Many of Louisiana’s coastal wetlands depend upon the annual cycle of birth and death of plant material to help build up soil height as a way of trying to stay ahead of relative sea level rise caused by the combination of sinking land and rising waters.
A new paper published in “Wetlands,” shows that although researchers found relatively little difference in the rates of this short-term accumulation across marsh types, as salinity in wetlands rises, the amount of organic carbon in soil that can accumulate as a buffer against relative sea level rise decreases.
That also means freshening of certain wetlands with coastal restoration project such as sediment diversions being planned for the Mississippi River or even additional rainfall, can help wetlands regain some of this organic storage ability and perhaps give these areas a buffer against succumbing as quickly to higher water levels.
“Evaluating all marsh types, from fresh to saline, for these kinds of impacts is essential to understanding how Louisiana’s marshes respond to changing conditions,” said Melissa Baustian Ph.D., researcher with The Water Institute of the Gulf and lead author of the article.
Other authors of the report include researchers from the U.S. Geological Survey, Gulf South Research Corporation, Coalition to Restore Coastal Louisiana and the Department of Earth & Environmental Sciences at Tulane University.