This data features stable carbon and nitrogen isotopes of co-occurring Southern Ocean pteropods in order to estimate and compare their Bayesian isotopic niches. Other data includes station number, latitude and longitude, species names and sample ID. Details for each column are as follows: A: "species" - Species analysed including, "clio" = Clio pyramidata f. sulcata; "clione" = Clione limacina antarctica; "spongio" = Spongiobranchaea australis; "Large-fraction POM" = large-fraction particulate organic matter; "Small-fraction POM" = small-fraction particulate organic matter B: "speciesID" - Sample ID = unique identifier from Central Science Laboratory, University of Tasmania C: "station" = CTD number (KAxis research voyage) D: "date" = Date of sample (RMT-8 net trawl, KAxis research voyage) E: "lat" = Latitude (degS) F: "long" = Longitude (degE) G: "%C" = percent carbon (no unit) H: "%N" = percent nitrogen (no unit) I: "C:N (bulk)" = uncorrected (raw) carbon-to-nitrogen ratio (no unit) J: "delta 13C (bulk)" = uncorrected (raw) stable carbon isotope values (‰) H: "delta 15N (bulk)" = uncorrected (raw) stable nitrogen isotope values (‰) L: "notes" = samples may be duplicated or triplicated M: "atomic C:N" = C:N (bulk) x 14/12 (no unit) N: "atomic L" = 93/(1+ (1/((0.246 x atomic C:N) - 0.775))) O: "L" = 93/(1+(1/((0.246 x C:N (bulk) - 0.775))) P: "delta 13C (Kiljunen)" = delta 13C (bulk) corrected using formula by Kiljunen et al. 2006 Q: "delta 13C (atomic Kiljunen)" = delta 13C (bulk) corrected using formula by Kiljunen et al. 2006 and atomic L value (column N) R: "delta 13C (Post)" = delta 13C (bulk) corrected using formula by Post et al. 2007 S: "delta 13C (Weldrick)" = delta 13C (bulk) corrected using formula by Weldrick et al. 2019 T: "delta 13C (atomic Smyntek)" = delta 13C (bulk) corrected using formula by Smyntek et al. 2007 and atomic L value (column N) U: "delta 13C (Smyntek)" = delta 13C (bulk) corrected using formula by Smyntek et al. 2007 V: "delta 13C (Logan)" = delta 13C (bulk) corrected using formula by Logan et al. 2008 W: "delta 13C (Syvaranta)" = delta 13C (bulk) corrected using formula by Syvaranta and Rautio 2010 The analysis is featured within a recently accepted paper titled "Trophodynamics of Southern Ocean pteropods on the southern Kerguelen Plateau" peer-reviewed for Ecology and Evolution (2019). It is based on samples collected during the KAxis research voyage, 2015/16.

Krill, salps and pteropods were collected with an RMT8 net during the K-Axis cruise. Specimens were removed from the samples, measured and frozen at -20C until ready for analysis in Hobart. Individuals of known species were dried at -60C, ground to a fine powder, encapsulated into tin cups and analysed with an ICP-MS in the Central Science Laboratories, University of Tasmania. Samples were analysed for delta15N and delta13C. The salp was the common Southern Ocean species Salpa thompsoni and the krill were Euphausia superba, E. triacantha, E. frigida and Thysanoessa macrura. A small number (2) of the siphonphore Diphyes antarctica were also analysed. Pteropods analysed included both shelled (thecosomes) and naked (gymnosomes) pteropods. Columns E-O in the Pteropods worksheet in the spreadsheet are expressed as ratios.