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Do patterns of bacterial diversity along salinity gradients differ from those observed for macroorganisms?
Jianjun Wang1, Dongmei Yang, Yong Zhang
1State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
Plos One
|November 30, 2011
Summary
Bacterial biodiversity in Tibetan lakes initially increases with salinity but then plateaus. This challenges the idea that extreme environments always have lower microbial diversity, suggesting complex evolutionary forces at play.
Area of Science:
- Microbial Ecology
- Environmental Microbiology
- Evolutionary Biology
Background:
- Biodiversity generally decreases in extreme environments for macroorganisms.
- The trend of reduced biodiversity in extreme environments is less understood for microbial communities, specifically bacteria.
Purpose of the Study:
- To investigate if the trend of lower biodiversity in extreme environments applies to bacterial communities.
- To determine the influence of salinity on bacterial taxon richness and community composition in Tibetan lakes.
Main Methods:
- Utilized denaturing gradient gel electrophoresis (DGGE) with phylum-specific primers to quantify bacterial taxon richness.
- Analyzed bacterioplankton communities from 32 pristine Tibetan lakes across a wide salinity range.
- Compared 16S rRNA gene clone libraries from freshwater and hypersaline lakes.
Main Results:
- Salinity was the primary environmental factor influencing bacterial community composition.
- Bacterial taxon richness increased with salinity up to 1‰, after which it did not decrease in more saline systems.
- Hypersaline lake bacterial communities showed higher recent diversification but lower phylogenetic diversity compared to freshwater lakes.
Conclusions:
- The relationship between salinity and bacterial diversity in Tibetan lakes is complex and does not follow the simple inverse trend seen in macroorganisms.
- Different evolutionary pressures may shape bacterial communities in freshwater versus hypersaline lake environments.
- Findings highlight the need for nuanced understanding of microbial diversity patterns in relation to environmental extremes.
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