关键词: 南极,固定冰,冰藻,叶绿素a,季节变化

Abstract:

The ice algae communities at three sites near Zhongshan Station (69°22′24″S,76 °22′40″E),east Antarctica were monitored from April to December 1992. The maximum ice thickness was 1.74m in November and covered snow was less than 30cm in depth through the year. 2 or 3cm brown layers occurred in the bottom ice in later April and November,with highest chlorophyll a values of 88.3 and 2810mg/m 3 respectively,and the comparing cell numbers were 3.5×10 6 and 1.21×10 8cells/l. The maximum integrated chlorophyll a value was 59.7mg/m 2 in November and the values had never exceeded 6mg/m 2 before mid October. Most of the biomass occured in the bottom ice and more than 95 percent of it was concentrated in the bottom 15cm ice layer during ice algae bloom. The dominant diatoms included Nitzschia lecointei,N. barkleyi and N. cylindrus in austral autumn,and Amphiprora kjellmanii,Berkeleya rutilans,Nitzschia lecointei in austral spring,and had some difference depending on the sites and environmental conditions. The results show that the composition of dominant species of ice algae and the biomass in austral spring were similar to that of other fast ice sites in east Antarctica but very different from that of sub Antarctica.