Organic sulphur compounds in sea ice and seawater in the central Arctic Ocean

• Main Authors: Uhlig, Christiane, Vinogradova, Elena L., Peeken, Ilka, Damm, Ellen
• Format: Conference Object
• Language: unknown
• Published: 2018
• Subjects: Arctic; Arctic Ocean; Sea ice
• Online Access: https://epic.awi.de/id/eprint/47010/; https://hdl.handle.net/10013/epic.a8c34af3-9a1f-4a45-b3e1-73dbea9a5e47

Dimethylsulfide (DMS) is a semi-volatile sulfur component and under discussion to be climate active, as its oxidation products might act as cloud condensation nuclei - thus cooling the atmosphere. DMS and its precursor dimethylsulfoniopropionate (DMSP) are frequently found in high concentrations in sea ice, since the unique and extreme physico-chemical conditions favour the production of both compounds by sea ice microalgae. Both compounds are cycled between the ice and underlying water column during melting and freezing processes and eventually DMS is released to the atmosphere. Data on DMS and DMSP in the high latitudes and particularly Arctic are scarce up to date. Our study presents profiles of DMS and DMSP in sea ice cores and the underlying water column collected during the Transarc II cruise on RV Polarstern in the central Arctic Ocean in late summer 2015. DMSP concentrations in sea ice with up to 200 nmol/L were often 10 to 100 times higher than typical seawater concentrations. In the underlying seawater higher DMSP concentrations were found in lower saline water, indicating DMSP release during melting in late summer. DMS concentrations in the ice were 2-3 times higher than typically found in open water. Sea ice profiles of DMS followed DMSP concentrations, but show indication of release of DMS to the underlying water column. The generally low DMS concentrations in the water indicate either rapid microbial cycling or exchange of this volatile compound to the atmosphere, e.g. through leads in the ice cover.