Transport of organic carbon in the Atchafalaya Basin, Louisiana

Abstract

The Atchafalaya Basin comprises an 8 345 km2 lowland area within Louisiana. Annual organic carbon fluxes were determined for the 2 129 km2 Atchafalaya Basin Floodway (subject to frequent and prolonged natural flooding) and two subunits within the Floodway. Comparisons are made with an area not subject to extensive overflow due to its isolation from the Atchafalaya River by manmade levees. Comparisons are also made with some other areas reported in the literature. Overflow areas were found to have a large areal net export of dissolved organic carbon while the non-overflow area had a low net export. Areal export of particulate organic carbon was high in the non-overflow area while the overflow areas acted as sinks for particulate organic carbon. Prolonged overbank flooding, with the annual inundation of additional land areas and the decomposition of herbaceous materials and forest litter, renews the supply of organic carbon.