Aislabie J, Ryburn J, Sarmah A
Landcare Research, Private Bag 3127, Hamilton, New Zealand.
Can J Microbiol. 2009 Jan;55(1):12-20. doi: 10.1139/W08-118.
The objective of this study was to investigate the culturable psychrotolerant microbial community in groundwater from Seabee Hook, Antarctica. Shallow groundwater can be present in coastal regions at higher latitudes during the Antarctic summer. Perched groundwater atop ice-cemented permafrost occurs on Seabee Hook, Cape Hallett, at depths from 5 to 80 cm below the soil surface. Compared with terrestrial water from other sites in Antarctica, the groundwater was high in salt and nutrients, reflecting proximity to the sea and ornithogenic soil. Microbial communities in groundwater samples from Seabee Hook exhibited aerobic metabolism of 14C-acetate at 5 degrees C. Numbers of culturable aerobic heterotrophs in the samples ranged from <10 to ca. 1 x 106 colony-forming units.mL-1, and similar numbers of microaerophiles and nitrate reducers were detected. In contrast, numbers of nitrifiers, sulfate reducers, and iron reducers were up to 1000-fold lower. All cultures were incubated at 5 degrees C. Aerobic heterotrophic bacteria isolated from the groundwater were assigned to Actinobacteria, Proteobacteria, or Bacteroidetes. The isolates were most similar to cultured bacteria from Antarctic soil or sediment and were cold, salt, and alkaline pH tolerant, indicating they are adapted to in situ conditions.
本研究的目的是调查南极洲海豹湾地下水中可培养的耐冷微生物群落。在南极夏季，高纬度沿海地区可能存在浅层地下水。在哈雷特角的海豹湾，冻结永冻层之上的上层滞水出现在土壤表面以下5至80厘米深处。与南极洲其他地点的陆地水相比，该地下水的盐分和养分含量较高，这反映了其与海洋和鸟粪土的接近程度。海豹湾地下水样本中的微生物群落在5℃时表现出对14C-乙酸盐的有氧代谢。样本中可培养的需氧异养菌数量范围为<10至约1×106菌落形成单位·mL-1，并且检测到数量相似的微需氧菌和硝酸盐还原菌。相比之下，硝化细菌、硫酸盐还原菌和铁还原菌的数量低至1000倍。所有培养物均在5℃下孵育。从地下水中分离出的需氧异养细菌被归类为放线菌、变形菌或拟杆菌。这些分离物与来自南极土壤或沉积物的培养细菌最相似，并且耐冷、耐盐和耐碱性pH，表明它们适应原位条件。
