Snowmelt Induced Hydrologic Perturbations Drive Dynamic Microbiological and Geochemical Behaviors across a Shallow Riparian Aquifer
- The Ohio State Univ., Columbus, OH (United States). Dept. of Microbiology
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Hydrology Group
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division
- The Ohio State Univ., Columbus, OH (United States). Dept. of Microbiology and School of Earth Sciences
Shallow riparian aquifers represent hotspots of biogeochemical activity in the arid western US. While these environments provide extensive ecosystem services, little is known of how natural environmental perturbations influence subsurface microbial communities and associated biogeochemical processes. Over a six-month period we tracked the annual snowmelt-driven incursion of groundwater into the vadose zone of an aquifer adjacent to the Colorado River, leading to increased dissolved oxygen (DO) concentrations in the normally suboxic saturated zone. Strong biogeochemical heterogeneity was measured across the site, with abiotic reactions between DO and sulfide minerals driving rapid DO consumption and mobilization of redox active species in reduced aquifer regions. Conversely, extensive DO increases were detected in less reduced sediments. 16S rRNA gene surveys tracked microbial community composition within the aquifer, revealing strong correlations between increases in putative oxygen-utilizing chemolithoautotrophs and heterotrophs and rising DO concentrations. The gradual return to suboxic aquifer conditions favored increasing abundances of 16S rRNA sequences matching members of the Microgenomates (OP11) and Parcubacteria (OD1) that have been strongly implicated in fermentative processes. Microbial community stability measurements indicated that deeper aquifer locations were relatively less affected by geochemical perturbations, while communities in shallower locations exhibited the greatest change. Reactive transport modeling of the geochemical and microbiological results supported field observations, suggesting that a predictive framework can be applied to develop a greater understanding of such environments. Frontiers in Earth Science Journal Impact & Description - ResearchGate - Impact Rankings ( 2015 and 2016 ). Available from: https://www.researchgate.net/journal/2296-6463_Frontiers_in_Earth_Science [accessed Jul 25, 2016].
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- DOE Contract Number:
- AC05-76RL01830; AC02-05CH11231
- OSTI ID:
- 1342300
- Report Number(s):
- PNNL-SA-120170; 830403000
- Journal Information:
- Frontiers in Earth Science, Vol. 4; ISSN 2296-6463
- Publisher:
- Frontiers Research Foundation
- Country of Publication:
- United States
- Language:
- English
Impact of hydrologic boundaries on microbial planktonic and biofilm communities in shallow terrestrial subsurface environments
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journal | September 2018 |
Metatranscriptomic Analysis Reveals Unexpectedly Diverse Microbial Metabolism in a Biogeochemical Hot Spot in an Alluvial Aquifer
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journal | January 2017 |
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