Increased Denitrification Rates Associated with Shifts in Prokaryotic Community Composition Caused by Varying
Abigail Tomasek1,2, Christopher Staley3, Ping Wang3
1St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, United States.
Frontiers in Microbiology
|December 8, 2017
Summary
Hydrologic connectivity, not location or time, significantly impacts denitrification rates and microbial communities in agricultural watersheds. Periodic flooding enhances denitrification potential, offering a natural remediation strategy.
Area of Science:
- Environmental Microbiology
- Biogeochemistry
- Agricultural Science
Background:
- Modern agriculture impacts biogeochemical cycles, particularly nitrogen transformation.
- Denitrification by microbes removes nitrate, offering natural water remediation.
- Previous work showed inundation links denitrification genes and rates, but this varies with hydrologic conditions.
Purpose of the Study:
- To investigate how hydrologic regimes influence microbial communities and denitrification rates.
- To assess the relationship between microbial community composition, denitrification genes, and rates.
- To explore the potential of hydrologic management for bioremediation in agricultural watersheds.
Main Methods:
- Utilized Illumina next-generation sequencing for microbial community analysis.
- Collected samples over 2 years from three sites along a creek in an agricultural watershed.
- Analyzed denitrification rates, gene abundances, and prokaryotic community composition in relation to hydrologic connectivity.
Main Results:
- Hydrologic connectivity significantly influenced denitrification rates, gene abundances, and prokaryotic communities more than spatiotemporal factors.
- Denitrification rates positively correlated with nitrate concentration and denitrification gene abundances.
- Specific bacterial families (e.g., Burkholderiaceae, Anaerolinaceae) were positively correlated with denitrification rates.
Conclusions:
- Hydrologic connectivity is a primary driver of microbial community shifts and denitrification potential.
- Inundation is associated with increased denitrification potential, suggesting a role for periodic flooding in remediation.
- Complex interactions exist, but hydrologic connectivity, microbial composition, and genetic potential offer promising avenues for water quality management.
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