Partial pressure and air-sea CO2 flux in the Aegean Sea during February 2006

Data on the distribution of fCO(2) were obtained during a cruise in the Aegean Sea during February 2006. The fCO(2) of surface water (fCO(2)(sw)) was lower than the atmospheric fCO(2) (fCO(2)(atm)) throughout the area surveyed and Delta fCO(2) values varied from -34 to -61 mu atm. The observed under-saturation suggests that surface waters in the Aegean represent a sink for atmospheric CO2 during the winter of 2006. Higher fCO(2)(sw) values were recorded in the 'less warm' and 'less saline' shallow northernmost part of the Aegean Sea implying that the lower seawater temperature and salinity in this area play a crucial role in the spatial distribution of fCO(2)(sw). A first estimate of the magnitude of the air-sea CO2 exchange and the potential role of the Aegean Sea in the transfer of atmospheric CO2 was also obtained. The air-sea CO2 fluxes calculated using different gas transfer formulations showed that during February 2006, the Aegean Sea absorbs atmospheric CO2 at a rate ranging from -6.2 to -11.8 mmol m(-2) d(-1) with the shipboard recorded wind speeds and at almost half rate (-3.5 to -5.5 mmol m(-2) d(-1)) with the monthly mean model-derived wind speed. Compared to recent observations from other temperate continental shelves during winter period, the Aegean Sea acts as a moderate to rather strong sink for atmospheric CO2. Further investigations, including intensive spatial and temporal high-resolution observations, are necessary to elucidate the role of the Aegean Sea in the process of transfer of atmospheric CO2 into the deep horizons of the Eastern Mediterranean. (C) 2009 Elsevier Ltd. All rights reserved.