Carbon Dioxide Stimulates Marsh Elevation Gain, Helping Offset Flooding from Sea Level-Rise
Elevated concentrations of carbon dioxide may help some coastal marshes keep up with rising sea level by stimulating plant production and marsh building.
Coastal wetlands provide barriers to storm surges and flooding, provide valuable habitat for wildlife, and are important nursery grounds supporting commercial fisheries.
The U.S. Geological Survey conducted research that showed how marsh elevations might increase when exposed to higher concentrations of carbon dioxide.
"Coastal wetlands are threatened by sea-level rise, and this research allows for more accurate models to predict how much coastal submergence may occur," said USGS scientist Karen McKee. "This information will lead to a more complete picture of how carbon dioxide interacts with our Earth system, helping decision-makers plan for the future and protect these valuable resources."
Scientists also found that higher concentrations of carbon dioxide reduced the impacts of seawater on a dominant plant species in coastal marshes. Research was done by exposing marsh "mesocosms" (miniature marshes established in containers) to simulated sea-level rise. A field study also found that elevated carbon dioxide levels increased the rate of soil elevation gain in a marsh located in Chesapeake Bay.
Research was a collaborative effort with the Smithsonian Environmental Research Center and the University of Alabama.
Results of the USGS study are available online in the Journal of Ecology and in the Early Edition of the Proceedings of the National Academy of Sciences.