Skip to content

Simulated anthropogenic CO2 uptake and acidification of the Mediterranean Sea

May 6, 2014

MedSeA 150Constraints on the Mediterranean Sea’s uptake of anthropogenic CO2 are limited, coming only from data-based approaches that disagree by more than a factor of two. Here we simulate this marginal sea’s anthropogenic carbon uptake by applying a perturbation approach in a high-resolution regional model.

Our model simulates that between 1800 and 2001, basin-wide CO2uptake by the Mediterranean Sea has increased by 1.0 Pg C, a lower limit based on the corresponding model evaluation with CFC-12, indicating inadequate simulated deep-water ventilation. Furthermore, by testing a data-based approach (Transit Time Distribution) in our model, comparing simulated anthropogenic CO2 to values computed from simulated CFC-12 and physical variables, we conclude that the associated basin-wide uptake of 1.7 Pg, published previously, must be an upper bound. Out of the total simulated uptake of 1.0 Pg C, 75% comes from air–sea exchange into the Mediterranean Sea and 25% comes from net transport from the Atlantic across the Strait of Gibraltar. Sensitivity tests indicate that the Mediterranean Sea’s higher total alkalinity, relative to the global-ocean mean, enhances the Mediterranean’s total inventory of anthropogenic carbon by 10%. Yet the corresponding average anthropogenic change in surface pH does not differ significantly from the global-ocean average, despite higher total alkalinity. In Mediterranean deep waters, the pH change is estimated to be between −0.005 and −0.06 pH units.

Palmiéri J, Orr JC, Dutay J-C, Béranger K, Schneider A, Beuvier J, Somot S, 2014: Simulated anthropogenic CO2uptake and acidification of the Mediterranean Sea, Biogeosciences Discuss., 11, 6461-6517, doi:10.5194/bgd-11-6461-2014. Article.


Comments are closed.

%d bloggers like this: