Transfer of ice algae carbon to ice-associated amphipods in the high-Arctic pack ice environment

Sympagic (ice-associated) amphipods channel carbon into the marine ecosystem. With Arctic sea ice extent in decline, it is becoming increasingly important to quantify this transfer of sympagic energy. Recently, a method for quantifying sympagic particulate organic carbon (iPOC) in filtered water samples was proposed based on the abundances of the Arctic sea ice biomarker IP25. Here, we tested the hypothesis that adoption of this method could also provide quantitative estimates of iPOC transfer within Arctic amphipods. We analysed five amphipod species collected north of Svalbard and compared findings to some previous studies. Estimates showed that Onisimus glacialis and Apherusa glacialis contained the most iPOC, relative to dry mass (23.5 ± 4.5 and 9.8 ± 1.9 mg C g−1, respectively), while Gammarus wilkitzkii had the highest grazing impact on the available ice algae (0.48 mg C m−2, for an estimated 24 h), equating to 73% of algal standing stock. Our findings are also broadly consistent with those obtained by applying the H-Print biomarker approach to the same samples. The ability to obtain realistic quantitative estimates of iPOC transfer into sympagic and pelagic fauna will likely have important implications for modelling energy flow in Arctic food webs during future climate scenarios.