Ecological Characteristics Of Ice Algae In Typical Sea Ice Biotope In The Arctic Ocean

Our knowledge of the Arctic Ocean ecosystem is still limited especially that at high altitude due to its severe conditions and inaccessibility . In this paper, ice algae of the summer pack ice in the Canada Basin and the spring fast ice in the Laptev Sea were surveyed, in order to dig the knowledge of the Arctic ice algal groups further.Algal abundance of the pack ice in the Canada Basin in summer 2003 was 1.28～87.27×10⁴cells·L^-1 with an average of 15.56×10⁴cells·L^-1, including those in the water-ice interface. The algal biomass was 0.559～89.49μgC·L^-1 with an average of 12.57μgC·L^-1 which was far less than the previous reports. Abundance in the 10cm bottom ice was at least 1 magnitude higher than that of the surface water. The ice algal production increased with increasing ice temperature. The vertical distribution pattern of them as a whole was a waving curve with peak values locating in the upper part of the pack ice. Pennate diatoms, primarily including Cylindrus closterium, Nitzschia frigida, Nitzschia neofrigida, Nitzschia arctica, Nitzschia polaris, Fragilariopsis cylindrus, etc. were predominant in the ice algal groups. Spores especially Chaetoceros spores, were abundant and spreading to each level, reaching their maximum values on the surface water and the upper part of the ice. Algal diversity was fairly high in spite of being at decadent phase. Similarity was not evident between ice algal groups of bottom ice and those of water-ice interface, showing insignificant influence of common"seeding"effect. Distribution pattern of ice algae was found not to correlate to other members of microbial loop in ice either. But the impact of global warming on the ice algal community seemed evident for reducing ice depth, decline of ice algal production, absence of bottom ice bloom, flooding of fresh chlorophytes and dominance of cosmopolitan species including Cylindrus closterium,Nitzschia delicatissima, etc..The ice algal abundance of 10cm bottom ice of the fast ice collected from the southeastern Laptev Sea, Arctic Ocean in spring 1999 was 14.6¹562.2×10⁴ cells·L^-1 with an average of 639.0×10⁴ cells·L^-1, which was 1 magnitude and 2 magnitude...