Variability of carbon dioxide production rates in the water masses of Southern Adriatic Pit in the period 1993-2004

During the last century, the global increase in fossil fuels consumption together with the reduced capacity to remove CO2 due to deforestation, have caused a dramatic input of carbon dioxide into the atmosphere. The resulting enhancement of the natural Greenhouse Effect is partially balanced by sequestration of CO2 in the deep oceanic waters. In fact, topical studies have supported the significant role of the oceanic biological pump with respect to atmospheric CO2 build-up. In the marine ecosystem the biological pump controls the export of biogenic carbon from the surface layers down to the deep. In brief, this mechanism transforms in the euphotic zone, through photosynthesis processes, carbon dioxide into organic matter; the latter sinks to the waters below and at the same time is consumed by respiration with the production of metabolic CO2. However, during the formation of dense waters, a significant quantity of organic products is conveyed from the surface within the water mass and remineralized inside it, thereby altering the normal flow of the biological pump. In this study the evolution of carbon dioxide production rates (ETS activity) in a deep convection site of Eastern Mediterranean Sea (the Southern Adriatic Pit) in the period from 1993 to 2014 is reported in relation to climatic change.