Trophic interactions of copepods - application of natural abundance of stable isotopes

Natural abundance isotope ratio (NAIR) signatures will be determined for components of the zooplankton food chain collected during Phase 2 Marine Productivity cruises in the North Atlantic. This will enable the detection of shifts in trophic level and diet for individual species over geographic and temporal transects, and the detection of differences in diet between different species inhabiting the same water column. We shall also attempt to determine corrective algorithms for the determination of NAIR signatures in preserved zooplankton enabling a future interpretation of CPR records. The approach is core to the MarProd hypotheses concerning the trophic activity of zooplankton and the only method covering meaningful periods of time between cruises.