National Centre for Antarctic and Ocean Research (NCAOR),GOA

Paleoclimate Air-Sea gas exchange of CO2 and impacts on Biota

Air-Sea gas exchange of CO2 and impacts on Biota

The atmospheric CO2 content increases steadily due to human activities; the ocean is affected by this and follows the increase. The driving force that leads to a source/sink pattern within the ocean is the concentration gradient between atmospheric and oceanic pCO2. The distribution of the surface pCO2 in the ocean is much less homogenous than in the atmosphere as it regulated by the biological, physical and chemical reactions. With the onset of the industrial revolution the atmospheric pCO2 of 280 ppm has increased to a recent value of 390 ppm in more than a century. The implication for the oceanic pCO2 is significant. The regional variability of the seawater pCO2 is considerable. Physical processes, thermo dynamical and biological processes affect the carbonate system. The air-sea gas exchange of CO2 plays an important role for the carbon chemistry in surface waters.

Carbon dioxide chemistry in seawater


Based on the record of the past there is little doubt that global warming and rise in CO2 will result in different distributions of marine planktonic organisms in near future. If the ocean warming were to be simply and positively correlated with latitude the expansion of habitat in a poleward direction would continue. But since the rate of change is expected to be very rapid, questions immediately arise regarding the potential of the biota to accommodate to these rates of change. The most affected would be the calcareous organisms as a result of the slowly acidifying sea. In recognition of the need for basic research concerning the nature, extent and impact of ocean acidification on oceanic environments in the past, present and future, we attempt to understand the chemistry of ocean acidification and, in particular, its interplay with fundamental processes of organisms. Also we are attempting to understand how ocean acidification interacts with processes at the organism level and how such interactions impact the structure and function of ecosystems, e.g. through biogeochemical cycling, food webs and other interactions and how oceans have responded in past to the acidification.