Methane and carbon dioxide fluxes at the sediment-water interface in organic-rich reservoirs, Federal State of Micronesia

Abstract

The organic contents are recorded in mangrove swamps and sandy sediment as 10.5-34.3 mg g-1, 0.3- 1.1 mg g-1, respectively. In the incubation chamber, the oxygen consumption rate is larger in organic-rich mangrove sediments (7.6 ± 0.3 to 13 ± 0.6 mmol O2 m-2 d-1) than in the sandy sediment (2.3 ± 0.2 mmol O2 m-2 d-1). The diffusive flux of methane and carbon dioxide from sediments to the overlying water are 0.5-10 μmol CH4 m-2 d-1, 32.4 - 82.1 mmol CO2 m-2 d-1, respectively.Mangrove swamps as a sink of organic matters transform the large amounts of carbon delivered from terrestrial and marine ecosystem. As a consequence of anoxic- or suboxic degradation of carbon in the sediment and the water column, carbon dioxide and methane are emitted into the atmosphere.3 ± 0.6 mmol O2 m-2 d-1) than in the sandy sediment (2.3 ± 0.2 mmol O2 m-2 d-1). The diffusive flux of methane and carbon dioxide from sediments to the overlying water are 0.5-10 μmol CH4 m-2 d-1, 32.4 - 82.1 mmol CO2 m-2 d-1, respectively.Mangrove swamps as a sink of organic matters transform the large amounts of carbon delivered from terrestrial and marine ecosystem. As a consequence of anoxic- or suboxic degradation of carbon in the sediment and the water column, carbon dioxide and methane are emitted into the atmosphere.