Friday, September 23, 2011Good morning,
Part of what it means to be environmentally minded is knowing what the important environmental issues of the day are. For example; did you know that one of the largest dead zones in the world is right in our own Mississippi River Basin in the Gulf of Mexico?
The same Gulf of Mexico that supplies 72 percent of U.S. harvested shrimp, 66 percent of harvested oysters, and 16 percent of commercial fish.
But what is a dead zone? Scroll down for more.
Thanks for reading,
Your Living Green editor
Email the Editor***The dead zone is caused by nutrient enrichment from the Mississippi River, particularly nitrogen and phosphorous. Watersheds within the Mississippi River Basin drain much of the United States, from Montana to Pennsylvania and extending southward along the Mississippi River.
Most of the nitrogen input comes from major farming states in the Mississippi River Valley, including Minnesota, Iowa, Illinois, Wisconsin, Missouri, Tennessee, Arkansas, Mississippi, and Louisiana. Nitrogen and phosphorous enter the river through upstream runoff of fertilizers, soil erosion, animal wastes, and sewage.
In a natural system, these nutrients aren't significant factors in algae growth because they are depleted in the soil by plants. However, with anthropogenically increased nitrogen and phosphorus input, algae growth is no longer limited. Consequently, algal blooms develop, the food chain is altered, and dissolved oxygen in the area is depleted.