Bulk stable isotopes of carbon and nitrogen in benthic epifauna, infauna and zooplankton collected from the Barents Sea during the Nansen Legacy project 2018-2021

This dataset provides bulk stable isotope values of carbon and nitrogen for benthic fauna and some zooplankton collected in the Barents Sea during five sampling campaigns during 2018-2021; August 2018, August 2019, December 2019, March 2021 and May 2021. Benthic epifauna were collected using a Campelen or beam trawl and infauna were collected using a box corer. During the 2018 sampling campaign, zooplankton was also collected using a Harstad trawl. Upon collection, all fauna were sorted and identified to the lowest taxonomic level possible while in cold water. Muscle tissue was sub-sampled from large taxa while small taxa were kept whole. All samples were frozen at -20°C until further analysis. In the laboratory, samples were thawed slightly to allow for sub-sampling as needed, then freeze dried for 48 hours. After freeze drying, samples were ground to a fine powder using a mortar and pestle and approximately 1mg of sample was packed into tin capsules for isotopic and elemental analysis. For taxa containing carbonate (e.g., shells, echinoderms) a sub-sample of the freeze-dried powder was also acidified with 1M hydrochloric acid using a dropwise method until visible dissolution ceased. These sub-samples were then re-dried in an oven and packed into tins for analysis like the non-acidified samples. All samples were analyzed for carbon and nitrogen content and isotope ratios at the CLIPT laboratory at the University of Oslo using the Thermo Fischer Scientific 230 EA IsoLink IRMS system comprised of a DeltaV Advantage Stable Isotope Mass Spectrometer coupled to a Flash Elemental Analyzer. The resulting isotope data are reported in delta notation: δnX (‰) = [(Rsample – Rstandard) / Rstandard ] x 1000 where R is the ratio of heavy:light isotopes of the element X in our sample relative to the reference standards Vienna PeeDee Belemnite (VPDB, carbon, Craig, 1957) and air (nitrogen, Mariotti, 1983). During analysis, internal reference standards L-glutamic acid and glycine were calibrated to the International Atomic Energy Agency standards calcium carbonate (NBS19) and lithium carbonate (LSVEC) to normalize carbon isotope values to the δ13CVPDB-scale as well as to USGS40 and USGS41 to normalize nitrogen isotope values to the δ15NAIR-scale. The carbon and nitrogen content data are reported in weight percent.