Carbon flow in coastal Louisiana

Abstract

Carbon flux data was synthesized to estimate carbon flow along a salinity gradient in Louisiana's Barataria Basin, a major Gulf Coast estuary (USA). Using a mass balance approach, we found an estuarine carbon surplus of 150 to 250 g yr-l, which originated primar~ly in the tidal salt marsh. Carbon export from marshes to adjacent water bodies decreases with distance from the Gulf of Mexico. The Barataria Basin marshes function as important global carbon sinks within this export gradient. High community respiration, methane emission, and carbon accretion resulting from annual carbon fixation reduce carbon 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 carbon.