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 mmol×m^-2×d^-1 for CH₄ and from -1.27 to 47.02 mmol×m^-2×d^-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.