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Coskun ÖK, Gomez-Saez GV, Beren M, Özcan D, Günay SD, Elkin V, Hoşgörmez H, Einsiedl F, Eisenreich W, Orsi WD. Quantifying genome-specific carbon fixation in a 750-meter deep subsurface hydrothermal microbial community. FEMS Microbiol Ecol 2024; 100:fiae062. [PMID: 38632042 DOI: 10.1093/femsec/fiae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/16/2024] [Accepted: 04/16/2024] [Indexed: 04/19/2024] Open
Abstract
Dissolved inorganic carbon has been hypothesized to stimulate microbial chemoautotrophic activity as a biological sink in the carbon cycle of deep subsurface environments. Here, we tested this hypothesis using quantitative DNA stable isotope probing of metagenome-assembled genomes (MAGs) at multiple 13C-labeled bicarbonate concentrations in hydrothermal fluids from a 750-m deep subsurface aquifer in the Biga Peninsula (Turkey). The diversity of microbial populations assimilating 13C-labeled bicarbonate was significantly different at higher bicarbonate concentrations, and could be linked to four separate carbon-fixation pathways encoded within 13C-labeled MAGs. Microbial populations encoding the Calvin-Benson-Bassham cycle had the highest contribution to carbon fixation across all bicarbonate concentrations tested, spanning 1-10 mM. However, out of all the active carbon-fixation pathways detected, MAGs affiliated with the phylum Aquificae encoding the reverse tricarboxylic acid (rTCA) pathway were the only microbial populations that exhibited an increased 13C-bicarbonate assimilation under increasing bicarbonate concentrations. Our study provides the first experimental data supporting predictions that increased bicarbonate concentrations may promote chemoautotrophy via the rTCA cycle and its biological sink for deep subsurface inorganic carbon.
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Affiliation(s)
- Ömer K Coskun
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Richard-Wagner Straße 10, 80333 Munich, Germany
| | - Gonzalo V Gomez-Saez
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Richard-Wagner Straße 10, 80333 Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner Straße 10, 80333 Munich, Germany
| | - Murat Beren
- Department of Geological Engineering, Istanbul University - Cerrahpasa, Büyükçekmece Campus, Block G, Floor 5, Istanbul, Turkey
| | - Doğacan Özcan
- Department of Geological Engineering, Istanbul University - Cerrahpasa, Büyükçekmece Campus, Block G, Floor 5, Istanbul, Turkey
| | - Suna D Günay
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Richard-Wagner Straße 10, 80333 Munich, Germany
| | - Viktor Elkin
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Richard-Wagner Straße 10, 80333 Munich, Germany
| | - Hakan Hoşgörmez
- Department of Geological Engineering, Istanbul University - Cerrahpasa, Büyükçekmece Campus, Block G, Floor 5, Istanbul, Turkey
| | - Florian Einsiedl
- Chair of Hydrogeology, School of Engineering and Design, Technical University Munich, Arcisstraße 21, 80333 Munich, Germany
| | - Wolfgang Eisenreich
- Lehrstuhl für Biochemie, Department Chemie, Technische Universität München, Lichtenbergstraße, 85748 Garching, Germany
| | - William D Orsi
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Richard-Wagner Straße 10, 80333 Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner Straße 10, 80333 Munich, Germany
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2
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Kostešić E, Mitrović M, Kajan K, Marković T, Hausmann B, Orlić S, Pjevac P. Microbial Diversity and Activity of Biofilms from Geothermal Springs in Croatia. MICROBIAL ECOLOGY 2023; 86:2305-2319. [PMID: 37209180 PMCID: PMC10640420 DOI: 10.1007/s00248-023-02239-1] [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: 03/03/2023] [Accepted: 05/07/2023] [Indexed: 05/22/2023]
Abstract
Hot spring biofilms are stable, highly complex microbial structures. They form at dynamic redox and light gradients and are composed of microorganisms adapted to the extreme temperatures and fluctuating geochemical conditions of geothermal environments. In Croatia, a large number of poorly investigated geothermal springs host biofilm communities. Here, we investigated the microbial community composition of biofilms collected over several seasons at 12 geothermal springs and wells. We found biofilm microbial communities to be temporally stable and highly dominated by Cyanobacteria in all but one high-temperature sampling site (Bizovac well). Of the physiochemical parameters recorded, temperature had the strongest influence on biofilm microbial community composition. Besides Cyanobacteria, the biofilms were mainly inhabited by Chloroflexota, Gammaproteobacteria, and Bacteroidota. In a series of incubations with Cyanobacteria-dominated biofilms from Tuhelj spring and Chloroflexota- and Pseudomonadota-dominated biofilms from Bizovac well, we stimulated either chemoorganotrophic or chemolithotrophic community members, to determine the fraction of microorganisms dependent on organic carbon (in situ predominantly produced via photosynthesis) versus energy derived from geochemical redox gradients (here simulated by addition of thiosulfate). We found surprisingly similar levels of activity in response to all substrates in these two distinct biofilm communities, and observed microbial community composition and hot spring geochemistry to be poor predictors of microbial activity in the study systems.
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Affiliation(s)
- Ema Kostešić
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Maja Mitrović
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Katarina Kajan
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
- Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia
| | | | - Bela Hausmann
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Sandi Orlić
- Division of Materials Chemistry, Ruđer Bošković Institute, Zagreb, Croatia
- Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia
| | - Petra Pjevac
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Vienna, Austria.
- Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria.
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3
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Lai D, Hedlund BP, Mau RL, Jiao JY, Li J, Hayer M, Dijkstra P, Schwartz E, Li WJ, Dong H, Palmer M, Dodsworth JA, Zhou EM, Hungate BA. Resource partitioning and amino acid assimilation in a terrestrial geothermal spring. THE ISME JOURNAL 2023; 17:2112-2122. [PMID: 37741957 PMCID: PMC10579274 DOI: 10.1038/s41396-023-01517-7] [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: 05/24/2023] [Revised: 08/31/2023] [Accepted: 09/13/2023] [Indexed: 09/25/2023]
Abstract
High-temperature geothermal springs host simplified microbial communities; however, the activities of individual microorganisms and their roles in the carbon cycle in nature are not well understood. Here, quantitative stable isotope probing (qSIP) was used to track the assimilation of 13C-acetate and 13C-aspartate into DNA in 74 °C sediments in Gongxiaoshe Hot Spring, Tengchong, China. This revealed a community-wide preference for aspartate and a tight coupling between aspartate incorporation into DNA and the proliferation of aspartate utilizers during labeling. Both 13C incorporation into DNA and changes in the abundance of taxa during incubations indicated strong resource partitioning and a significant phylogenetic signal for aspartate incorporation. Of the active amplicon sequence variants (ASVs) identified by qSIP, most could be matched with genomes from Gongxiaoshe Hot Spring or nearby springs with an average nucleotide similarity of 99.4%. Genomes corresponding to aspartate primary utilizers were smaller, near-universally encoded polar amino acid ABC transporters, and had codon preferences indicative of faster growth rates. The most active ASVs assimilating both substrates were not abundant, suggesting an important role for the rare biosphere in the community response to organic carbon addition. The broad incorporation of aspartate into DNA over acetate by the hot spring community may reflect dynamic cycling of cell lysis products in situ or substrates delivered during monsoon rains and may reflect N limitation.
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Affiliation(s)
- Dengxun Lai
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA.
- Nevada Institute for Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, USA.
| | - Rebecca L Mau
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Jian-Yu Jiao
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Junhui Li
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Michaela Hayer
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Hailiang Dong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China and Department of Geology and Environmental Earth Science, Miami University, Oxford, OH, USA
| | - Marike Palmer
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Jeremy A Dodsworth
- Department of Biology, California State University, San Bernardino, CA, USA
| | - En-Min Zhou
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
- School of Resource Environment and Earth Science, Yunnan University, Kunming, China
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
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Millette NC, Gast RJ, Luo JY, Moeller HV, Stamieszkin K, Andersen KH, Brownlee EF, Cohen NR, Duhamel S, Dutkiewicz S, Glibert PM, Johnson MD, Leles SG, Maloney AE, Mcmanus GB, Poulton N, Princiotta SD, Sanders RW, Wilken S. Mixoplankton and mixotrophy: future research priorities. JOURNAL OF PLANKTON RESEARCH 2023; 45:576-596. [PMID: 37483910 PMCID: PMC10361813 DOI: 10.1093/plankt/fbad020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/14/2023] [Indexed: 07/25/2023]
Abstract
Phago-mixotrophy, the combination of photoautotrophy and phagotrophy in mixoplankton, organisms that can combine both trophic strategies, have gained increasing attention over the past decade. It is now recognized that a substantial number of protistan plankton species engage in phago-mixotrophy to obtain nutrients for growth and reproduction under a range of environmental conditions. Unfortunately, our current understanding of mixoplankton in aquatic systems significantly lags behind our understanding of zooplankton and phytoplankton, limiting our ability to fully comprehend the role of mixoplankton (and phago-mixotrophy) in the plankton food web and biogeochemical cycling. Here, we put forward five research directions that we believe will lead to major advancement in the field: (i) evolution: understanding mixotrophy in the context of the evolutionary transition from phagotrophy to photoautotrophy; (ii) traits and trade-offs: identifying the key traits and trade-offs constraining mixotrophic metabolisms; (iii) biogeography: large-scale patterns of mixoplankton distribution; (iv) biogeochemistry and trophic transfer: understanding mixoplankton as conduits of nutrients and energy; and (v) in situ methods: improving the identification of in situ mixoplankton and their phago-mixotrophic activity.
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Affiliation(s)
| | - Rebecca J Gast
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Jessica Y Luo
- NOAA Geophysical Fluid Dynamics Laboratory, 201 Forrestal Rd., Princeton, NJ 08540, USA
| | - Holly V Moeller
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, 1120 Noble Hall, Santa Barbara, CA 93106, USA
| | - Karen Stamieszkin
- Bigelow Laboratory for Ocean Sciences, 60 Bigelow Dr., East Boothbay, ME 04544, USA
| | - Ken H Andersen
- Center for Ocean Life, Natl. Inst. of Aquatic Resources, Technical University of Denmark, Kemitorvet, Bygning 202, Kongens Lyngby 2840, Denmark
| | - Emily F Brownlee
- Department of Biology, St. Mary’s College of Maryland, 18952 E. Fisher Road, St. Mary’s City, MD 20686, USA
| | - Natalie R Cohen
- Skidaway Institute of Oceanography, University of Georgia, 10 Ocean Science Circle, Savannah, GA 31411, USA
| | - Solange Duhamel
- Department of Molecular and Cellular Biology, The University of Arizona, 1007 E Lowell Street, Tucson, AZ 85721, USA
| | - Stephanie Dutkiewicz
- Center for Global Change Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02874, USA
| | - Patricia M Glibert
- Horn Point Laboratory, University of Maryland Center for Environmental Science, 2020 Horns Point Rd, Cambridge, MD 21613, USA
| | - Matthew D Johnson
- Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Suzana G Leles
- Department of Marine and Environmental Biology, University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA 90089, USA
| | - Ashley E Maloney
- Geosciences Department, Princeton University, Guyot Hall, Princeton, NJ 08544, USA
| | - George B Mcmanus
- Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Rd., Groton, CT 06340, USA
| | - Nicole Poulton
- Bigelow Laboratory for Ocean Sciences, 60 Bigelow Dr., East Boothbay, ME 04544, USA
| | - Sarah D Princiotta
- Biology Department, Pennsylvania State University, Schuylkill Campus, 200 University Drive, Schuylkill Haven, PA 17972, USA
| | - Robert W Sanders
- Department of Biology, Temple University, 1900 N. 12th St., Philadelphia, PA 19122, USA
| | - Susanne Wilken
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, The Netherlands
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5
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Moran JJ, Bernstein HC, Mobberley JM, Thompson AM, Kim YM, Dana KL, Cory AB, Courtney S, Renslow RS, Fredrickson JK, Kreuzer HW, Lipton MS. Daylight-driven carbon exchange through a vertically structured microbial community. Front Microbiol 2023; 14:1139213. [PMID: 37303779 PMCID: PMC10251406 DOI: 10.3389/fmicb.2023.1139213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Interactions between autotrophs and heterotrophs are central to carbon (C) exchange across trophic levels in essentially all ecosystems and metabolite exchange is a frequent mechanism for distributing C within spatially structured ecosystems. Yet, despite the importance of C exchange, the timescales at which fixed C is transferred in microbial communities is poorly understood. We employed a stable isotope tracer combined with spatially resolved isotope analysis to quantify photoautotrophic uptake of bicarbonate and track subsequent exchanges across a vertical depth gradient in a stratified microbial mat over a light-driven diel cycle. We observed that C mobility, both across the vertical strata and between taxa, was highest during periods of active photoautotrophy. Parallel experiments with 13C-labeled organic substrates (acetate and glucose) showed comparably less exchange of C within the mat. Metabolite analysis showed rapid incorporation of 13C into molecules that can both comprise a portion of the extracellular polymeric substances in the system and serve to transport C between photoautotrophs and heterotrophs. Stable isotope proteomic analysis revealed rapid C exchange between cyanobacterial and associated heterotrophic community members during the day with decreased exchange at night. We observed strong diel control on the spatial exchange of freshly fixed C within tightly interacting mat communities suggesting a rapid redistribution, both spatially and taxonomically, primarily during daylight periods.
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Affiliation(s)
- James J. Moran
- Pacific Northwest National Laboratory, Richland, WA, United States
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
- Department of Plant, Soil, and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - Hans C. Bernstein
- Pacific Northwest National Laboratory, Richland, WA, United States
- Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- ARC – The Arctic Centre for Sustainable Energy, UiT The Arctic University of Norway, Tromsø, Norway
| | | | | | - Young-Mo Kim
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Karl L. Dana
- Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Steph Courtney
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Ryan S. Renslow
- Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Helen W. Kreuzer
- Pacific Northwest National Laboratory, Richland, WA, United States
| | - Mary S. Lipton
- Pacific Northwest National Laboratory, Richland, WA, United States
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6
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Ecological Dichotomies Arise in Microbial Communities Due to Mixing of Deep Hydrothermal Waters and Atmospheric Gas in a Circumneutral Hot Spring. Appl Environ Microbiol 2021; 87:e0159821. [PMID: 34586901 PMCID: PMC8579995 DOI: 10.1128/aem.01598-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little is known of how the confluence of subsurface and surface processes influences the assembly and habitability of hydrothermal ecosystems. To address this knowledge gap, the geochemical and microbial composition of a high-temperature, circumneutral hot spring in Yellowstone National Park was examined to identify the sources of solutes and their effect on the ecology of microbial inhabitants. Metagenomic analysis showed that populations comprising planktonic and sediment communities are archaeal dominated, are dependent on chemical energy (chemosynthetic), share little overlap in their taxonomic composition, and are differentiated by their inferred use of/tolerance to oxygen and mode of carbon metabolism. The planktonic community is dominated by putative aerobic/aerotolerant autotrophs, while the taxonomic composition of the sediment community is more evenly distributed and comprised of anaerobic heterotrophs. These observations are interpreted to reflect sourcing of the spring by anoxic, organic carbon-limited subsurface hydrothermal fluids and ingassing of atmospheric oxygen that selects for aerobic/aerotolerant organisms that have autotrophic capabilities in the water column. Autotrophy and consumption of oxygen by the planktonic community may influence the assembly of the anaerobic and heterotrophic sediment community. Support for this inference comes from higher estimated rates of genome replication in planktonic populations than sediment populations, indicating faster growth in planktonic populations. Collectively, these observations provide new insight into how mixing of subsurface waters and atmospheric oxygen create dichotomy in the ecology of hot spring communities and suggest that planktonic and sediment communities may have been less differentiated taxonomically and functionally prior to the rise of oxygen at ∼2.4 billion years ago (Gya). IMPORTANCE Understanding the source and availability of energy capable of supporting life in hydrothermal environments is central to predicting the ecology of microbial life on early Earth when volcanic activity was more widespread. Little is known of the substrates supporting microbial life in circumneutral to alkaline springs, despite their relevance to early Earth habitats. Using metagenomic and informatics approaches, water column and sediment habitats in a representative circumneutral hot spring in Yellowstone were shown to be dichotomous, with the former largely hosting aerobic/aerotolerant autotrophs and the latter primarily hosting anaerobic heterotrophs. This dichotomy is attributed to influx of atmospheric oxygen into anoxic deep hydrothermal spring waters. These results indicate that the ecology of microorganisms in circumneutral alkaline springs sourced by deep hydrothermal fluids was different prior to the rise of atmospheric oxygen ∼2.4 Gya, with planktonic and sediment communities likely to be less differentiated than contemporary circumneutral hot springs.
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Stable-Isotope-Informed, Genome-Resolved Metagenomics Uncovers Potential Cross-Kingdom Interactions in Rhizosphere Soil. mSphere 2021; 6:e0008521. [PMID: 34468166 PMCID: PMC8550312 DOI: 10.1128/msphere.00085-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The functioning, health, and productivity of soil are intimately tied to a complex network of interactions, particularly in plant root-associated rhizosphere soil. We conducted a stable-isotope-informed, genome-resolved metagenomic study to trace carbon from Avena fatua grown in a 13CO2 atmosphere into soil. We collected paired rhizosphere and nonrhizosphere soil at 6 and 9 weeks of plant growth and extracted DNA that was then separated by density using ultracentrifugation. Thirty-two fractions from each of five samples were grouped by density, sequenced, assembled, and binned to generate 55 unique bacterial genomes that were ≥70% complete. We also identified complete 18S rRNA sequences of several 13C-enriched microeukaryotic bacterivores and fungi. We generated 10 circularized bacteriophage (phage) genomes, some of which were the most labeled entities in the rhizosphere, suggesting that phage may be important agents of turnover of plant-derived C in soil. CRISPR locus targeting connected one of these phage to a Burkholderiales host predicted to be a plant pathogen. Another highly labeled phage is predicted to replicate in a Catenulispora sp., a possible plant growth-promoting bacterium. We searched the genome bins for traits known to be used in interactions involving bacteria, microeukaryotes, and plant roots and found DNA from heavily 13C-labeled bacterial genes thought to be involved in modulating plant signaling hormones, plant pathogenicity, and defense against microeukaryote grazing. Stable-isotope-informed, genome-resolved metagenomics indicated that phage can be important agents of turnover of plant-derived carbon in soil. IMPORTANCE Plants grow in intimate association with soil microbial communities; these microbes can facilitate the availability of essential resources to plants. Thus, plant productivity commonly depends on interactions with rhizosphere bacteria, viruses, and eukaryotes. Our work is significant because we identified the organisms that took up plant-derived organic C in rhizosphere soil and determined that many of the active bacteria are plant pathogens or can impact plant growth via hormone modulation. Further, by showing that bacteriophage accumulate CO2-derived carbon, we demonstrated their vital roles in redistribution of plant-derived C into the soil environment through bacterial cell lysis. The use of stable-isotope probing (SIP) to identify consumption (or lack thereof) of root-derived C by key microbial community members within highly complex microbial communities opens the way for assessing manipulations of bacteria and phage with potentially beneficial and detrimental traits, ultimately providing a path to improved plant health and soil carbon storage.
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Coskun ÖK, Vuillemin A, Schubotz F, Klein F, Sichel SE, Eisenreich W, Orsi WD. Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. ISME JOURNAL 2021; 16:257-271. [PMID: 34312482 PMCID: PMC8692406 DOI: 10.1038/s41396-021-01066-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 07/05/2021] [Accepted: 07/09/2021] [Indexed: 11/09/2022]
Abstract
Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.
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Affiliation(s)
- Ömer K Coskun
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany
| | - Aurèle Vuillemin
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany.,GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Potsdam, Germany
| | - Florence Schubotz
- MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Frieder Klein
- Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Susanna E Sichel
- Departamento de Geologia e Geofísica/LAGEMAR-Universidade Federal Fluminense-Brazil, Niterói, RJ, Brazil
| | - Wolfgang Eisenreich
- Department of Chemistry, Bavarian NMR Center-Structural Membrane Biochemistry, Technische Universität München, Garching, Germany
| | - William D Orsi
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany. .,GeoBio-CenterLMU, Ludwig-Maximilians-Universität München, Munich, Germany.
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9
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Mueller RC, Peach JT, Skorupa DJ, Copié V, Bothner B, Peyton BM. An emerging view of the diversity, ecology and function of Archaea in alkaline hydrothermal environments. FEMS Microbiol Ecol 2021; 97:6021323. [PMID: 33501490 DOI: 10.1093/femsec/fiaa246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 12/01/2020] [Indexed: 11/15/2022] Open
Abstract
The described diversity within the domain Archaea has recently expanded due to advances in sequencing technologies, but many habitats that likely harbor novel lineages of archaea remain understudied. Knowledge of archaea within natural and engineered hydrothermal systems, such as hot springs and engineered subsurface habitats, has been steadily increasing, but the majority of the work has focused on archaea living in acidic or circumneutral environments. The environmental pressures exerted by the combination of high temperatures and high pH likely select for divergent communities and distinct metabolic pathways from those observed in acidic or circumneutral systems. In this review, we examine what is currently known about the archaea found in thermoalkaline environments, focusing on the detection of novel lineages and knowledge of the ecology, metabolic pathways and functions of these populations and communities. We also discuss the potential of emerging multi-omics approaches, including proteomics and metabolomics, to enhance our understanding of archaea within extreme thermoalkaline systems.
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Affiliation(s)
- Rebecca C Mueller
- Department of Chemical and Biological Engineering, Montana State University,Bozeman, MT 59717, PO Box 173920, USA.,Thermal Biology Institute, Montana State University, Bozeman, MT 59717, PO Box 173142, USA
| | - Jesse T Peach
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, PO Box 173400, USA
| | - Dana J Skorupa
- Department of Chemical and Biological Engineering, Montana State University,Bozeman, MT 59717, PO Box 173920, USA.,Thermal Biology Institute, Montana State University, Bozeman, MT 59717, PO Box 173142, USA
| | - Valerie Copié
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, PO Box 173400, USA.,Thermal Biology Institute, Montana State University, Bozeman, MT 59717, PO Box 173142, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, PO Box 173400, USA.,Thermal Biology Institute, Montana State University, Bozeman, MT 59717, PO Box 173142, USA
| | - Brent M Peyton
- Department of Chemical and Biological Engineering, Montana State University,Bozeman, MT 59717, PO Box 173920, USA.,Thermal Biology Institute, Montana State University, Bozeman, MT 59717, PO Box 173142, USA
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10
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Wörmer L, Gajendra N, Schubotz F, Matys ED, Evans TW, Summons RE, Hinrichs KU. A micrometer-scale snapshot on phototroph spatial distributions: mass spectrometry imaging of microbial mats in Octopus Spring, Yellowstone National Park. GEOBIOLOGY 2020; 18:742-759. [PMID: 32936514 DOI: 10.1111/gbi.12411] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 07/10/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Microbial mats from alkaline hot springs in the Yellowstone National Park are ideal natural laboratories to study photosynthetic life under extreme conditions, as well as the nuanced interactions of oxygenic and anoxygenic phototrophs. They represent distinctive examples of chlorophototroph (i.e., chlorophyll or bacteriochlorophyll-based phototroph) diversity, and several novel phototrophs have been first described in these systems, all confined in space, coexisting and competing for niches defined by parameters such as light, oxygen, or temperature. In a novel approach, we employed mass spectrometry imaging of chloropigments, quinones, and intact polar lipids (IPLs) to describe the spatial distribution of different groups of chlorophototrophs along the ~ 1 cm thick microbial mat at 75 µm resolution and in the top ~ 1.5 mm green part of the mat at 25 µm resolution. We observed a fine-tuned sequence of oxygenic and anoxygenic chlorophototrophs with distinctive biomarker signatures populating the microbial mat. The transition of oxic to anoxic conditions is characterized by an accumulation of biomarkers indicative of anoxygenic phototrophy. It is also identified as a clear boundary for different species and ecotypes, which adjust their biomarker inventory, particularly the interplay of quinones and chloropigments, to prevailing conditions. Colocalization of the different biomarker groups led to the identification of characteristic IPL signatures and indicates that glycosidic diether glycerolipids are diagnostic for anoxygenic phototrophs in this mat system. The zoom-in into the upper green part further reveals how oxygenic and anoxygenic phototrophs share this microenvironment and informs on subtle, microscale adjustments in lipid composition of Synechococcus spp.
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Affiliation(s)
- Lars Wörmer
- MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Niroshan Gajendra
- MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Florence Schubotz
- MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany
| | - Emily D Matys
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Thomas W Evans
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kai-Uwe Hinrichs
- MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany
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11
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Hot in Cold: Microbial Life in the Hottest Springs in Permafrost. Microorganisms 2020; 8:microorganisms8091308. [PMID: 32867302 PMCID: PMC7565842 DOI: 10.3390/microorganisms8091308] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/22/2020] [Accepted: 08/25/2020] [Indexed: 12/26/2022] Open
Abstract
Chukotka is an arctic region located in the continuous permafrost zone, but thermal springs are abundant there. In this study, for the first time, the microbial communities of the Chukotka hot springs (CHS) biofilms and sediments with temperatures 54–94 °C were investigated and analyzed by NGS sequencing of 16S rRNA gene amplicons. In microbial mats (54–75 °C), phototrophic bacteria of genus Chloroflexus dominated (up to 89% of all prokaryotes), while Aquificae were the most numerous at higher temperatures in Fe-rich sediments and filamentous “streamers” (up to 92%). The electron donors typical for Aquificae, such as H2S and H2, are absent or present only in trace amounts, and the prevalence of Aquificae might be connected with their ability to oxidize the ferrous iron present in CHS sediments. Armatimonadetes, Proteobacteria, Deinococcus-Thermus, Dictyoglomi, and Thermotogae, as well as uncultured bacteria (candidate divisions Oct-Spa1-106, GAL15, and OPB56), were numerous, and Cyanobacteria were present in low numbers. Archaea (less than 8% of the total community of each tested spring) belonged to Bathyarchaeota, Aigarchaeota, and Thaumarchaeota. The geographical location and the predominantly autotrophic microbial community, built on mechanisms other than the sulfur cycle-based ones, make CHS a special and unique terrestrial geothermal ecosystem.
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12
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Boyer GM, Schubotz F, Summons RE, Woods J, Shock EL. Carbon Oxidation State in Microbial Polar Lipids Suggests Adaptation to Hot Spring Temperature and Redox Gradients. Front Microbiol 2020; 11:229. [PMID: 32153529 PMCID: PMC7044123 DOI: 10.3389/fmicb.2020.00229] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 01/31/2020] [Indexed: 12/18/2022] Open
Abstract
The influence of oxidation-reduction (redox) potential on the expression of biomolecules is a topic of ongoing exploration in geobiology. In this study, we investigate the novel possibility that structures and compositions of lipids produced by microbial communities are sensitive to environmental redox conditions. We extracted lipids from microbial biomass collected along the thermal and redox gradients of four alkaline hot springs in Yellowstone National Park (YNP) and investigated patterns in the average oxidation state of carbon (ZC), a metric calculated from the chemical formulae of lipid structures. Carbon in intact polar lipids (IPLs) and their alkyl chains becomes more oxidized (higher ZC) with increasing distance from each of the four hot spring sources. This coincides with decreased water temperature and increased concentrations of oxidized inorganic solutes, such as dissolved oxygen, sulfate, and nitrate. Carbon in IPLs is most reduced (lowest ZC) in the hot, reduced conditions upstream, with abundance-weighted ZC values between −1.68 and −1.56. These values increase gradually downstream to around −1.36 to −1.33 in microbial communities living between 29.0 and 38.1°C. This near-linear increase in ZC can be attributed to a shift from ether-linked to ester-linked alkyl chains, a decrease in average aliphatic carbons per chain (nC), an increase in average degree of unsaturation per chain (nUnsat), and increased cyclization in tetraether lipids. The ZC of lipid headgroups and backbones did not change significantly downstream. Expression of lipids with relatively reduced carbon under reduced conditions and oxidized lipids under oxidized conditions may indicate microbial adaptation across environmental gradients in temperature and electron donor/acceptor supply.
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Affiliation(s)
- Grayson M Boyer
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States
| | - Florence Schubotz
- MARUM and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Roger E Summons
- Department of Earth, Atmospheric and Planetary Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jade Woods
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Everett L Shock
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States.,School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
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13
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Colman DR, Lindsay MR, Amenabar MJ, Boyd ES. The Intersection of Geology, Geochemistry, and Microbiology in Continental Hydrothermal Systems. ASTROBIOLOGY 2019; 19:1505-1522. [PMID: 31592688 DOI: 10.1089/ast.2018.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Decompressional boiling of ascending hydrothermal waters and separation into a vapor (gas) and a liquid phase drive extensive variation in the geochemical composition of hot spring waters. Yet little is known of how the process of phase separation influences the distribution of microbial metabolisms in springs. Here, we determined the variation in protein coding genes in 51 metagenomes from chemosynthetic hot spring communities that span geochemical gradients in Yellowstone National Park. The 51 metagenomes could be divided into 5 distinct groups that correspond to low and high temperatures and acidic and circumneutral/alkaline springs. A fifth group primarily comprised metagenomes from springs with moderate acidity and that are influenced by elevated volcanic gas input. Protein homologs putatively involved in the oxidation of sulfur compounds, a process that leads to acidification of spring waters, in addition to those involved in the reduction of sulfur compounds were enriched in metagenomes from acidic springs sourced by vapor phase gases. Metagenomes from springs with evidence for elevated volcanic gas input were enriched in protein homologs putatively involved in oxidation of those gases, including hydrogen and methane. Finally, metagenomes from circumneutral/alkaline springs sourced by liquid phase waters were enriched in protein homologs putatively involved in heterotrophy and respiration of oxidized nitrogen compounds and oxygen. These results indicate that the geological process of phase separation shapes the ecology of thermophilic communities through its influence on the availability of nutrients in the form of gases, solutes, and minerals. Microbial acidification of hot spring waters further influences the kinetic and thermodynamic stabilities of nutrients and their bioavailability. These data therefore provide an important framework to understand how geological processes have shaped the evolutionary history of chemosynthetic thermophiles and how these organisms, in turn, have shaped their geochemical environments.
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Affiliation(s)
- Daniel R Colman
- Department of Microbiology & Immunology, Montana State University, Bozeman, Montana
| | - Melody R Lindsay
- Department of Microbiology & Immunology, Montana State University, Bozeman, Montana
| | | | - Eric S Boyd
- Department of Microbiology & Immunology, Montana State University, Bozeman, Montana
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14
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Thomas SC, Tamadonfar KO, Seymour CO, Lai D, Dodsworth JA, Murugapiran SK, Eloe-Fadrosh EA, Dijkstra P, Hedlund BP. Position-Specific Metabolic Probing and Metagenomics of Microbial Communities Reveal Conserved Central Carbon Metabolic Network Activities at High Temperatures. Front Microbiol 2019; 10:1427. [PMID: 31333598 PMCID: PMC6624737 DOI: 10.3389/fmicb.2019.01427] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 06/05/2019] [Indexed: 12/02/2022] Open
Abstract
Temperature is a primary driver of microbial community composition and taxonomic diversity; however, it is unclear to what extent temperature affects characteristics of central carbon metabolic pathways (CCMPs) at the community level. In this study, 16S rRNA gene amplicon and metagenome sequencing were combined with 13C-labeled metabolite probing of the CCMPs to assess community carbon metabolism along a temperature gradient (60–95°C) in Great Boiling Spring, NV. 16S rRNA gene amplicon diversity was inversely proportional to temperature, and Archaea were dominant at higher temperatures. KO richness and diversity were also inversely proportional to temperature, yet CCMP genes were similarly represented across the temperature gradient and many individual metagenome-assembled genomes had complete pathways. In contrast, genes encoding cellulosomes and many genes involved in plant matter degradation and photosynthesis were absent at higher temperatures. In situ13C-CO2 production from labeled isotopomer pairs of glucose, pyruvate, and acetate suggested lower relative oxidative pentose phosphate pathway activity and/or fermentation at 60°C, and a stable or decreased maintenance energy demand at higher temperatures. Catabolism of 13C-labeled citrate, succinate, L-alanine, L-serine, and L-cysteine was observed at 85°C, demonstrating broad heterotrophic activity and confirming functioning of the TCA cycle. Together, these results suggest that temperature-driven losses in biodiversity and gene content in geothermal systems may not alter CCMP function or maintenance energy demands at a community level.
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Affiliation(s)
- Scott C Thomas
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Kevin O Tamadonfar
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Cale O Seymour
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Dengxun Lai
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States
| | - Jeremy A Dodsworth
- Department of Biology, California State University, San Bernardino, CA, United States
| | | | - Emiley A Eloe-Fadrosh
- Department of Energy Joint Genome Institute, Joint Genome Institute, Walnut Creek, CA, United States
| | - Paul Dijkstra
- Department of Biological Sciences, Center of Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, United States
| | - Brian P Hedlund
- School of Life Sciences, University of Nevada, Las Vegas, NV, United States.,Nevada Institute of Personalized Medicine, University of Nevada, Las Vegas, NV, United States
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15
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Gomez-Saez GV, Pop Ristova P, Sievert SM, Elvert M, Hinrichs KU, Bühring SI. Relative Importance of Chemoautotrophy for Primary Production in a Light Exposed Marine Shallow Hydrothermal System. Front Microbiol 2017; 8:702. [PMID: 28484442 PMCID: PMC5399606 DOI: 10.3389/fmicb.2017.00702] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/05/2017] [Indexed: 01/09/2023] Open
Abstract
The unique geochemistry of marine shallow-water hydrothermal systems promotes the establishment of diverse microbial communities with a range of metabolic pathways. In contrast to deep-sea vents, shallow-water vents not only support chemosynthesis, but also phototrophic primary production due to the availability of light. However, comprehensive studies targeting the predominant biogeochemical processes are rare, and consequently a holistic understanding of the functioning of these ecosystems is currently lacking. To this end, we combined stable isotope probing of lipid biomarkers with an analysis of the bacterial communities to investigate if chemoautotrophy, in parallel to photoautotrophy, plays an important role in autotrophic carbon fixation and to identify the key players. The study was carried out at a marine shallow-water hydrothermal system located at 5 m water depth off Dominica Island (Lesser Antilles), characterized by up to 55°C warm hydrothermal fluids that contain high amounts of dissolved Fe2+. Analysis of the bacterial diversity revealed Anaerolineae of the Chloroflexi as the most abundant bacterial class. Furthermore, the presence of key players involved in iron cycling generally known from deep-sea hydrothermal vents (e.g., Zetaproteobacteria and Geothermobacter), supported the importance of iron-driven redox processes in this hydrothermal system. Uptake of 13C-bicarbonate into bacterial fatty acids under light and dark conditions revealed active photo- and chemoautotrophic communities, with chemoautotrophy accounting for up to 65% of the observed autotrophic carbon fixation. Relatively increased 13C-incorporation in the dark allowed the classification of aiC15:0, C15:0, and iC16:0 as potential lipid biomarkers for bacterial chemoautotrophy in this ecosystem. Highest total 13C-incorporation into fatty acids took place at the sediment surface, but chemosynthesis was found to be active down to 8 cm sediment depth. In conclusion, this study highlights the relative importance of chemoautotrophy compared to photoautotrophy in a shallow-water hydrothermal system, emphasizing chemosynthesis as a prominent process for biomass production in marine coastal environments influenced by hydrothermalism.
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Affiliation(s)
- Gonzalo V Gomez-Saez
- Hydrothermal Geomicrobiology Group, MARUM - Center for Marine Environmental Sciences, University of BremenBremen, Germany
| | - Petra Pop Ristova
- Hydrothermal Geomicrobiology Group, MARUM - Center for Marine Environmental Sciences, University of BremenBremen, Germany
| | - Stefan M Sievert
- Biology Department, Woods Hole Oceanographic Institution, Woods HoleMA, USA
| | - Marcus Elvert
- Organic Geochemistry Group, MARUM - Center for Marine Environmental Sciences and Department of Geosciences, University of BremenBremen, Germany
| | - Kai-Uwe Hinrichs
- Organic Geochemistry Group, MARUM - Center for Marine Environmental Sciences and Department of Geosciences, University of BremenBremen, Germany
| | - Solveig I Bühring
- Hydrothermal Geomicrobiology Group, MARUM - Center for Marine Environmental Sciences, University of BremenBremen, Germany
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16
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Colman DR, Feyhl-Buska J, Robinson KJ, Fecteau KM, Xu H, Shock EL, Boyd ES. Ecological differentiation in planktonic and sediment-associated chemotrophic microbial populations in Yellowstone hot springs. FEMS Microbiol Ecol 2016; 92:fiw137. [PMID: 27306555 DOI: 10.1093/femsec/fiw137] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2016] [Indexed: 01/29/2023] Open
Abstract
Chemosynthetic sediment and planktonic community composition and sizes, aqueous geochemistry and sediment mineralogy were determined in 15 non-photosynthetic hot springs in Yellowstone National Park (YNP). These data were used to evaluate the hypothesis that differences in the availability of dissolved or mineral substrates in the bulk fluids or sediments within springs coincides with ecologically differentiated microbial communities and their populations. Planktonic and sediment-associated communities exhibited differing ecological characteristics including community sizes, evenness and richness. pH and temperature influenced microbial community composition among springs, but within-spring partitioning of taxa into sediment or planktonic communities was widespread, statistically supported (P < 0.05) and could be best explained by the inferred metabolic strategies of the partitioned taxa. Microaerophilic genera of the Aquificales predominated in many of the planktonic communities. In contrast, taxa capable of mineral-based metabolism such as S(o) oxidation/reduction or Fe-oxide reduction predominated in sediment communities. These results indicate that ecological differentiation within thermal spring habitats is common across a range of spring geochemistry and is influenced by the availability of dissolved nutrients and minerals that can be used in metabolism.
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Affiliation(s)
- Daniel R Colman
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Jayme Feyhl-Buska
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Kirtland J Robinson
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | | | - Huifang Xu
- Department of Geosciences, University of Wisconsin, Madison, WI 53706, USA NASA Astrobiology Institute, Mountain View, CA 94035, USA School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Everett L Shock
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA NASA Astrobiology Institute, Mountain View, CA 94035, USA School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA NASA Astrobiology Institute, Mountain View, CA 94035, USA School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
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17
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Fortney NW, He S, Converse BJ, Beard BL, Johnson CM, Boyd ES, Roden EE. Microbial Fe(III) oxide reduction potential in Chocolate Pots hot spring, Yellowstone National Park. GEOBIOLOGY 2016; 14:255-275. [PMID: 26750514 DOI: 10.1111/gbi.12173] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 11/10/2015] [Indexed: 06/05/2023]
Abstract
Chocolate Pots hot springs (CP) is a unique, circumneutral pH, iron-rich, geothermal feature in Yellowstone National Park. Prior research at CP has focused on photosynthetically driven Fe(II) oxidation as a model for mineralization of microbial mats and deposition of Archean banded iron formations. However, geochemical and stable Fe isotopic data have suggested that dissimilatory microbial iron reduction (DIR) may be active within CP deposits. In this study, the potential for microbial reduction of native CP Fe(III) oxides was investigated, using a combination of cultivation dependent and independent approaches, to assess the potential involvement of DIR in Fe redox cycling and associated stable Fe isotope fractionation in the CP hot springs. Endogenous microbial communities were able to reduce native CP Fe(III) oxides, as documented by most probable number enumerations and enrichment culture studies. Enrichment cultures demonstrated sustained DIR driven by oxidation of acetate, lactate, and H2 . Inhibitor studies and molecular analyses indicate that sulfate reduction did not contribute to observed rates of DIR in the enrichment cultures through abiotic reaction pathways. Enrichment cultures produced isotopically light Fe(II) during DIR relative to the bulk solid-phase Fe(III) oxides. Pyrosequencing of 16S rRNA genes from enrichment cultures showed dominant sequences closely affiliated with Geobacter metallireducens, a mesophilic Fe(III) oxide reducer. Shotgun metagenomic analysis of enrichment cultures confirmed the presence of a dominant G. metallireducens-like population and other less dominant populations from the phylum Ignavibacteriae, which appear to be capable of DIR. Gene (protein) searches revealed the presence of heat-shock proteins that may be involved in increased thermotolerance in the organisms present in the enrichments as well as porin-cytochrome complexes previously shown to be involved in extracellular electron transport. This analysis offers the first detailed insight into how DIR may impact the Fe geochemistry and isotope composition of a Fe-rich, circumneutral pH geothermal environment.
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Affiliation(s)
- N W Fortney
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - S He
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - B J Converse
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - B L Beard
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - C M Johnson
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - E S Boyd
- Department of Microbiology and Immunology, NASA Astrobiology Institute, Montana State University, Bozeman, MT, USA
| | - E E Roden
- Department of Geoscience, NASA Astrobiology Institute, University of Wisconsin-Madison, Madison, WI, USA
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18
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Charles CJ, Rout SP, Garratt EJ, Patel K, Laws AP, Humphreys PN. The enrichment of an alkaliphilic biofilm consortia capable of the anaerobic degradation of isosaccharinic acid from cellulosic materials incubated within an anthropogenic, hyperalkaline environment. FEMS Microbiol Ecol 2015. [PMID: 26195600 PMCID: PMC4629871 DOI: 10.1093/femsec/fiv085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Anthropogenic hyperalkaline sites provide an environment that is analogous to proposed cementitious geological disposal facilities (GDF) for radioactive waste. Under anoxic, alkaline conditions cellulosic wastes will hydrolyze to a range of cellulose degradation products (CDP) dominated by isosaccharinic acids (ISA). In order to investigate the potential for microbial activity in a cementitious GDF, cellulose samples were incubated in the alkaline (∼pH 12), anaerobic zone of a lime kiln waste site. Following retrieval, these samples had undergone partial alkaline hydrolysis and were colonized by a Clostridia-dominated biofilm community, where hydrogenotrophic, alkaliphilic methanogens were also present. When these samples were used to establish an alkaline CDP fed microcosm, the community shifted away from Clostridia, methanogens became undetectable and a flocculate community dominated by Alishewanella sp. established. These flocs were composed of bacteria embedded in polysaccharides and proteins stabilized by extracellular DNA. This community was able to degrade all forms of ISA with >60% of the carbon flow being channelled into extracellular polymeric substance (EPS) production. This study demonstrated that alkaliphilic microbial communities can degrade the CDP associated with some radioactive waste disposal concepts at pH 11. These communities divert significant amounts of degradable carbon to EPS formation, suggesting that EPS has a central role in the protection of these communities from hyperalkaline conditions.
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Affiliation(s)
- C J Charles
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - S P Rout
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - E J Garratt
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - K Patel
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - A P Laws
- Department of Chemical Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - P N Humphreys
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
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19
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Carbon source preference in chemosynthetic hot spring communities. Appl Environ Microbiol 2015; 81:3834-47. [PMID: 25819970 DOI: 10.1128/aem.00511-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/23/2015] [Indexed: 11/20/2022] Open
Abstract
Rates of dissolved inorganic carbon (DIC), formate, and acetate mineralization and/or assimilation were determined in 13 high-temperature (>73 °C) hot springs in Yellowstone National Park (YNP), Wyoming, in order to evaluate the relative importance of these substrates in supporting microbial metabolism. While 9 of the hot spring communities exhibited rates of DIC assimilation that were greater than those of formate and acetate assimilation, 2 exhibited rates of formate and/or acetate assimilation that exceeded those of DIC assimilation. Overall rates of DIC, formate, and acetate mineralization and assimilation were positively correlated with spring pH but showed little correlation with temperature. Communities sampled from hot springs with similar geochemistries generally exhibited similar rates of substrate transformation, as well as similar community compositions, as revealed by 16S rRNA gene-tagged sequencing. Amendment of microcosms with small (micromolar) amounts of formate suppressed DIC assimilation in short-term (<45-min) incubations, despite the presence of native DIC concentrations that exceeded those of added formate by 2 to 3 orders of magnitude. The concentration of added formate required to suppress DIC assimilation was similar to the affinity constant (K(m)) for formate transformation, as determined by community kinetic assays. These results suggest that dominant chemoautotrophs in high-temperature communities are facultatively autotrophic or mixotrophic, are adapted to fluctuating nutrient availabilities, and are capable of taking advantage of energy-rich organic substrates when they become available.
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20
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Wörmer L, Lipp JS, Hinrichs KU. Comprehensive Analysis of Microbial Lipids in Environmental Samples Through HPLC-MS Protocols. SPRINGER PROTOCOLS HANDBOOKS 2015. [DOI: 10.1007/8623_2015_183] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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