Sea Ice Biogeochemistry

 

Figure 1. Ikaite crystals

Klaus Meiners, Gerhard Dieckmann, Ellen Damm, and Daiki Nomura

Researchers from Germany and Japan will focus on the gas content and gas fluxes of the sea ice, and will also study the sea ice carbonate chemistry and its calcium carbonate content. Calcium carbonate can precipitate in cold and saturated sea ice brines resulting in the formation of ikaite crystals. These crystals, which were only recently discovered in natural sea ice have a salt-like appearance (Fig. 1) It is assumed that calcium carbonate formation in sea ice may be important component in the sea ice-driven carbon pump in ice-covered oceanic waters.

Dr. Gerhard Dieckmann, a sea ice ecologist and biogeochemist from the Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven will sample sea ice and snow to establish the occurrence and patterns of ikaite distribution and to determine the exact environmental conditions, which induce CaCO3 precipitation so as to assess the significance of this process in the polar carbon cycle.

Dr. Ellen Damm, a biogeochemist also from the Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven, plans to make an extensive characterisation of the spatial variability of the climate-cooling gas  dimethylsulfide (DMS), its sea ice precursor dimethylsulfoniopropionate (DMSP), methane (CH4), and delta13C-CH4 which are both produced and experienced by sea ice communities.

Ellen will sample sea ice by taking cores with a standard corer, brines from sackholes and under ice sea water. Sea ice cores will be sectioned and melted at 4°C. Methane concentration will be measured on board by gas chromatography equipped with a flame ionization detector (FID) and DMS as well as DMSP by a pulsed flame photometer (PFPD). Gas samples will be stored for analyses of the delta13C values of methane. These measurement will be carried out by mass spectrometry in the home laboratory in Germany.

Dr. Daiki Nomura, a Japanese postdoctoral researcher at the Norwegian Polar Institute will characterize carbon dioxide (CO2), CH4, and volatile organic compounds (VOC) concentrations in and over the sea ice in the East Antarctica. Daiki’s work aims to measure gas fluxes across the sea ice – snow – atmosphere interfaces, and additionally includes the collection of samples to quantify the carbonate system and other biogeochemical properties in both the sea ice and the under-ice water column. These biogeochemical components will be collected from snow, sea ice, brine and under-ice water. Measurements will be taken both in-situ and from melted ice cores.

Dr. Ellen Damm (ellen.damm@awi.de)

Dr. Gerhard Dieckmann (gerhard.dieckmann@awi.de)

Daiki Nomura  (daiki.nomura@npolar.no.)