The influence of environmental factors on the carbon dioxide flux across the water–air interface of reservoirs in south-eastern Poland

Studies concerning the emission of carbon dioxide （CO2） were carried out in 2009-2012 for six reservoirs located in four provinces of south-eastern Poland. The CO2 flux across the water-air interface was measured using the ＂static chamber＂ method. The measured fluxes of CO2 （FCO2） ranged from -30.64 to 183.78 mmol/m2/day, and the average values varied in the range from -3.52 to 82.11 mmol/m2/day. In most of the cases, emission of CO2 to the atmosphere was observed. The obtained values of CO2 fluxes were comparable to values typical for other temperate reservoirs. Analysis of the influence of selected envi- ronmental factors on the FCO2 showed that it depends on parameters characterizing both the sediments and surface water. The CO2 flux at the water-air interface was positively correlated with parameters of bottom sediments such as porosity, content of organic carbon and total nitrogen; and negatively with pH value and 51℃ of organic carbon. In the case of the parameters characterizing surface water, positive dependences on the concen- trations of nitrate and total nitrogen, and negative relationships with water temperature and chlorophyll a concentrations, were found.