Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China
Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China
复制标题
DOI：
10.1128/aem.02869-05
复制
发表时间：
2006-06-01
影响因子：
4.4
通讯作者：
Fields, Matthew W.
中科院分区：
文献类型：
--
作者：
Jiang, Hongchen;Dong, Hailiang;Fields, Matthew W.
本文采用非培养和培养相结合的方法对茶卡湖微生物多样性进行了研究。它位于海拔3，214米，气候干燥。平均水深为2至3厘米。从湖水中分离到嗜盐菌株，从浅水沉积物中分离到耐盐菌株。分离株表现出抗紫外线和γ辐射。沉积物中的微生物丰度从水-沉积物界面处的108个细胞/克到沉积物深度42厘米处的107个细胞/克不等。在整个界面上观察到细菌群落组成的重大变化。在湖水中，拟杆菌属的克隆序列是最丰富的，而在沉积物中，低G+C革兰氏阳性菌相关的序列占主导地位。在古菌群落中也出现了类似的变化。虽然湖水中的所有古菌克隆序列属于盐杆菌目，但沉积物中的大多数序列与先前从产甲烷土壤和沉积物中获得的序列有关。在整个水-沉积物界面的微生物群落结构中观察到的变化与从湖水（32.5%）到沉积物（约4%）的盐度降低相关。在整个界面上，氧化还原状态也从好氧变为缺氧，这也可能是导致微生物群落发生变化的原因。
We employed culture-dependent and -independent techniques to study microbial diversity in Lake Chaka, a unique hypersaline lake (32.5% salinity) in northwest China. It is situated at 3,214 m above sea level in a dry climate. The average water depth is 2 to 3 cm. Halophilic isolates were obtained from the lake water, and halotolerant isolates were obtained from the shallow sediment. The isolates exhibited resistance to UV and gamma radiation. Microbial abundance in the sediments ranged from 108 cells/g at the water-sediment interface to 107 cells/g at a sediment depth of 42 cm. A major change in the bacterial community composition was observed across the interface. In the lake water, clone sequences affiliated with the Bacteroidetes were the most abundant, whereas in the sediments, sequences related to low G+C gram-positive bacteria were predominant. A similar change was also present in the archaeal community. While all archaeal clone sequences in the lake water belonged to the Halobacteriales, the majority of the sequences in the sediments were related to those previously obtained from methanogenic soils and sediments. The observed changes in the microbial community structure across the water-sediment interface were correlated with a decrease in salinity from the lake water (32.5%) to the sediments (approximately 4%). Across the interface, the redox state also changed from oxic to anoxic and may also have contributed to the observed shift in the microbial community.