Ιnsights into the Nutrients and Carbon Pools and Dynamics in the Aegean Sea

The concentrations and distribution of nutrients and carbon in the Aegean Sea are strongly influenced by the biogeochemical processes, the complex hydrological and circulation characteristics, as well as by the geographic setting and bottom topography of its sub-basins. Historical data have shown that the distribution of oxygen and nutrients in the water column of the South Aegean Sea was severely affected by the major Eastern Mediterranean Transient (EMT) event. The “nutrient rich-oxygen poor” layer that was established during the EMT in the South Aegean Sea altering the characteristics of this basin, was till recently present in greater depths than previously, though with faded hydrochemical properties. The temporal evolution of the dissolved oxygen concentrations for the period 1997–2011 in the laterally isolated deep layers of the depressions of the North Aegean Sea, revealed long periods of stagnation interrupted by weak dense-water formation events. The signature of these events was also depicted in the synoptic view of the concentrations of dissolved organic carbon, nitrogen, and phosphorus, as well as of the total dissolved inorganic carbon and total alkalinity. In addition, considerable differences of the dissolved organic matter and carbonate system parameters between the North and the South Aegean Sea attributed to the influence of the Black Sea inputs were detected.