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Verrone V, Gupta A, Laloo AE, Dubey RK, Hamid NAA, Swarup S. Organic matter stability and lability in terrestrial and aquatic ecosystems: A chemical and microbial perspective. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167757. [PMID: 37852479 DOI: 10.1016/j.scitotenv.2023.167757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/20/2023]
Abstract
Terrestrial and aquatic ecosystems have specific carbon fingerprints and sequestration potential, due to the intrinsic properties of the organic matter (OM), mineral content, environmental conditions, and microbial community composition and functions. A small variation in the OM pool can imbalance the carbon dynamics that ultimately affect the climate and functionality of each ecosystem, at regional and global scales. Here, we review the factors that continuously contribute to carbon stability and lability, with particular attention to the OM formation and nature, as well as the microbial activities that drive OM aggregation, degradation and eventually greenhouse gas emissions. We identified that in both aquatic and terrestrial ecosystems, microbial attributes (i.e., carbon metabolism, carbon use efficiency, necromass, enzymatic activities) play a pivotal role in transforming the carbon stock and yet they are far from being completely characterised and not often included in carbon estimations. Therefore, future research must focus on the integration of microbial components into carbon mapping and models, as well as on translating molecular-scaled studies into practical approaches. These strategies will improve carbon management and restoration across ecosystems and contribute to overcome current climate challenges.
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Affiliation(s)
- Valeria Verrone
- National University of Singapore Environmental Research Institute, National University of Singapore,117411, Singapore
| | - Abhishek Gupta
- Singapore Centre of Environmental Engineering and Life Sciences, National University of Singapore, Singapore.
| | - Andrew Elohim Laloo
- National University of Singapore Environmental Research Institute, National University of Singapore,117411, Singapore; Singapore Centre of Environmental Engineering and Life Sciences, National University of Singapore, Singapore
| | - Rama Kant Dubey
- National University of Singapore Environmental Research Institute, National University of Singapore,117411, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore; Department of Biotechnology, GLA University, Mathura, Uttar Pradesh 281406, India
| | - Nur Ashikin Abdul Hamid
- National University of Singapore Environmental Research Institute, National University of Singapore,117411, Singapore
| | - Sanjay Swarup
- National University of Singapore Environmental Research Institute, National University of Singapore,117411, Singapore; Singapore Centre of Environmental Engineering and Life Sciences, National University of Singapore, Singapore; Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore
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Sajjad W, Ali B, Niu H, Ilahi N, Rafiq M, Bahadur A, Banerjee A, Kang S. High prevalence of antibiotic-resistant and metal-tolerant cultivable bacteria in remote glacier environment. ENVIRONMENTAL RESEARCH 2023; 239:117444. [PMID: 37858689 DOI: 10.1016/j.envres.2023.117444] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/04/2023] [Accepted: 10/17/2023] [Indexed: 10/21/2023]
Abstract
Studies of antibiotic-resistant bacteria (ARB) have mainly originated from anthropic-influenced environments, with limited information from pristine environments. Remote cold environments are major reservoirs of ARB and have been determined in polar regions; however, their abundance in non-polar cold habitats is underexplored. This study evaluated antibiotics and metals resistance profiles, prevalence of antibiotic resistance genes (ARGs) and metals tolerance genes (MTGs) in 38 ARB isolated from the glacier debris and meltwater from Baishui Glacier No 1, China. Molecular identification displayed Proteobacteria (39.3%) predominant in debris, while meltwater was dominated by Actinobacteria (30%) and Proteobacteria (30%). Bacterial isolates exhibited multiple antibiotic resistance index values > 0.2. Gram-negative bacteria displayed higher resistance to antibiotics and metals than Gram-positive. PCR amplification exhibited distinct ARGs in bacteria dominated by β-lactam genes blaCTX-M (21.1-71.1%), blaACC (21.1-60.5%), tetracycline-resistant gene tetA (21.1-60.5%), and sulfonamide-resistant gene sulI (18.4-52.6%). Moreover, different MTGs were reported in bacterial isolates, including mercury-resistant merA (21.1-63.2%), copper-resistant copB (18.4-57.9%), chromium-resistant chrA (15.8-44.7%) and arsenic-resistant arsB (10.5-44.7%). This highlights the co-selection and co-occurrence of MTGs and ARGs in remote glacier environments. Different bacteria shared same ARGs, signifying horizontal gene transfer between species. Strong positive correlation among ARGs and MTGs was reported. Metals tolerance range exhibited that Gram-negative and Gram-positive bacteria clustered distinctly. Gram-negative bacteria were significantly tolerant to metals. Amino acid sequences of blaACC,blaCTX-M,blaSHV,blaampC,qnrA, sulI, tetA and blaTEM revealed variations. This study presents promising ARB, harboring ARGs with variations in amino acid sequences, highlighting the need to assess the transcriptome study of glacier bacteria conferring ARGs and MTGs.
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Affiliation(s)
- Wasim Sajjad
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Barkat Ali
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Hewen Niu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China; National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Nikhat Ilahi
- State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems, College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Muhammad Rafiq
- Department of Microbiology, Faculty of Life Sciences and Informatics, Engineering and Management Sciences, Balochistan University of Information Technology, Quetta, Pakistan
| | - Ali Bahadur
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Abhishek Banerjee
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
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Giovannelli D, Barry PH, de Moor JM, Jessen GL, Schrenk MO, Lloyd KG. Sampling across large-scale geological gradients to study geosphere–biosphere interactions. Front Microbiol 2022; 13:998133. [PMID: 36386678 PMCID: PMC9659755 DOI: 10.3389/fmicb.2022.998133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/05/2022] [Indexed: 12/02/2022] Open
Abstract
Despite being one of the largest microbial ecosystems on Earth, many basic open questions remain about how life exists and thrives in the deep subsurface biosphere. Much of this ambiguity is due to the fact that it is exceedingly difficult and often prohibitively expensive to directly sample the deep subsurface, requiring elaborate drilling programs or access to deep mines. We propose a sampling approach which involves collection of a large suite of geological, geochemical, and biological data from numerous deeply-sourced seeps—including lower temperature sites—over large spatial scales. This enables research into interactions between the geosphere and the biosphere, expanding the classical local approach to regional or even planetary scales. Understanding the interplay between geology, geochemistry and biology on such scales is essential for building subsurface ecosystem models and extrapolating the ecological and biogeochemical roles of subsurface microbes beyond single site interpretations. This approach has been used successfully across the Central and South American Convergent Margins, and can be applied more broadly to other types of geological regions (i.e., rifting, intraplate volcanic, and hydrothermal settings). Working across geological spatial scales inherently encompasses broad temporal scales (e.g., millions of years of volatile cycling across a convergent margin), providing access to a framework for interpreting evolution and ecosystem functions through deep time and space. We propose that tectonic interactions are fundamental to maintaining planetary habitability through feedbacks that stabilize the ecosphere, and deep biosphere studies are fundamental to understanding geo-bio feedbacks on these processes on a global scale.
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Affiliation(s)
- Donato Giovannelli
- Department of Biology, University of Naples “Federico II”, Naples, Italy
- Institute of Marine Biological Resources and Biotechnologies, National Research Council, CNR-IRBIM, Ancona, Italy
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, United States
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, MA, United States
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
- *Correspondence: Donato Giovannelli,
| | - Peter H. Barry
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, MA, United States
| | - J. Maarten de Moor
- Observatorio Volcanológico y Sismológico de Costa Rica (OVSICORI), Universidad Nacional, Heredia, Costa Rica
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, United States
| | - Gerdhard L. Jessen
- Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile
- Center for Oceanographic Research COPAS COASTAL, Universidad de Concepción, Concepción, Chile
| | - Matthew O. Schrenk
- Department of Earth and Environmental Sciences, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States
| | - Karen G. Lloyd
- Microbiology Department, University of Tennessee, Knoxville, TN, United States
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Sahu RP, Kazy SK, Bose H, Mandal S, Dutta A, Saha A, Roy S, Dutta Gupta S, Mukherjee A, Sar P. Microbial diversity and function in crystalline basement beneath the Deccan Traps explored in a 3 km borehole at Koyna, western India. Environ Microbiol 2021; 24:2837-2853. [PMID: 34897962 DOI: 10.1111/1462-2920.15867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/29/2021] [Accepted: 12/05/2021] [Indexed: 12/20/2022]
Abstract
Deep terrestrial subsurface represents a huge repository of global prokaryotic biomass. Given its vastness and importance, microbial life within the deep subsurface continental crust remains under-represented in global studies. We characterize the microbial communities of deep, extreme and oligotrophic realm hosted by crystalline Archaean granitic rocks underneath the Deccan Traps, through sampling via 3000 m deep scientific borehole at Koyna, India through metagenomics, amplicon sequencing and cultivation-based analyses. Gene sequences 16S rRNA (7.37 × 106 ) show considerable bacterial diversity and the existence of a core microbiome (5724 operational taxonomic units conserved out of a total 118,064 OTUs) across the depths. Relative abundance of different taxa of core microbiome varies with depth in response to prevailing lithology and geochemistry. Co-occurrence network analysis and cultivation attempt to elucidate close interactions among autotrophic and organotrophic bacteria. Shotgun metagenomics reveals a major role of autotrophic carbon fixation via the Wood-Ljungdahl pathway and genes responsible for energy and carbon metabolism. Deeper analysis suggests the existence of an 'acetate switch', coordinating biosynthesis and cellular homeostasis. We conclude that the microbial life in the nutrient- and energy-limited deep granitic crust is constrained by the depth and managed by a few core members via a close interplay between autotrophy and organotrophy.
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Affiliation(s)
- Rajendra Prasad Sahu
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
| | - Sufia K Kazy
- Department of Biotechnology, National Institute of Technology Durgapur, Durgapur, WB, 713209, India
| | - Himadri Bose
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
| | - Sunanda Mandal
- Department of Biotechnology, National Institute of Technology Durgapur, Durgapur, WB, 713209, India
| | - Avishek Dutta
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
| | - Anumeha Saha
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
| | - Sukanta Roy
- Ministry of Earth Sciences, Borehole Geophysics Research Laboratory, Karad, MH, 415114, India
| | - Srimanti Dutta Gupta
- School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
| | - Abhijit Mukherjee
- School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India.,Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
| | - Pinaki Sar
- Environmental Microbiology and Genomics Laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, WB, 721302, India
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Exploration of deep terrestrial subsurface microbiome in Late Cretaceous Deccan traps and underlying Archean basement, India. Sci Rep 2018; 8:17459. [PMID: 30498254 PMCID: PMC6265293 DOI: 10.1038/s41598-018-35940-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 11/05/2018] [Indexed: 11/08/2022] Open
Abstract
Scientific deep drilling at Koyna, western India provides a unique opportunity to explore microbial life within deep biosphere hosted by ~65 Myr old Deccan basalt and Archaean granitic basement. Characteristic low organic carbon content, mafic/felsic nature but distinct trend in sulfate and nitrate concentrations demarcates the basaltic and granitic zones as distinct ecological habitats. Quantitative PCR indicates a depth independent distribution of microorganisms predominated by bacteria. Abundance of dsrB and mcrA genes are relatively higher (at least one order of magnitude) in basalt compared to granite. Bacterial communities are dominated by Alpha-, Beta-, Gammaproteobacteria, Actinobacteria and Firmicutes, whereas Euryarchaeota is the major archaeal group. Strong correlation among the abundance of autotrophic and heterotrophic taxa is noted. Bacteria known for nitrite, sulfur and hydrogen oxidation represent the autotrophs. Fermentative, nitrate/sulfate reducing and methane metabolising microorganisms represent the heterotrophs. Lack of shared operational taxonomic units and distinct clustering of major taxa indicate possible community isolation. Shotgun metagenomics corroborate that chemolithoautotrophic assimilation of carbon coupled with fermentation and anaerobic respiration drive this deep biosphere. This first report on the geomicrobiology of the subsurface of Deccan traps provides an unprecedented opportunity to understand microbial composition and function in the terrestrial, igneous rock-hosted, deep biosphere.
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Jones RM, Goordial JM, Orcutt BN. Low Energy Subsurface Environments as Extraterrestrial Analogs. Front Microbiol 2018; 9:1605. [PMID: 30072971 PMCID: PMC6058055 DOI: 10.3389/fmicb.2018.01605] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/27/2018] [Indexed: 11/13/2022] Open
Abstract
Earth's subsurface is often isolated from phototrophic energy sources and characterized by chemotrophic modes of life. These environments are often oligotrophic and limited in electron donors or electron acceptors, and include continental crust, subseafloor oceanic crust, and marine sediment as well as subglacial lakes and the subsurface of polar desert soils. These low energy subsurface environments are therefore uniquely positioned for examining minimum energetic requirements and adaptations for chemotrophic life. Current targets for astrobiology investigations of extant life are planetary bodies with largely inhospitable surfaces, such as Mars, Europa, and Enceladus. Subsurface environments on Earth thus serve as analogs to explore possibilities of subsurface life on extraterrestrial bodies. The purpose of this review is to provide an overview of subsurface environments as potential analogs, and the features of microbial communities existing in these low energy environments, with particular emphasis on how they inform the study of energetic limits required for life. The thermodynamic energetic calculations presented here suggest that free energy yields of reactions and energy density of some metabolic redox reactions on Mars, Europa, Enceladus, and Titan could be comparable to analog environments in Earth's low energy subsurface habitats.
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Affiliation(s)
| | | | - Beth N. Orcutt
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
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7
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Momper L, Kiel Reese B, Zinke L, Wanger G, Osburn MR, Moser D, Amend JP. Major phylum-level differences between porefluid and host rock bacterial communities in the terrestrial deep subsurface. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:501-511. [PMID: 28677247 DOI: 10.1111/1758-2229.12563] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 01/06/2017] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Earth's deep subsurface biosphere (DSB) is home to a vast number and wide variety of microorganisms. Although difficult to access and sample, deep subsurface environments have been probed through drilling programs, exploration of mines and sampling of deeply sourced vents and springs. In an effort to understand the ecology of deep terrestrial habitats, we examined bacterial diversity in the Sanford Underground Research Facility (SURF), the former Homestake gold mine, in South Dakota, USA. Whole genomic DNA was extracted from deeply circulating groundwater and corresponding host rock (at a depth of 1.45 km below ground surface). Pyrotag DNA sequencing of the 16S rRNA gene revealed diverse communities of putative chemolithoautotrophs, aerobic and anaerobic heterotrophs, numerous candidate phyla and unique rock-associated microbial assemblage. There was a clear and near-total separation of communities between SURF deeply circulating fracture fluids and SURF host-rocks. Sequencing data from SURF compared against five similarly sequenced terrestrial subsurface sites in Europe and North America revealed classes Clostridia and Betaproteobacteria were dominant in terrestrial fluids. This study presents a unique analysis showing differences in terrestrial subsurface microbial communities between fracture fluids and host rock through which those fluids permeate.
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Affiliation(s)
- Lily Momper
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, CA, USA
| | - Brandi Kiel Reese
- Department of Life Sciences, Texas A&M University, Corpus Christi, TX, USA
| | - Laura Zinke
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, CA, USA
| | - Greg Wanger
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA
| | - Magdalena R Osburn
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA
| | - Duane Moser
- Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas, NV, USA
| | - Jan P Amend
- Department of Biological Sciences, Marine Environmental Biology Section, University of Southern California, Los Angeles, CA, USA
- Department of Earth Sciences, University of Southern California, Los Angeles, CA, USA
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Rafiq M, Hayat M, Anesio AM, Jamil SUU, Hassan N, Shah AA, Hasan F. Recovery of metallo-tolerant and antibiotic resistant psychrophilic bacteria from Siachen glacier, Pakistan. PLoS One 2017; 12:e0178180. [PMID: 28746396 PMCID: PMC5528264 DOI: 10.1371/journal.pone.0178180] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 05/09/2017] [Indexed: 11/18/2022] Open
Abstract
Cultureable bacterial diversity of previously unexplored Siachen glacier, Pakistan, was studied. Out of 50 isolates 33 (66%) were Gram negative and 17 (34%) Gram positive. About half of the isolates were pigment producers and were able to grow at 4-37°C. 16S rRNA gene sequences revealed Gram negative bacteria dominated by Proteobacteria (especially γ-proteobacteria and β-proteobacteria) and Flavobacteria. The genus Pseudomonas (51.51%, 17) was dominant among γ- proteobacteria. β-proteobacteria constituted 4 (12.12%) Alcaligenes and 4 (12.12%) Janthinobacterium strains. Among Gram positive bacteria, phylum Actinobacteria, Rhodococcus (23.52%, 4) and Arthrobacter (23.52%, 4) were the dominating genra. Other bacteria belonged to Phylum Firmicutes with representative genus Carnobacterium (11.76%, 2) and 4 isolates represented 4 genera Bacillus, Lysinibacillus, Staphylococcus and Planomicrobium. Most of the Gram negative bacteria were moderate halophiles, while most of the Gram positives were extreme halophiles and were able to grow up to 6.12 M of NaCl. More than 2/3 of the isolates showed antimicrobial activity against multidrug resistant S. aureus, E. coli, Klebsiella pneumonia, Enterococcus faecium, Candida albicans, Aspergillus flavus and Aspergillus fumigatus and ATCC strains. Gram positive bacteria (94.11%) were more resistant to heavy metals as compared to Gram negative (78.79%) and showed maximum tolerance against iron and least tolerance against mercury.
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Affiliation(s)
- Muhammad Rafiq
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
- Department of Microbiology, Abdul Wali Khan University, Mardan, Pakistan
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Muhammad Hayat
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Alexandre M. Anesio
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Syed Umair Ullah Jamil
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
- Department of Earth and Environmental Sciences, Bahria University, Islamabad, Pakistan
| | - Noor Hassan
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Aamer Ali Shah
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Fariha Hasan
- Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan
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9
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Hays LE, Graham HV, Des Marais DJ, Hausrath EM, Horgan B, McCollom TM, Parenteau MN, Potter-McIntyre SL, Williams AJ, Lynch KL. Biosignature Preservation and Detection in Mars Analog Environments. ASTROBIOLOGY 2017; 17:363-400. [PMID: 28177270 PMCID: PMC5478115 DOI: 10.1089/ast.2016.1627] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
This review of material relevant to the Conference on Biosignature Preservation and Detection in Mars Analog Environments summarizes the meeting materials and discussions and is further expanded upon by detailed references to the published literature. From this diverse source material, there is a detailed discussion on the habitability and biosignature preservation potential of five primary analog environments: hydrothermal spring systems, subaqueous environments, subaerial environments, subsurface environments, and iron-rich systems. Within the context of exploring past habitable environments on Mars, challenges common to all of these key environments are laid out, followed by a focused discussion for each environment regarding challenges to orbital and ground-based observations and sample selection. This leads into a short section on how these challenges could influence our strategies and priorities for the astrobiological exploration of Mars. Finally, a listing of urgent needs and future research highlights key elements such as development of instrumentation as well as continued exploration into how Mars may have evolved differently from Earth and what that might mean for biosignature preservation and detection. Key Words: Biosignature preservation-Biosignature detection-Mars analog environments-Conference report-Astrobiological exploration. Astrobiology 17, 363-400.
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Affiliation(s)
- Lindsay E. Hays
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California
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Rempfert KR, Miller HM, Bompard N, Nothaft D, Matter JM, Kelemen P, Fierer N, Templeton AS. Geological and Geochemical Controls on Subsurface Microbial Life in the Samail Ophiolite, Oman. Front Microbiol 2017; 8:56. [PMID: 28223966 PMCID: PMC5293757 DOI: 10.3389/fmicb.2017.00056] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/09/2017] [Indexed: 02/06/2023] Open
Abstract
Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman. The geochemical compositions of subsurface fluids in the ophiolite are highly variable, reflecting differences in host rock composition and the extent of fluid-rock interaction. Principal component analysis of fluid geochemistry and geologic context indicate the presence of at least four fluid types in the Samail Ophiolite (“gabbro,” “alkaline peridotite,” “hyperalkaline peridotite,” and “gabbro/peridotite contact”) that vary strongly in pH and the concentrations of H2, CH4, Ca2+, Mg2+, NO3-, SO42-, trace metals, and DIC. Geochemistry of fluids is strongly correlated with microbial community composition; similar microbial assemblages group according to fluid type. Hyperalkaline fluids exhibit low diversity and are dominated by taxa related to the Deinococcus-Thermus genus Meiothermus, candidate phyla OP1, and the family Thermodesulfovibrionaceae. Gabbro- and alkaline peridotite- aquifers harbor more diverse communities and contain abundant microbial taxa affiliated with Nitrospira, Nitrosospharaceae, OP3, Parvarcheota, and OP1 order Acetothermales. Wells that sit at the contact between gabbro and peridotite host microbial communities distinct from all other fluid types, with an enrichment in betaproteobacterial taxa. Together the taxonomic information and geochemical data suggest that several metabolisms may be operative in subsurface fluids, including methanogenesis, acetogenesis, and fermentation, as well as the oxidation of methane, hydrogen and small molecular weight organic acids utilizing nitrate and sulfate as electron acceptors. Dynamic nitrogen cycling may be especially prevalent in gabbro and alkaline peridotite fluids. These data suggest water-rock reaction, as controlled by lithology and hydrogeology, constrains the distribution of life in terrestrial ophiolites.
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Affiliation(s)
- Kaitlin R Rempfert
- Department of Geological Sciences, University of Colorado Boulder, CO, USA
| | - Hannah M Miller
- Department of Geological Sciences, University of Colorado Boulder, CO, USA
| | - Nicolas Bompard
- National Oceanography Centre, University of Southampton Southampton, UK
| | - Daniel Nothaft
- Department of Geological Sciences, University of Colorado Boulder, CO, USA
| | - Juerg M Matter
- National Oceanography Centre, University of Southampton Southampton, UK
| | - Peter Kelemen
- Lamont-Doherty Earth Observatory, Columbia University Palisades, NY, USA
| | - Noah Fierer
- Cooperate Institute for Research in Environmental Sciences, University of ColoradoBoulder, CO, USA; Department of Ecology and Evolutionary Biology, University of ColoradoBoulder, CO, USA
| | - Alexis S Templeton
- Department of Geological Sciences, University of Colorado Boulder, CO, USA
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11
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Jangir Y, French S, Momper LM, Moser DP, Amend JP, El-Naggar MY. Isolation and Characterization of Electrochemically Active Subsurface Delftia and Azonexus Species. Front Microbiol 2016; 7:756. [PMID: 27242768 PMCID: PMC4876122 DOI: 10.3389/fmicb.2016.00756] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 05/05/2016] [Indexed: 11/29/2022] Open
Abstract
Continental subsurface environments can present significant energetic challenges to the resident microorganisms. While these environments are geologically diverse, potentially allowing energy harvesting by microorganisms that catalyze redox reactions, many of the abundant electron donors and acceptors are insoluble and therefore not directly bioavailable. Extracellular electron transfer (EET) is a metabolic strategy that microorganisms can deploy to meet the challenges of interacting with redox-active surfaces. Though mechanistically characterized in a few metal-reducing bacteria, the role, extent, and diversity of EET in subsurface ecosystems remains unclear. Since this process can be mimicked on electrode surfaces, it opens the door to electrochemical techniques to enrich for and quantify the activities of environmental microorganisms in situ. Here, we report the electrochemical enrichment of microorganisms from a deep fractured-rock aquifer in Death Valley, CA, USA. In experiments performed in mesocosms containing a synthetic medium based on aquifer chemistry, four working electrodes (WEs) were poised at different redox potentials (272, 373, 472, 572 mV vs. SHE) to serve as electron acceptors, resulting in anodic currents coupled to the oxidation of acetate during enrichment. The anodes were dominated by Betaproteobacteria from the families Comamonadaceae and Rhodocyclaceae. A representative of each dominant family was subsequently isolated from electrode-associated biomass. The EET abilities of the isolated Delftia strain (designated WE1-13) and Azonexus strain (designated WE2-4) were confirmed in electrochemical reactors using WEs poised at 522 mV vs. SHE. The rise in anodic current upon inoculation was correlated with a modest increase in total protein content. Both genera have been previously observed in mixed communities of microbial fuel cell enrichments, but this is the first direct measurement of their electrochemical activity. While alternate metabolisms (e.g., nitrate reduction) by these organisms were previously known, our observations suggest that additional ‘hidden’ interactions with external electron acceptors are also possible. Electrochemical approaches are well positioned to dissect such extracellular interactions that may be prevalent in the subsurface.
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Affiliation(s)
- Yamini Jangir
- Department of Physics and Astronomy, University of Southern California, Los Angeles CA, USA
| | - Sarah French
- Department of Physics and Astronomy, University of Southern California, Los Angeles CA, USA
| | - Lily M Momper
- Department of Biological Sciences, University of Southern California, Los Angeles CA, USA
| | - Duane P Moser
- Division of Earth and Ecosystem Sciences, Desert Research Institute, Las Vegas NV, USA
| | - Jan P Amend
- Department of Biological Sciences, University of Southern California, Los AngelesCA, USA; Department of Earth Sciences, University of Southern California, Los AngelesCA, USA
| | - Mohamed Y El-Naggar
- Department of Physics and Astronomy, University of Southern California, Los AngelesCA, USA; Department of Biological Sciences, University of Southern California, Los AngelesCA, USA; Department of Chemistry, University of Southern California, Los AngelesCA, USA
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