Gulf “Dead Zone” Could be Biggest on Record!
The Mississippi River flows down through the Louisiana delta into the Gulf of Mexico. On its way it passes through prime farmlands where it receives run-off of excess nutrients (nitrates, phosphates etc …) from fertilizers that are applied to increase crop yields. This nutrient-rich water enters the Gulf of Mexico and causes an “bloom” of algae – a sudden dramatic increase in the amount of green algae in the water. As these algae die, bacteria populations then sky-rocket in order to decompose the dead cells. Since bacteria need oxygen, the extraordinary increase in bacteria populations causes the oxygen levels to fall drastically, killing other organisms that require the oxygen. This drop in oxygen levels creates a “dead zone” (hypoxic zone) in the Gulf … a zone where living organisms (zooplankton, fish, shrimp, crabs, etc …) cannot survive. Because fertilizer use spikes in late spring and early summer, the dead zone is at its height in the summer months. Studies show that this summer’s dead zone could be the largest ever recorded – 17 to 21% larger than ever before!
The fancy term for too much nutrients in a body of water is “eutrophication” … and the problem is not unique to the Gulf of Mexico. The same issue affects Lake Winnipeg. The graphic below shows the many sources of nitrogen in Lake Winnipeg. One major source is the many rivers that flow through agricultural regions. Factory farming is also a big culprit. Hog barns in Manitoba have thousands of hogs confined in large confined spaces. The waste from these animals is collected in “lagoons” – cess-pools that are full of nitrates. Heavy rainfalls can cause some of this waste and/or applied fertilizer to wash directly into rivers that eventually make their way to Lake Winnipeg. The City of Winnipeg also treats its water with phosphates … and people apply fertilizers to their lawns and use phosphate-containing dish soaps and dishwasher detergents. All of these nutrients make their way into Lake Winnipeg where huge algae blooms appear each summer … especially in the North basin.
Should the province regulate the use of fertilizers among urban users? What about improving regulations on farmers for the use of fertilizers?? Should there be more large hog barns in Manitoba? What is their environmental record with respect to spills and the disposal of their animal wastes?
Mr. Patenaude