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Microbial responses to changes in flow status in temporary headwater streams: a cross-system comparison
Catherine M Febria1, Jacob D Hosen2, Byron C Crump3
1Department of Entomology, University of Maryland College Park, MD, USA ; Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science Solomons, MD, USA ; School of Biological Sciences, University of Canterbury Christchurch, New Zealand.
Frontiers in Microbiology
|June 20, 2015
Summary
Microbial communities in headwater streams show consistent composition despite periodic drying, with site conditions, not flow permanence, being the main driver. Network analysis revealed shifts in key microbial taxa between permanent and temporary stream conditions.
Area of Science:
- Environmental Microbiology
- Stream Ecology
- Biogeochemistry
Background:
- Temporary headwater streams experience periodic drying, impacting microbial communities responsible for biogeochemical cycling.
- Understanding microbial responses to wet-dry cycles is crucial, but data is limited due to sampling challenges and methodological variations.
- Flow permanence and drying events are key environmental factors influencing microbial community structure and function in aquatic ecosystems.
Purpose of the Study:
- To compare microbial community structure and function in permanent versus temporary headwater streams.
- To investigate the influence of flow permanence and drying on microbial taxonomic diversity and community composition.
- To assess the impact of different molecular methods (T-RFLP and Illumina MiSeq) on microbial community analysis.
Main Methods:
- Collected and analyzed environmental and microbial community data from permanent and temporary tributaries in Ontario, Canada, and Maryland, USA.
- Utilized 16S rRNA gene sequencing (Illumina MiSeq) and T-RFLP to characterize microbial communities.
- Performed network analysis to identify shifts in microbial associations in response to flow conditions.
Main Results:
- Microbial community composition was primarily related to site-specific conditions rather than flow permanence or drying events, irrespective of the molecular method used.
- Network analysis at Parkers Creek revealed distinct microbial associations: methanotrophic taxa dominated permanent streams, while Nitrospirales dominated temporary streams, especially during dry periods.
- Results showed significant variability in microbial responses to drying across different studies globally.
Conclusions:
- Flow permanence and site-specific factors are stronger determinants of microbial community composition in headwater streams than periodic drying.
- Shifts in microbial network structure, particularly involving methanotrophs and Nitrospirales, occur between permanent and temporary stream conditions.
- Further research is needed to develop hypotheses explaining contradictory findings and to understand microbial responses to flow fluctuations.
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