Deep-sea megabenthos communities of the Eurasian Central Arctic are influenced by ice-cover and sea-ice algal falls

摘要: Quantitative camera surveys of benthic megafauna were carried out during the expedition ARK-XXVII/3 to Eastern Central Arctic basins with research icebreaker Polarstern in summer 2012 (2 August-29 September). Nine transects performed for first time deep-sea areas previously fully covered by ice, four them Nansen Basin (3571-4066m) and five Amundsen (4041-4384m). At seven these stations Agassiz trawls taken near tracks species identification. The observed was largely endemic. Several taxa showed a substantially greater depth or geographical range than assumed. Variations composition structure megabenthic communities analysed linked several environmental variables, including state sea ice phytodetritus supply seafloor. Three different types identified based on dominating biomass. Among actiniarian Bathyphellia margaritacea holothurians Elpidia heckeri Kolga hyalina. megafaunal abundance all related proximity marginal zone. Stations located closer this zone characterized relatively high densities biomass B. (mean 0.2-1.7 ind m-2; 0.2-1.5 g ww.m-2). food higher at stations, as suggested enhanced concentrations pigments, organic carbon, bacterial cell abundances porewater nutrients sediments. ice-covered North Pole partially under multi-year lower same biogeochemical indicators supply. These nevertheless hosted density E. 0.9-1.5 0.3-0.4 ww.m-2) K. hyalina 0.004-1.7 0.01-3.5 ww.m-2), which feed large falls sea-ice colonial diatom Melosira arctica. link between community extent condition cover suggests that future climate changes may affect deep ocean biodiversity.