Occurrence of an algal bloom under Arctic pack

Summer melting of sea ice leads to the formation of under-ice melt ponds in Arctic seas. The biological characteristics oi such a pond were studied in summer 1993. The chlorophyte Pyramimonas sp. (Prasinophyceae) formed a unialgal bloom with cell densities of 19.1 x 10(3) 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.