Ice matters. Under-ice fauna surveys in the Arctic and Antarctic Oceans

• Main Authors: Flores, Hauke, David, Carmen, Lange, Benjamin, van Franeker, J.-A., Siegel, Volker, Pakhomov, E. A., Hunt, B. P. V., Van de Putte, A. P., Tonkes, Henrieke, Nicolaus, Marcel, Fernandez Mendez, Mar, Niehoff, Barbara, Peeken, Ilka
• Format: Conference Object
• Language: unknown
• Published: 2013
• Subjects: Antarc*; Antarctic; Antarctic Krill; Arctic; Arctic cod; Arctic Ocean; Boreogadus saida; Euphausia superba; Sea ice; Southern Ocean; Copepods
• Online Access: https://epic.awi.de/id/eprint/35432/; https://epic.awi.de/id/eprint/35432/1/Flores_SCARbiolXI_17Jul2013.pdf; https://hdl.handle.net/10013/epic.43404; https://hdl.handle.net/10013/epic.43404.d001

In the Polar Regions, sea ice habitats are undergoing rapid environmental change. Because sea ice constitutes an important substrate for numerous species, as well as an important carbon source during critical periods of the year, these changes have a significant impact on ecosystem functioning, biodiversity, species distribution, and population sizes of both commercially exploited species, and species valuable from a conservation perspective. Species dwelling at the ice-water interface (e.g. Antarctic krill Euphausia superba and Arctic cod Boreogadus saida) are assumed to play key roles in these ecosystems. As an important trophic carbon transmitter from the sea ice into pelagic food webs and ultimately to the deep sea benthos, under-ice fauna can contribute significantly to the carbon flux in polar ecosystems. Whether the function of Arctic and Antarctic under-ice communities as trophic carbon transmitters is comparable in spite of great differences in the environmental regimes of the two Polar Oceans, however, is an open question. Quantifying under-ice communities was hampered in the past by the inaccessibility of the ice underside to conventional sampling gear. Using a new under-ice trawl, it was demonstrated that Antarctic krill concentrates under sea ice almost year-round, and that krill dwelling under ice are often under-estimated by pelagic nets and sonars. A diverse suite of species, including copepods, amphipods and pteropods, shares this attraction to the Antarctic ice underside at least temporarily. An Arctic expedition in 2012 using an improved version of this sampling gear brought evidence of a similarly rich under-ice community even in the biologically poor-considered central Arctic Ocean. Using a bio-environmental sensor array during under-ice fishing enabled fine-scale characterization of sea ice habitat properties as a basis for statistical modeling of under-ice species distribution. In the Arctic sea ice system, the trophic role that in the Southern Ocean is attributed to Antarctic krill may be ...