Occurrence of an algal bloom under Arctic pack ice

Abstract

Summer melting of sea ice leads to the formation of under- ice melt ponds in Arctic seas. The biological characteristics of such a pond were studied in summer 1993. The chlorophyte Pyramimonas sp. (Prasinophyceae) formed a unialgal bloom with cell densities of 19.1 x 103 cells ml-1 and a pigment concentration of 29.6 mg m-3. A comparison with ice core data revealed differences in algal biomass and community structure. Physical data indicate that under-ice ponds are a common feature in the Arctic Ocean. Thus, communities within under-ice ponds, which have not been included in production estimates, may significantly contribute to the Arctic marine food web.