Study reveals potent carbon-storage potential of manmade wetlands

Terra Daily via SPX: After being drained by the millions of acres to make way for agriculture, wetlands are staging a small comeback these days on farms. Some farmers restore or construct wetlands alongside their fields to trap nitrogen and phosphorus runoff, and research shows these systems can also retain pesticides, antibiotics, and other agricultural pollutants.

Important as these storage functions of wetlands are, however, another critical one is being overlooked, says Bill Mitsch, director of the Everglades Wetland Research Park at Florida Gulf Coast University and an emeritus professor at Ohio State University: Wetlands also excel at pulling carbon dioxide out of the air and holding it long-term in soil.

Writing in the July-August issue of the Journal of Environmental Quality, Mitsch and co-author Blanca Bernal report that two 15-year-old constructed marshes in Ohio accumulated soil carbon at an average annual rate of 2150 pounds per acre-or just over one ton of carbon per acre per year.

The rate was 70% faster than a natural, "control" wetland in the area and 26% faster than the two were adding soil carbon five years ago. And by year 15, each wetland had a soil carbon pool of more than 30,000 pounds per acre, an amount equaling or exceeding the carbon stored by forests and farmlands....

Point Pelee marsh in Ontario, shot by Andrea, Wikimedia Commons via Flickr,  under the Creative Commons Attribution 2.0 Generic license