北极巴伦支海和拉普捷夫海海冰中细菌和微藻的垂直分布

Vertical distribution of bacteria and their relation to algal biomass in the high arctic sea ice from the Barents Sea and Laptev Sea

通过计算机图像测定系统测定、计算获得海冰细菌的大小、面积和碳含量,研究了北极巴伦支海和拉普捷夫海的浮冰中细菌大小、丰度和生物量的垂直分布及其与海冰微藻生物量的关系.细菌在冰心中是非均匀分布的,至少有两种不同分布类型:第一类有单一的丰度峰值,在冰心底部或在冰心中部;第二类有两个丰度峰值.海冰中细菌的丰度为0.4×105～36.7×105个/cm3.不同类型海冰中的细菌大小变化极大,在多年冰中,最大的细菌与叶绿素a最大值出现在同一层,而在一年冰中,细菌大小几乎没有垂直变化.整柱冰心的细菌生物量变化为19.2～79.2mg/cm2,细菌与海冰微藻生物量之比为0.43～10.00.对固定冰比较和研究的结果发现,海冰冰心中细菌大小、丰度和生物量的垂直分布差别极大.据此,分析了对目前海冰研究采样方法的局限性,并提出了规范采样方法的设想.

The vertical distribution of bacterial abundance and biomass were investigated in relation to algal biomass in ice cores taken from drifting ice floes in two arctic shelf areas: the Barents Sea and the Laptev Sea. The individual size and carbon content of a single sea ice bacterium was determined by means of image analysis. Bacteria were not evenly distributed but occurred in dense layers. At least two different types of distribution patterns were found with either a single maximum inside or at the bottom of the ice floe or two maxima in different parts of the floes. Bacterial concentrations range from 0.4×10~5 to 36.7×10~5 cells/cm^3. The individual cell size exhibits considerable variations between the ice floes. In a multi-year ice floe, the largest bacteria were observed in relation to an internal chlorophyll a maximum, while no vertical changes were found in first-year ice floe. Total bacterial biomass (C) for the entire ice cores ranges from 19.2 to 79.2 mg/cm^2 and the ratio of bacterum to ice algal biomass from 0.43 to 10.00. A comparison with data collected from fast ice reveals large differences in cell size, abundance and biomass. Based on these comparisons limitations in the methodological approaches used in current sea ice research are analyzed and a standardized sampling scheme for sea ice cores is proposed.