Effects of changes in species composition and distribution on contaminant food web accumulation

Abstract

Work description As changes in temperature and sea ice distribution and thickness is expected in the region of interest, the energy transfer processes in the food web are expected to be changed compared to previous decades. Zooplankton and fish samples will be collected focusing on the process study cruises. From these, chemicals representing lipid soluble and protein associated contaminants will be analyzed, in addition to dietary descriptors to trace energy source (stable isotopes and lipid analyses). This will be repeated in the different seasons to interpret the annual dynamics of contaminant accumulation and transfer in the food web related to energy use and availability. So far, seasonal food web data are only available from Arctic fjords. At the UiO stable isotope lab, we will measure bulk C, H, N, O and S in organic material, and thus the ratios between lipid/protein/carbohydrate will be analyzed in small amounts of sample without extraction to assess the proximate biochemical composition. Model predictions of climate change effect on food web accumulation of contaminants include reduced accumulation due to predicted reduction in lipid storage. Bioaccumulation changes due to altered dietary composition is predicted to have less influence than the predicted lower lipid content. These predictions will be tested in the present task. A similar approach of sampling the central Barents Sea pelagic food web was taken in May 1998 (however, only with bulk stable isotope analyses of 13C and 15N), which allows a thorough comparison between the environmental states two decades apart. (From Nansen Legacy implementation plan)