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Spatial Variability in Streambed Microbial Community Structure across Two Watersheds.
Philips O Akinwole1,2, Jinjun Kan3, Louis A Kaplan3
1Biology Department, DePauw University, Greencastle, Indiana, USA.
Microbiology Spectrum
|December 15, 2021
Summary
Microbial communities in headwater streams show distinct watershed-level biogeography. Environmental factors like sediment C:N ratio and microeukaryotic photoautotrophs influence microbial biomass and structure.
Area of Science:
- Environmental Microbiology
- Aquatic Ecology
- Biogeography
Background:
- Spatial and temporal variability are crucial for sedimentary microbial communities.
- Understanding fine-scale spatial variability in headwater stream microbial communities is limited.
- Microorganisms drive significant biogeochemical reactions in streams.
Purpose of the Study:
- Investigate microbial community structure (MCS) in streambed sediments across various spatial scales.
- Determine factors influencing microbial biomass and community composition in headwater streams.
- Elucidate the role of microeukaryotic photoautotrophs in structuring bacterial communities.
Main Methods:
- Analyzed phospholipid fatty acid (PLFA) profiles for microbial community structure.
- Utilized PCR-denaturing gradient gel electrophoresis (PCR-DGGE) for bacterial community analysis.
- Assessed microbial biomass and correlated it with sediment characteristics (C:N ratio, carbon content, surface area, water content).
Main Results:
- Microbial community structure varied significantly at the watershed level, indicating distinct biogeography.
- Microeukaryotic photoautotrophs were key drivers of variations in microbial community structure and biomass.
- Sediment characteristics, particularly C:N ratio, explained a substantial portion (68%) of microbial biomass variation in first-order streams.
Conclusions:
- Headwater stream microbial communities exhibit nonrandom, watershed-level biogeography.
- Environmental heterogeneity and geographical distance are significant drivers of microbial distribution.
- Eukaryotic photoautotrophs play a critical role in shaping bacterial communities within streambed sediments.
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