| Summary: | Progress Code: completed Statement: Each eventual parameter important for global comprehension of the dataset is highlighted as comment, when needed, in the Final Sample List.xls file (See parent record). Overview of the project and objectives: To investigate whether nitrate uptake and processes other than nitrate uptake by phytoplankton are significant and show spatial variability possibly induced by varying availability of Fe and other parameters in the region, seawater was collected from CTD (Conductivity, Temperature and Depth) and TMR (Trace Metals Rosette) casts jointly with the nutrient sampling, as well as well as sea-ice collected from Bio ice-core types on Ice Station, for analysis of nitrate d15N, d18O isotopic composition. Results have been interpreted in the light of prevailing nitrate-nutrient concentrations (Belgian team) and N-uptake regimes for the Ice Stations (new vs. regenerated production and nitrification; see Silicon, Carbon and Nitrogen in-situ incubation Metadata file). Methodology and sampling strategy: Samples for isotopic composition of nitrate were collected from the CTD rosette, TMR and Bio ice-core jointly with the nutrient sampling. Sea-ice sampling: sampling strategy follows ice stations deployment via Bio ice-core type. Most of the time we worked close to / directly on the Trace Metal site following precautions concerning TM sampling (clean suits etc.). When we worked close to the TM site, precautions were not such important because we don't need the same drastic precautions for our own sampling. We work together because we want to propose a set of data which helps to characterize the system of functioning in close relation with TM availability (for that, sampling location have to be as close as possible). All samples were filtered on 0.2 microns acrodiscs and kept at -20 degrees C till analysis in the home-based laboratory. We applied the denitrifier method elaborated by Sigman et al. (2001) and Casciotti et al. (2002). This method is based on the isotopic analysis of delta ...
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