Diffusive Fluxes of CH4 and CO2 at the Sediment-Overlying Water Interface in Reservoir Ecosystems

The work detailed here concerned the CH4 and CO2 fluxes at the sediment-overlying water interface in Maziarnia and Nielisz Reservoirs, SE Poland. The research in question was conducted in the period of 2009-2011, the samples of sediment and overlying water were collected at two stations located in the upper and lower parts of each reservoir. The concentrations of CO2 and CH4 in pore water and overlying water were measured with the headspace method, using a Pye Unicam gas chromatograph (PU-4410/19) equipped with a methane analyzer allowing low CO2 concentrations to be detected. Diffusive fluxes of the analyzed gases at the sediment-overlying water interface were calculated on the basis of Fick's first law, and were found to range from -0.01 to 3.48 mmolxm(-2)xd(-1) for CH4 and from -1.27 to 47.02 mmolxm(-2)xd(-1) for CO2. Comparable fluxes elsewhere typify the reservoirs experiencing far-reaching eutrophication. No dependent relationships were found between the values calculated for fluxes and either season of the year or sediment characteristics.