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Zheng S, Liu M, Han Q, Pang L, Cao H. Seasonal variation and human impacts of the river biofilm bacterial communities in the Shiting River in southeastern China. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:341. [PMID: 38436747 DOI: 10.1007/s10661-024-12490-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Accepted: 02/19/2024] [Indexed: 03/05/2024]
Abstract
Bacterial communities in epilithic biofilm plays an important role in biogeochemistry processes in freshwater ecosystems. Nevertheless, our understanding of the geographical and seasonal variations of the composition of bacterial communities in the biofilm of gravels on river bed is still limited. Various anthropogenic activities also influence the biofilm bacteria in gravel rivers. By taking the Shiting River in the upper Yangtze River basin in Sichuan Province as an example, we studied the geographical and seasonal variations of epilithic bacteria and the impacts of weirs and other human activities (e.g., sewage pollution). The river has experienced severe degradation since the Ms 8.0 Wenchuan Earthquake, and weirs were constructed to prevent bed erosion. We collected epilithic biofilms samples at 17 sites along ~ 30 km river reach of the Shiting River in the autumn of 2021 and the summer of 2022, respectively. We applied 16S rRNA gene high-throughput sequencing technology and Functional Annotation of Prokaryotic Taxa (FAPROTAX) to analyze the seasonal and biogeographic patterns and potential functions of the biofilm bacterial communities. The results showed that epilithic bacteria from the two surveys exhibited variation in community composition, bacterial diversity and potential functions. The bacteria samples collected in the autumn have much higher alpha diversity and richness than those collected in the summer. Bacterial richness and diversity were lower downstream of the weirs than upstream. Low diversity was observed at a sampling site influenced by sewage inflow, which contains high level of nitrogen-related chemicals.
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Affiliation(s)
- Shan Zheng
- Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China, Earthquake Administration (Tianjin University), Tianjin, 300350, China.
- School of Civil Engineering, Tianjin University, Tianjin, 300350, China.
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China.
| | - Min Liu
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China
| | - Qinghua Han
- Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China, Earthquake Administration (Tianjin University), Tianjin, 300350, China
- School of Civil Engineering, Tianjin University, Tianjin, 300350, China
| | - Lina Pang
- College of Architecture and Environment, Sichuan University, Chengdu, 610065, China
| | - Huiqun Cao
- Changjiang River Scientific Research Institute, Wuhan, 430010, China
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Dong Y, Sanford RA, Connor L, Chee-Sanford J, Wimmer BT, Iranmanesh A, Shi L, Krapac IG, Locke RA, Shao H. Differential structure and functional gene response to geochemistry associated with the suspended and attached shallow aquifer microbiomes from the Illinois Basin, IL. WATER RESEARCH 2021; 202:117431. [PMID: 34320445 DOI: 10.1016/j.watres.2021.117431] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/05/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Despite the clear ecological significance of the microbiomes inhabiting groundwater and connected ecosystems, our current understanding of their habitats, functionality, and the ecological processes controlling their assembly have been limited. In this study, an efficient pipeline combining geochemistry, high-throughput FluidigmTM functional gene amplification and sequencing was developed to analyze the suspended and attached microbial communities inhabiting five groundwater monitoring wells in the Illinois Basin, USA. The dominant taxa in the suspended and the attached microbial communities exhibited significantly different spatial and temporal changes in both alpha- and beta-diversity. Further analyses of representative functional genes affiliated with N2 fixation (nifH), methane oxidation (pmoA), and sulfate reduction (dsrB, and aprA), suggested functional redundancy within the shallow aquifer microbiomes. While more diversified functional gene taxa were observed for the suspended microbial communities than the attached ones except for pmoA, different levels of changes over time and space were observed between these functional genes. Notably, deterministic and stochastic ecological processes shaped the assembly of microbial communities and functional gene reservoirs differently. While homogenous selection was the prevailing process controlling assembly of microbial communities, the neutral processes (e.g., dispersal limitation, drift and others) were more important for the functional genes. The results suggest complex and changing shallow aquifer microbiomes, whose functionality and assembly vary even between the spatially proximate habitats and fractions. This research underscored the importance to include all the interface components for a more holistic understanding of the biogeochemical processes in aquifer ecosystems, which is also instructive for practical applications.
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Affiliation(s)
- Yiran Dong
- School of Environmental Studies, China University of Geosciences, Wuhan, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
| | - Robert A Sanford
- Department of Geology, University of Illinois Urbana-Champaign, USA
| | | | | | | | | | - Liang Shi
- School of Environmental Studies, China University of Geosciences, Wuhan, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China
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Lui LM, Majumder ELW, Smith HJ, Carlson HK, von Netzer F, Fields MW, Stahl DA, Zhou J, Hazen TC, Baliga NS, Adams PD, Arkin AP. Mechanism Across Scales: A Holistic Modeling Framework Integrating Laboratory and Field Studies for Microbial Ecology. Front Microbiol 2021; 12:642422. [PMID: 33841364 PMCID: PMC8024649 DOI: 10.3389/fmicb.2021.642422] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Over the last century, leaps in technology for imaging, sampling, detection, high-throughput sequencing, and -omics analyses have revolutionized microbial ecology to enable rapid acquisition of extensive datasets for microbial communities across the ever-increasing temporal and spatial scales. The present challenge is capitalizing on our enhanced abilities of observation and integrating diverse data types from different scales, resolutions, and disciplines to reach a causal and mechanistic understanding of how microbial communities transform and respond to perturbations in the environment. This type of causal and mechanistic understanding will make predictions of microbial community behavior more robust and actionable in addressing microbially mediated global problems. To discern drivers of microbial community assembly and function, we recognize the need for a conceptual, quantitative framework that connects measurements of genomic potential, the environment, and ecological and physical forces to rates of microbial growth at specific locations. We describe the Framework for Integrated, Conceptual, and Systematic Microbial Ecology (FICSME), an experimental design framework for conducting process-focused microbial ecology studies that incorporates biological, chemical, and physical drivers of a microbial system into a conceptual model. Through iterative cycles that advance our understanding of the coupling across scales and processes, we can reliably predict how perturbations to microbial systems impact ecosystem-scale processes or vice versa. We describe an approach and potential applications for using the FICSME to elucidate the mechanisms of globally important ecological and physical processes, toward attaining the goal of predicting the structure and function of microbial communities in chemically complex natural environments.
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Affiliation(s)
- Lauren M. Lui
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Erica L.-W. Majumder
- Department of Bacteriology, University of Wisconsin–Madison, Madison, WI, United States
| | - Heidi J. Smith
- Center for Biofilm Engineering, Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - Hans K. Carlson
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Frederick von Netzer
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, United States
| | - Matthew W. Fields
- Center for Biofilm Engineering, Department of Microbiology and Immunology, Montana State University, Bozeman, MT, United States
| | - David A. Stahl
- Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, United States
| | - Jizhong Zhou
- Institute for Environmental Genomics, Department of Microbiology & Plant Biology, School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, OK, United States
| | - Terry C. Hazen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, Knoxville, TN, United States
| | | | - Paul D. Adams
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Adam P. Arkin
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
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In-field bioreactors demonstrate dynamic shifts in microbial communities in response to geochemical perturbations. PLoS One 2020; 15:e0232437. [PMID: 32986713 PMCID: PMC7521895 DOI: 10.1371/journal.pone.0232437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 09/09/2020] [Indexed: 11/19/2022] Open
Abstract
Subsurface microbial communities mediate the transformation and fate of redox sensitive materials including organic matter, metals and radionuclides. Few studies have explored how changing geochemical conditions influence the composition of groundwater microbial communities over time. We temporally monitored alterations in abiotic forces on microbial community structure using 1L in-field bioreactors receiving background and contaminated groundwater at the Oak Ridge Reservation, TN. Planktonic and biofilm microbial communities were initialized with background water for 4 days to establish communities in triplicate control reactors and triplicate test reactors and then fed filtered water for 14 days. On day 18, three reactors were switched to receive filtered groundwater from a contaminated well, enriched in total dissolved solids relative to the background site, particularly chloride, nitrate, uranium, and sulfate. Biological and geochemical data were collected throughout the experiment, including planktonic and biofilm DNA for 16S rRNA amplicon sequencing, cell counts, total protein, anions, cations, trace metals, organic acids, bicarbonate, pH, Eh, DO, and conductivity. We observed significant shifts in both planktonic and biofilm microbial communities receiving contaminated water. This included a loss of rare taxa, especially amongst members of the Bacteroidetes, Acidobacteria, Chloroflexi, and Betaproteobacteria, but enrichment in the Fe- and nitrate- reducing Ferribacterium and parasitic Bdellovibrio. These shifted communities were more similar to the contaminated well community, suggesting that geochemical forces substantially influence microbial community diversity and structure. These influences can only be captured through such comprehensive temporal studies, which also enable more robust and accurate predictive models to be developed.
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Moon JW, Paradis CJ, Joyner DC, von Netzer F, Majumder EL, Dixon ER, Podar M, Ge X, Walian PJ, Smith HJ, Wu X, Zane GM, Walker KF, Thorgersen MP, Poole Ii FL, Lui LM, Adams BG, De León KB, Brewer SS, Williams DE, Lowe KA, Rodriguez M, Mehlhorn TL, Pfiffner SM, Chakraborty R, Arkin AP, Wall JD, Fields MW, Adams MWW, Stahl DA, Elias DA, Hazen TC. Characterization of subsurface media from locations up- and down-gradient of a uranium-contaminated aquifer. CHEMOSPHERE 2020; 255:126951. [PMID: 32417512 DOI: 10.1016/j.chemosphere.2020.126951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 04/17/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
The processing of sediment to accurately characterize the spatially-resolved depth profiles of geophysical and geochemical properties along with signatures of microbial density and activity remains a challenge especially in complex contaminated areas. This study processed cores from two sediment boreholes from background and contaminated core sediments and surrounding groundwater. Fresh core sediments were compared by depth to capture the changes in sediment structure, sediment minerals, biomass, and pore water geochemistry in terms of major and trace elements including pollutants, cations, anions, and organic acids. Soil porewater samples were matched to groundwater level, flow rate, and preferential flows and compared to homogenized groundwater-only samples from neighboring monitoring wells. Groundwater analysis of nearby wells only revealed high sulfate and nitrate concentrations while the same analysis using sediment pore water samples with depth was able to suggest areas high in sulfate- and nitrate-reducing bacteria based on their decreased concentration and production of reduced by-products that could not be seen in the groundwater samples. Positive correlations among porewater content, total organic carbon, trace metals and clay minerals revealed a more complicated relationship among contaminant, sediment texture, groundwater table, and biomass. The fluctuating capillary interface had high concentrations of Fe and Mn-oxides combined with trace elements including U, Th, Sr, Ba, Cu, and Co. This suggests the mobility of potentially hazardous elements, sediment structure, and biogeochemical factors are all linked together to impact microbial communities, emphasizing that solid interfaces play an important role in determining the abundance of bacteria in the sediments.
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Affiliation(s)
- Ji-Won Moon
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, USA; current U.S. Geological Survey, National Minerals Information Center, Reston, VA, USA
| | - Charles J Paradis
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Dominique C Joyner
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Frederick von Netzer
- University of Washington, Department of Civil and Environmental Engineering, Seattle, WA, USA
| | - Erica L Majumder
- University of Missouri, Department of Biochemistry, Columbia, MO, USA
| | - Emma R Dixon
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Mircea Podar
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, USA
| | - Xiaoxuan Ge
- University of Georgia, Department of Biochemistry and Molecular Biology, Athens, GA, USA
| | - Peter J Walian
- Lawrence Berkeley National Laboratory, Molecular Biophysics and Integrated Bioimaging, Berkeley, CA, USA
| | - Heidi J Smith
- Montana State University, Center for Biofilm Engineering, Department of Microbiology & Immunology, Bozeman, MT, USA
| | - Xiaoqin Wu
- Lawrence Berkeley National Laboratory, Department of Ecology, Earth and Environmental Sciences Area, Berkeley, CA, USA
| | - Grant M Zane
- University of Missouri, Department of Biochemistry, Columbia, MO, USA
| | - Kathleen F Walker
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Michael P Thorgersen
- University of Georgia, Department of Biochemistry and Molecular Biology, Athens, GA, USA
| | - Farris L Poole Ii
- University of Georgia, Department of Biochemistry and Molecular Biology, Athens, GA, USA
| | - Lauren M Lui
- Lawrence Berkeley National Laboratory Environmental Genomics and Systems Biology, Berkeley, CA, USA
| | - Benjamin G Adams
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Kara B De León
- University of Missouri, Department of Biochemistry, Columbia, MO, USA
| | - Sheridan S Brewer
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Daniel E Williams
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Kenneth A Lowe
- Oak Ridge National Laboratory, Environmental Science Division, Oak Ridge, TN, USA
| | - Miguel Rodriguez
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, USA
| | - Tonia L Mehlhorn
- Oak Ridge National Laboratory, Environmental Science Division, Oak Ridge, TN, USA
| | - Susan M Pfiffner
- University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA
| | - Romy Chakraborty
- Lawrence Berkeley National Laboratory, Department of Ecology, Earth and Environmental Sciences Area, Berkeley, CA, USA
| | - Adam P Arkin
- Lawrence Berkeley National Laboratory Environmental Genomics and Systems Biology, Berkeley, CA, USA
| | - Judy D Wall
- University of Missouri, Department of Biochemistry, Columbia, MO, USA
| | - Matthew W Fields
- Montana State University, Center for Biofilm Engineering, Department of Microbiology & Immunology, Bozeman, MT, USA
| | - Michael W W Adams
- University of Georgia, Department of Biochemistry and Molecular Biology, Athens, GA, USA
| | - David A Stahl
- University of Washington, Department of Civil and Environmental Engineering, Seattle, WA, USA
| | - Dwayne A Elias
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, USA
| | - Terry C Hazen
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, USA; University of Tennessee, Departments of Earth & Planetary Sciences, Microbiology, Civil & Environmental Engineering, Methane Center, Knoxville, TN, USA.
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Christensen GA, Gionfriddo CM, King AJ, Moberly JG, Miller CL, Somenahally AC, Callister SJ, Brewer H, Podar M, Brown SD, Palumbo AV, Brandt CC, Wymore AM, Brooks SC, Hwang C, Fields MW, Wall JD, Gilmour CC, Elias DA. Determining the Reliability of Measuring Mercury Cycling Gene Abundance with Correlations with Mercury and Methylmercury Concentrations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8649-8663. [PMID: 31260289 DOI: 10.1021/acs.est.8b06389] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Methylmercury (MeHg) is a bioaccumulative toxic contaminant in many ecosystems, but factors governing its production are poorly understood. Recent work has shown that the anaerobic microbial conversion of mercury (Hg) to MeHg requires the Hg-methylation genes hgcAB and that these genes can be used as biomarkers in PCR-based estimators of Hg-methylator abundance. In an effort to determine reliable methods for assessing hgcA abundance and diversity and linking them to MeHg concentrations, multiple approaches were compared including metagenomic shotgun sequencing, 16S rRNA gene pyrosequencing and cloning/sequencing hgcAB gene products. Hg-methylator abundance was also determined by quantitative hgcA qPCR amplification and metaproteomics for comparison to the above measurements. Samples from eight sites were examined covering a range of total Hg (HgT; 0.03-14 mg kg-1 dry wt. soil) and MeHg (0.05-27 μg kg-1 dry wt. soil) concentrations. In the metagenome and amplicon sequencing of hgcAB diversity, the Deltaproteobacteria were the dominant Hg-methylators while Firmicutes and methanogenic Archaea were typically ∼50% less abundant. This was consistent with metaproteomics estimates where the Deltaproteobacteria were steadily higher. The 16S rRNA gene pyrosequencing did not have sufficient resolution to identify hgcAB+ species. Metagenomic and hgcAB results were similar for Hg-methylator diversity and clade-specific qPCR-based approaches for hgcA are only appropriate when comparing the abundance of a particular clade across various samples. Weak correlations between Hg-methylating bacteria and soil Hg concentrations were observed for similar environmental samples, but overall total Hg and MeHg concentrations poorly correlated with Hg-cycling genes.
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Affiliation(s)
- Geoff A Christensen
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Caitlin M Gionfriddo
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Andrew J King
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - James G Moberly
- College of Engineering , University of Idaho , Moscow , Idaho 83844 , United States
| | - Carrie L Miller
- School of Theoretical and Applied Science , Ramapo College of New Jersey , Mahwah , New Jersey 07430 , United States
| | - Anil C Somenahally
- Department of Soil and Crop Sciences , Texas A&M University , Overton , Texas 77843-2474 , United States
| | - Stephen J Callister
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Heather Brewer
- Biological Sciences Division , Pacific Northwest National Laboratory , Richland , Washington 99352 , United States
| | - Mircea Podar
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Steven D Brown
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Anthony V Palumbo
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Craig C Brandt
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Ann M Wymore
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
| | - Scott C Brooks
- Environmental Sciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Chiachi Hwang
- Center for Biofilm Engineering , Montana State University , Bozeman , Montana 59717 , United States
| | - Matthew W Fields
- Department of Microbiology and Immunology , Montana State University , Bozeman , Montana 59717 , United States
- Center for Biofilm Engineering , Montana State University , Bozeman , Montana 59717 , United States
| | - Judy D Wall
- Department of Biochemistry , University of Missouri , Columbia , Missouri 65211 , United States
| | - Cynthia C Gilmour
- Smithsonian Environmental Research Center , Edgewater , Maryland 21037 , United States
| | - Dwayne A Elias
- Biosciences Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6342 , United States
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7
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Smith HJ, Zelaya AJ, De León KB, Chakraborty R, Elias DA, Hazen TC, Arkin AP, Cunningham AB, Fields MW. Impact of hydrologic boundaries on microbial planktonic and biofilm communities in shallow terrestrial subsurface environments. FEMS Microbiol Ecol 2018; 94:5107865. [PMID: 30265315 PMCID: PMC6192502 DOI: 10.1093/femsec/fiy191] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/26/2018] [Indexed: 12/12/2022] Open
Abstract
Subsurface environments contain a large proportion of planetary microbial biomass and harbor diverse communities responsible for mediating biogeochemical cycles important to groundwater used by human society for consumption, irrigation, agriculture and industry. Within the saturated zone, capillary fringe and vadose zones, microorganisms can reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the contribution of each phase to subsurface processes is largely unresolved. Here, we synthesize current information on the diversity and activity of shallow freshwater subsurface habitats, discuss the challenges associated with sampling planktonic and biofilm communities across spatial, temporal and geological gradients, and discuss how biofilms may be constrained within shallow terrestrial subsurface aquifers. We suggest that merging traditional activity measurements and sequencing/-omics technologies with hydrological parameters important to sediment biofilm assembly and stability will help delineate key system parameters. Ultimately, integration will enhance our understanding of shallow subsurface ecophysiology in terms of bulk-flow through porous media and distinguish the respective activities of sessile microbial communities from more transient planktonic communities to ecosystem service and maintenance.
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Affiliation(s)
- H J Smith
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - A J Zelaya
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - K B De León
- Department of Biochemistry, University of Missouri, Columbia, MO
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - R Chakraborty
- Climate and Ecosystems Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - D A Elias
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - T C Hazen
- Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - A P Arkin
- Department of Bioengineering, Lawrence Berkeley National Laboratory, Berkeley, CA
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
| | - A B Cunningham
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- Department of Civil Engineering, Montana State University, Montana State University, Bozeman, MT
| | - M W Fields
- Center for Biofilm Engineering, Montana State University, Bozeman, MT
- Department of Microbiology & Immunology, Montana State University, Bozeman, MT
- ENIGMA (www.enigma.lbl.gov) Environmental Genomics and Systems Biology Division, Biosciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS:977, Berkeley, CA 94720
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