关键词: 冰藻;浮游植物;群落结构;生物量;拉普捷夫海;北极

Abstract:

Species composition, abundance and biomass of ice algal and underlying phytoplankton communities were investigated in southeastern Laptev Sea in spring 1999. Diatoms were predominant in algal species and pennate diatoms were dominant in diatom species. 12 dominant algal species occurred in ice and underlying water column, which included Fragilariopsis oceanica, F. cylindrus, Nitzschia frigida, N. promare, Achnanthes taeniata, Nitzschia neofrigida, Navicula pelagica, N. vanhoeffenii, N. septentrionalis, Melosira arctica, Clindrotheca closterium and Pyramimonas sp. The algal abundance within bottom 10cm sea ice were between 14.6 and 1562.2 ×10 4 cells·L -1 with an average of 639.0 ×10 4 cells·L -1 , and the algal biomass were between 7.89 and 2093.5 μg C·L -1 with an average of 886.9 μg C·L -1 , which were about one magnitude higher than those of sub-bottom and two magnitude higher than those of underlying surface water. The integrated algal abundance and biomass within bottom 20cm ice column were averagely 7.7 and 12.2 times as those in underlying 20m water column, respectively, suggesting that the ice algae might play an important role in maintaining the coastal marine ecosystem before the melting of sea ice. The influence of ice algae to the phytoplankton community was obvious although the similarities of algal community in ice bottom and water surface were not high in many sites. But the “seeding” of ice algae to phytoplankton was low because the abundance and biomass in water column were much lower than those in bottom ice and no rapid growth occurred within phytoplankton community.