Niches of marine mammals in the European Arctic

The Arctic is warming rapidly, with concomitant sea ice losses and ecosystem changes. animals most vulnerable to food web changes are long-lived slow-growing such as marine mammals, which may not be able adapt rapidly enough respond in their resource bases. To determine the current extent sources of these bases, we examined isotopic trophic niches for mammals European using skin carbon (?13C) nitrogen (? 15N) stable isotope (SI) compositions from 10 species: blue, fin, humpback, minke, sperm white whales, bearded ringed seals, walruses polar bears, dietary fatty acids (FAs) whale species listed here. SI values showed clear separation by behaviour sources. Bearded whales had smallest niches; all resident High likely particularly ecosystems. We found between FA groupings driven pelagic, benthic planktonic/algal sources: pelagic FAs walruses, copepod/algae/dinoflagellate some bear approaching those walruses. There strong niche partitioning study minimal functional redundancy, could impact structure connectivity if populations large nutrient vectors reduced or lost.