Methane release from Gulf coast wetlands

A seasonal study of methane release from adjoining salt, brackish and fresh marsh sediment and the adjacent open water areas in Louisiana’s Barataria Basin indicates that methane emission isa significant process in the carbon and energy flow of the ecosystem. Methane emission was inversely related to salinity and sulfate concentration, with methane increasing and salinity and sulfate decreasing with increasing distance from the coast. The annual amounts of methane evolved were 4.3, 73 and 160 g C m^-2 for the salt, brackish and fresh marshes, respectively. In vitro experiments show that methane production is sensitive to the addition of sulfate, high concentrations (10 mM SO₄) inhibiting methane evolution.