| Summary: | Progress Code: completed Statement: No problems with data collection or analysis. Purpose The stable isotope analysis of zooplankton was performed as part of the studies designed to understand trophic interactions in the planktonic food web over the Kerguelen Plateau. In particular, we wished to understand (i) the trophic positions of key krill species and how they interacted with Salpa thompsoni and (ii) the roles of naked and shelled pteropods in the food web. 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.
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