Researchers from Ohio State University and Louisiana State University are collaborating to design what could become the most ambitious ecological restoration effort ever: returning wetlands to the Midwest. This, they say, would help to solve ecological problems in both southern and northern states.
Every year, from late spring through early fall, a "dead zone" blooms in the Gulf of Mexico. The dead zone is a region of water in the gulf with extremely low oxygen levels, roughly the size of the state of Massachusetts.
It is caused by blooms of algae, which are fed by nitrogen in fertilizer runoff from agricultural lands in the Midwest. The nitrogen is transported by rainwater into streams and rivers which flow into the Mississippi river - the Mississippi then carries the nitrogen to the gulf.
The "dead zone" is so called because when the algae die; they sink through the water to the bottom and decompose, using up nearly all of the oxygen in the water in the process. That makes it difficult for other aquatic species to survive.
The problem, says William Mitch, a professor of natural resources and environmental science at OSU, is that the nutrient-rich water has been flowing from farmlands directly into the Mississippi. It didn't used to be that way.
Mitch is collaborating with John Day, of the department of oceanography and coastal studies at Louisiana State University, and with other Midwestern researchers to design a natural treatment system for the runoff - namely, to restore wetlands to the Mississippi watershed.
Wetland restoration would provide a buffer zone between farmlands and rivers to remove nitrogen in runoff.
The researchers say the restoration effort should include both wetlands and forests along river floodplains. While the wetlands would remove most of the nitrogen in the runoff, day notes, the floodplains would serve as a second line of defense.
While it is clear the source of the nitrogen is agricultural runoff, Day adds, the purpose of the study is not to target farms. He says wetlands restoration could solve an environmental problem without impinging on agricultural production.
Such a basin-wide ecological restoration won't come cheap. Mitsch says it could cost about 80 million dollars, roughly ten times the cost of the ongoing everglades restoration, currently the largest environmental restoration effort in the world. Once funded, he adds, the research agenda alone could take a decade. The actual restoration could take much longer - perhaps as much as a century.