This year’s dead zone in the Gulf of Mexico, usually around 6,000 to 7,000 square miles, might well be the largest in history. The culprit? Heavy rains and flooding in the Midwest. All that runoff from the breadbasket will make its way downstream carrying copious amounts of agricultural fertilizer runoff into the Gulf. Time magazine has the story.
The Gulf dead zone, second largest in the world, is composed of oxygen-depleted water that does not support life. The process by which it forms is known as “hypoxia.” Basically, the process starts with nitrogen and phosphorous- based fertilizers being swept in quantity through the Mississippi River basin and into the Gulf at the Louisiana Delta. The fertilizer fuels the growth of algae which eventually dies or is eaten by zooplankton. Bacteria feed on the mass of dead algae and the zooplankton’s feces, exhausting the water’s oxygen as they do. (more…)