Dataset Information

Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China.

ABSTRACT: 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 10(8) cells/g at the water-sediment interface to 10(7) 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.

SUBMITTER: Jiang H

PROVIDER: S-EPMC1489620 | biostudies-literature | 2006 Jun

REPOSITORIES: biostudies-literature

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Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China.

Jiang Hongchen H Dong Hailiang H Zhang Gengxin G Yu Bingsong B Chapman Leah R LR Fields Matthew W MW

Applied and environmental microbiology 20060601 6

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 10(8) ...[more]

PMID: 16751487

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Project description:BackgroundMicroorganisms in rivers and lakes are essential for nutrient recycling in aquatic ecosystems. Understanding the ecological processes shaping microbial communities is of crucial importance for aquatic microbial ecology and biogeography. However, the diversity of microorganisms and the forces that control this diversity are poorly understood. This is particularly true within the framework of the river-lake continuum in arid regions.ResultsUsing a whole catchment-sampling effort, we explored biogeographical patterns and mechanisms of microbial community (bacteria and archaea) assembly within the catchment of the largest inland once freshwater lake (Lake Bosten) in China. Water samples from headstream tributaries, the mainstream of the River Kaidu to downstream Lake Bosten were characterized using amplicon sequencing of 16S rRNA genes. Higher α-diversity was found in mainstream of River Kaidu and in the tributaries compared with Lake Bosten. And the microbial community composition was also significantly different between the lake and its connected river habitats. Canonical correspondence analysis demonstrated that salinity and total suspended solids were the most important environmental factors shaping the community variations. Overall, pure environmental and pure spatial factors explained 13.7 and 5.6% of the community variation, respectively, while 32.0% of the variation was explained by combined environmental and spatial variables. These observations suggested that spatially structured environmental variations mainly shaped the microbial biogeography in this region. Both deterministic and stochastic processes influenced the microbial community assembly in river and lake habitats, and the stochastic pattern was particularly pronounced for microbiome in river habitat. Co-occurrence network analysis revealed more abundant and complicated correlations among frequently occurred taxa in lake habitat compared with the river habitat, implying that ecological multispecies interactions (e.g., competition) shaped lake microbial community structures.ConclusionsOur findings demonstrate an ecological succession along the river-lake continuum of microbial communities across the largest inland once freshwater lake basin in China, and highlight the effects of spatially structured environmental factors on regional microbial β-diversity and species interactions on local community assembly.

Project description:In river-lake systems, sediment and water column are two distinct habitats harboring different bacterial communities which play a crucial role in biogeochemical processes. In this study, we employed Phylogenetic Investigation of Communities by Reconstruction of Unobserved States to assess the potential functions and functional redundancy of the bacterial communities in sediment and water in a eutrophic river-lake ecosystem, Poyang Lake in China. Bacterial communities in sediment and water had distinct potential functions of carbon, nitrogen, and sulfur metabolisms as well as phosphorus cycle, while the differences between rivers and the lake were inconspicuous. Bacterial communities in sediment had a higher relative abundance of genes associated with carbohydrate metabolism, carbon fixation pathways in prokaryotes, methane metabolism, anammox, nitrogen fixation, and dissimilatory sulfate reduction than that of water column. Bacterial communities in water column were higher in lipid metabolism, assimilatory nitrate reduction, dissimilatory nitrate reduction, phosphonate degradation, and assimilatory sulfate reduction than that of sediment bacterial communities. Furthermore, the variations in functional composition were closely associated to the variations in taxonomic composition in both habitats. In general, the bacterial communities in water column had a lower functional redundancy than in sediment. Moreover, comparing to the overall functions, bacterial communities had a lower functional redundancy of nitrogen metabolism and phosphorus cycle in water column and lower functional redundancy of nitrogen metabolism in sediment. Distance-based redundancy analysis and mantel test revealed close correlations between nutrient factors and functional compositions. The results suggested that bacterial communities in this eutrophic river-lake system of Poyang Lake were vulnerable to nutrient perturbations, especially the bacterial communities in water column. The results enriched our understanding of the bacterial communities and major biogeochemical processes in the eutrophic river-lake ecosystems.

Dataset Information

Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China.

Publications

Microbial diversity in water and sediment of Lake Chaka, an athalassohaline lake in northwestern China.

Similar Datasets

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