Marine bacterioplankton at the Weddell Sea ice edge, distribution of psychrophilic and psychrotrophic populations
Marine bacterioplankton at the Weddell Sea ice edge, distribution of psychrophilic and psychrotrophic populations
复制标题
威德尔海冰缘的海洋浮游细菌，嗜冷和耐冷种群的分布
作者：
D. Delille
SummaryIn东部威德尔海的几个断面从冰覆盖，通过冰融化，开放的海洋站，总和异养细菌估计文件增强的细菌生物量预计附近的冰边缘。在融化的冰芯中发现了最高数量的细菌，分别为4.2·103 CFU ml −1和1.1·107 Cells ml−1。虽然来自孔隙水样品的盐水平均每毫升的细胞数量少一个数量级以上，但在盐水样品中记录了最高的细菌产量，2.2·107个细胞l−1天−1。所有定量研究的细菌参数都低于冰下的冰样品，但没有明显的垂直梯度的水柱。在所研究的春季情况下，海冰的发生似乎只发挥了很小的作用，在海水浮游细菌的一般分布。对118株分离菌株进行了29项形态学和生化试验，研究了细菌群落结构。南极浮冰上的细菌群落与底层海水中的细菌群落不同。虽然非发酵革兰氏阴性杆菌一直占主导地位的海水中，弧菌属占25%以上的菌株分离，从一些冰样品。结果清楚地表明，绝大多数从海水中分离出的细菌必须被认为是嗜冷的，但真正的嗜冷菌株出现在融化的冰和盐水样品中。
SummaryIn the eastern Weddell Sea on several transects from ice-covered, through ice melt, to open-ocean stations, total and heterotrophic bacteria were estimated to document an enhanced bacteriological biomass expected near the ice edge. The highest numbers of bacteria were found in melted ice cores, with 4.2·103 CFUml−1 and 1.1·107 Cells ml−1. Although brine from pore water samples average more than one order of magnitude less cells per ml, the highest bacterial production, 2.2·107 cells l−1 day−1, was recorded in brine samples. All quantitatively studied bacterial parameters were lower under the ice than in the ice samples but there were no clear vertical gradients in the water column. In the studied spring situation, sea ice occurrence seems to play only a minor role in the general distribution of the seawater bacterioplankton. The bacterial community structure was investigated by carrying out 29 morphological and biochemical tests on 118 isolated strains. The bacterial communities inhabiting Antarctic pack ice differ from those found in underlying seawater. Although non fermentative Gram-negative rods were always dominant in seawater, Vibrio sp. represented more than 25% of the strains isolated from some ice samples. The results clearly indicated that a large majority of the bacteria isolated from seawater must be considered psychrotrophic but that truly psychrophilic strains occurred in melted ice and brine samples.