Floating Ice-Algal Aggregates below Melting Arctic Sea Ice

摘要: During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm diameter) had a mucous consistency were dominated by typical ice-associated pennate diatoms embedded within matrix. Aggregates maintained buoyancy accumulated just above strong pycnocline that separated meltwater seawater layers. We able, for first time, obtain quantitative abundance biomass estimates these aggregates. Although their production on square metre basis was small compared ice-algal blooms, supported high levels biological activity scale individual aggregate. In addition they constituted food source fauna as revealed pigments indicative zooplankton grazing, naked ciliates, amphipods associated with them. melt season, likely play an important ecological role otherwise impoverished near-surface sea environment. Our findings provide observations measurements unique aggregate-based habitat during 2012 record minimum year.