nations Environmental Program says there are now 146 dead zones worldwide, mainly around the coastlines of wealthy countries. Klaus Topfer, the Executive Director of the program says "[they're] gigantic and they're triggering alarm. Sometimes, their affects on the seas are irreversible."



World fertilizer use has soared tenfold over the last fifty years, which mirror the increase of dead zones. The dead zone in the Gulf of Mexico can cover 7,000 square miles, and is a bi-product of fertilizers flowing down the Mississippi River into the Gulf. Big farming states like Ohio, Indiana, Illinois, and Iowa drain 80 percent of their fertilizers into the Mississippi.



The world's largest dead zone is in the Baltic, where sewage and nitrogen fallout from burning fossil fuels combined with fertilizers have over-enriched the sea. The nutrients feed blooms of algae and phytoplankton. The algae drain the oxygen from the water, as do the decomposing bodies of plankton, when they fall to the seafloor and die.



Nearly a third of the dead zones are off the United States, including a notorious one in the Chesapeake Bay. However, these dead zone clusters can also be found around the coasts of Europe and Japan, and are now beginning to grow off of China, Brazil, Australia, and New Zealand.



Last year, the Louisiana dead zone was blamed for the tripling in shark attacks on Texas bathers. Fish and swimming crabs flee the pollution for cleaner waters, followed by the sharks.