A satellite image shows the flood of sediment pouring out of the Mississippi River into the Gulf of Mexico (more than 500 million tons per year). The torrent of nutrients feeds blooms of marine plants, creating one of the ocean’s most biologically productive regions. But an overabundance of nutrients can sometimes cause microscopic plants and animals to grow, die, and decay so fast that they deplete the oxygen in the water. These “dead zones” (blackened waters in the image) can linger for months. (Liam Gumley, Univ. of Wisconsin-Madison, and the MODIS
science team.)[back]
|
