Patterns of variability in the fatty acid and stable isotope profiles of ice algae, phytoplankton, and zooplankton during early spring in the Canadian High Arctic

Sea ice-associated primary producers are a major source of energy within Arctic marine ecosystems, particularly when pelagic primary growth is temporally and spatially limited. Using samples and data collected in spring 2011 and 2012, the variation in the fatty acid composition and stable isotopes of ice-based primary producers and primary consumers were investigated over several spatial scales in the Canadian Arctic Archipelago. Snow and ice thickness significantly affected ice algae fatty acid composition. Broad scale year-to-year variation in snow and ice conditions indirectly affected the fatty acid compositions, particularly the levels of polyunsaturated fatty acids, of a keystone zooplankton species. Environmental influence on fatty acid composition decreased as trophic level increased. Despite the presence of high quality pelagic phytoplankton under the sea ice, the data suggest herbivores rely mainly on ice algae.