Distribution of total inorganic carbon (TCO2) in µmol/kg in the Weddell Gyre along the Prime Meridian (above) and 20°E (below) (from Bakker, Hoppema et al, 2008) (Photo: Alfred-Wegener-Institut)

Carbon and transient tracers dynamics: A bi-polar view on Southern Ocean eddies and the changing Arctic Ocean. The oceans and the climate system appear to be changing in many different aspects. The rapidly retreating summer sea ice cover in the Arctic and the increasing westerlies in the Southern Ocean are recent exponents of this phenomenon. Both may have consequences for the uptake of CO2 by the polar oceans.

In the Southern Ocean, a decrease of the CO2 sink was suggested due to enhanced upwelling of deep waters. Northward eddy transport across the Antarctic Circumpolar Current may or may not be counteracting this. We propose to investigate the carbon budget of eddies and the role of eddies in the equatorward transport of carbon. CO2 measurements within and across different eddies will be conducted, as well as transient tracers, which will be utilized to describe the physical characteristics of the eddies, and to calculate anthropogenic CO2. In the Arctic Ocean, we want to investigate the physical and biogeochemical components of the Arctic Ocean carbon system and its feedbacks to the environment, as well as to explore how the Arctic Ocean contributes to the ventilation of the global oceans, including recent changes. Measurements of CFC-12 and SF6 will be conducted. With these transient tracers and combined with previous data, anthropogenic CO2 in the Arctic Ocean will be determined. Also the relation of advection to mixing will be better constrained with this combination of two tracers, enhancing the knowledge of circulation within the Arctic.

This project is a cooperation with the Helmholtz-Zentrum für Ozeanforschung Kiel