Carbon flow in coastal Louisiana

Abstract
C flux data was synthesized to estimate C flow along a salinity gradient in Louisiana''s Barataria Basin, a major Gulf Coast estuary (USA). Using a mass balance approach, an estuarine C surplus of 150-250 g m-2 yr-1 was found, which originated primarily in the tidal salt marsh. C export from marshes to adjacent water bodies decreases with distance from the Gulf of Mexico. The Barataria Basin marshes function as important global C sinks within this export gradient. High community respiration, methane emission and C accretion resulting from annual C fixation reduce C export from the northern part of the basin. Higher primary production, low community respiration and low methane evolution make the southern part of the basin a source of aquatic C.