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Turrini P, Chebbi A, Riggio FP, Visca P. The geomicrobiology of limestone, sulfuric acid speleogenetic, and volcanic caves: basic concepts and future perspectives. Front Microbiol 2024; 15:1370520. [PMID: 38572233 PMCID: PMC10987966 DOI: 10.3389/fmicb.2024.1370520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/07/2024] [Indexed: 04/05/2024] Open
Abstract
Caves are ubiquitous subterranean voids, accounting for a still largely unexplored surface of the Earth underground. Due to the absence of sunlight and physical segregation, caves are naturally colonized by microorganisms that have developed distinctive capabilities to thrive under extreme conditions of darkness and oligotrophy. Here, the microbiomes colonizing three frequently studied cave types, i.e., limestone, sulfuric acid speleogenetic (SAS), and lava tubes among volcanic caves, have comparatively been reviewed. Geological configurations, nutrient availability, and energy flows in caves are key ecological drivers shaping cave microbiomes through photic, twilight, transient, and deep cave zones. Chemoheterotrophic microbial communities, whose sustenance depends on nutrients supplied from outside, are prevalent in limestone and volcanic caves, while elevated inorganic chemical energy is available in SAS caves, enabling primary production through chemolithoautotrophy. The 16S rRNA-based metataxonomic profiles of cave microbiomes were retrieved from previous studies employing the Illumina platform for sequencing the prokaryotic V3-V4 hypervariable region to compare the microbial community structures from different cave systems and environmental samples. Limestone caves and lava tubes are colonized by largely overlapping bacterial phyla, with the prevalence of Pseudomonadota and Actinomycetota, whereas the co-dominance of Pseudomonadota and Campylobacterota members characterizes SAS caves. Most of the metataxonomic profiling data have so far been collected from the twilight and transient zones, while deep cave zones remain elusive, deserving further exploration. Integrative approaches for future geomicrobiology studies are suggested to gain comprehensive insights into the different cave types and zones. This review also poses novel research questions for unveiling the metabolic and genomic capabilities of cave microorganisms, paving the way for their potential biotechnological applications.
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Affiliation(s)
- Paolo Turrini
- Department of Science, Roma Tre University, Rome, Italy
| | - Alif Chebbi
- Department of Science, Roma Tre University, Rome, Italy
| | | | - Paolo Visca
- Department of Science, Roma Tre University, Rome, Italy
- National Biodiversity Future Center, Palermo, Italy
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Gogoleva N, Chervyatsova O, Balkin A, Kuzmina L, Shagimardanova E, Kiseleva D, Gogolev Y. Microbial tapestry of the Shulgan-Tash cave (Southern Ural, Russia): influences of environmental factors on the taxonomic composition of the cave biofilms. ENVIRONMENTAL MICROBIOME 2023; 18:82. [PMID: 37990336 PMCID: PMC10662634 DOI: 10.1186/s40793-023-00538-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/09/2023] [Indexed: 11/23/2023]
Abstract
BACKGROUND Cave biotopes are characterized by stable low temperatures, high humidity, and scarcity of organic substrates. Despite the harsh oligotrophic conditions, they are often inhabited by rich microbial communities. Abundant fouling with a wide range of morphology and coloration of colonies covers the walls of the Shulgan-Tash cave in the Southern Urals. This cave is also famous for the unique Paleolithic painting discovered in the middle of the last century. We aimed to investigate the diversity, distribution, and potential impact of these biofilms on the cave's Paleolithic paintings, while exploring how environmental factors influence the microbial communities within the cave. RESULTS The cave's biofilm morphotypes were categorized into three types based on the ultrastructural similarities. Molecular taxonomic analysis identified two main clusters of microbial communities, with Actinobacteria dominating in most of them and a unique "CaveCurd" community with Gammaproteobacteria prevalent in the deepest cave sections. The species composition of these biofilms reflects changes in environmental conditions, such as substrate composition, temperature, humidity, ventilation, and CO2 content. Additionally, it was observed that cave biofilms contribute to biocorrosion on cave wall surfaces. CONCLUSIONS The Shulgan-Tash cave presents an intriguing example of a stable extreme ecosystem with diverse microbiota. However, the intense dissolution and deposition of carbonates caused by Actinobacteria pose a potential threat to the preservation of the cave's ancient rock paintings.
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Affiliation(s)
- Natalia Gogoleva
- Research Department for Limnology, Mondsee, Universität Innsbruck, Mondsee, 5310, Austria.
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420111, Russia.
| | | | - Alexander Balkin
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420111, Russia
- Institute for Cellular and Intracellular Symbiosis, Ural Branch of the Russian Academy of Sciences, Orenburg, 460000, Russia
| | - Lyudmila Kuzmina
- Ufa Institute of Biology, Ufa Federal Research Center, Russian Academy of Sciences, Ufa, 450054, Russia
| | - Elena Shagimardanova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420111, Russia
- Loginov Moscow Clinical Scientific Center, Moscow, 111123, Russia
| | - Daria Kiseleva
- Institute of Geology and Geochemistry, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, 620016, Russia
- Institute of Fundamental Education, Ural Federal University named after the first President of Russia B.N. Yeltsin, Ekaterinburg, 620002, Russia
| | - Yuri Gogolev
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420111, Russia
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Kazan, 420111, Russia
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3
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Cheng X, Wang H, Zeng Z, Li L, Zhao R, Bodelier PLE, Wang Y, Liu X, Su C, Liu S. Niche differentiation of atmospheric methane-oxidizing bacteria and their community assembly in subsurface karst caves. ENVIRONMENTAL MICROBIOLOGY REPORTS 2022; 14:886-896. [PMID: 35925016 DOI: 10.1111/1758-2229.13112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/05/2022] [Accepted: 07/17/2022] [Indexed: 06/17/2023]
Abstract
Karst caves are recently proposed as atmospheric methane sinks in terrestrial ecosystems. Despite of the detection of atmospheric methane-oxidizing bacteria (atmMOB) in caves, we still know little about their ecology and potential ability of methane oxidation in this ecosystem. To understand atmMOB ecology and their potential in methane consumption, we collected weathered rocks and sediments from three different caves in southwestern China. We determined the potential methane oxidization rates in the range of 1.25 ± 0.08 to 1.87 ± 0.41 ng CH4 g-1 DW h-1 , which are comparable to those reported in forest and grassland soils. Results showed that alkaline oligotrophic caves harbour high numbers of atmMOB, particularly upland soil cluster (USC), which significantly correlated with temperature, CH4 and CO2 concentrations. The absolute abundance of USCγ was higher than that of USCα. USCγ-OPS (open patch soil) and USCγ-SS (subsurface soil) dominated in most samples, whereas USCα-BFS (boreal forest soil) only predominated in the sediments near cave entrances, indicating niche differentiation of atmMOB in caves. Overwhelming dominance of homogenous selection in community assembly resulted in convergence of atmMOB communities. Collectively, our results demonstrated the niche differentiation of USC in subsurface alkaline caves and their non-negligible methane-oxidizing potential, providing brand-new knowledge about atmMOB ecology in subsurface biosphere.
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Affiliation(s)
- Xiaoyu Cheng
- State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Wuhan, P. R. China
- School of Environmental Studies, China University of Geosciences, Wuhan, P. R. China
| | - Hongmei Wang
- State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Wuhan, P. R. China
- School of Environmental Studies, China University of Geosciences, Wuhan, P. R. China
| | - Zhilin Zeng
- State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Wuhan, P. R. China
- School of Environmental Studies, China University of Geosciences, Wuhan, P. R. China
| | - Lu Li
- State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Wuhan, P. R. China
- School of Environmental Studies, China University of Geosciences, Wuhan, P. R. China
| | - Rui Zhao
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Paul L E Bodelier
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Yiheng Wang
- State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Wuhan, P. R. China
- School of Environmental Studies, China University of Geosciences, Wuhan, P. R. China
| | - Xiaoyan Liu
- State Key Laboratory of Geobiology and Environmental Geology, China University of Geosciences, Wuhan, P. R. China
- School of Environmental Studies, China University of Geosciences, Wuhan, P. R. China
| | - Chuntian Su
- CAGS/Key Laboratory of Karst Dynamics, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, P. R. China
| | - Shuangjiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, P. R. China
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Allenby A, Cunningham MR, Hillebrand-Voiculescu A, Comte JC, Doherty R, Kumaresan D. Occurrence of methane-oxidizing bacteria and methanogenic archaea in earth’s cave systems—A metagenomic analysis. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.909865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Karst ecosystems represent up to 25% of the land surface and recent studies highlight their potential role as a sink for atmospheric methane. Despite this, there is limited knowledge of the diversity and distribution of methane-oxidizing bacteria (MOB) or methanogens in karst caves and the sub-surface environment in general. Here, we performed a survey of 14 shotgun metagenomes from cave ecosystems covering a broad set of environmental conditions, to compare the relative abundance and phylogenetic diversity of MOB and methanogens, targeting biomarker genes for methane monooxygenase (pmoA and mmoX) and methyl-coenzyme M reductase (mcrA). Taxonomic analysis of metagenomes showed 0.02–1.28% of classified reads were related to known MOB, of which Gammaproteobacterial MOB were the most abundant making up on average 70% of the surveyed caves’ MOB community. Potential for biogenic methane production in caves was also observed, with 0.008–0.39% of reads classified to methanogens and was dominated by sequences related to Methanosarcina. We have also generated a cave ecosystems protein database (CEPD) based on protein level assembly of cave metagenomes that can be used to profile genes of interest.
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Diversity and Composition of Methanotroph Communities in Caves. Microbiol Spectr 2022; 10:e0156621. [PMID: 35943259 PMCID: PMC9430973 DOI: 10.1128/spectrum.01566-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Methane oxidizing microorganisms (methanotrophs) are ubiquitous in the environment and represent a major sink for the greenhouse gas methane (CH4). Recent studies have demonstrated methanotrophs are abundant and contribute to CH4 dynamics in caves. However, very little is known about what controls the distribution and abundance of methanotrophs in subterranean ecosystems. Here, we report a survey of soils collected from > 20 caves in North America to elucidate the factors shaping cave methanotroph communities. Using 16S rRNA sequencing, we recovered methanotrophs from nearly all (98%) of the samples, including cave sites where CH4 concentrations were at or below detection limits (≤0.3 ppmv). We identified a core methanotroph community among caves comprised of high-affinity methanotrophs. Although associated with local-scale mineralogy, methanotroph composition did not systematically vary between the entrances and interior of caves, where CH4 concentrations varied. We also observed methanotrophs are able to disperse readily between cave systems showing these organisms have low barriers to dispersal. Lastly, the relative abundance of methanotrophs was positively correlated with cave-air CH4 concentrations, suggesting these microorganisms contribute to CH4 flux in subterranean ecosystems. IMPORTANCE Recent observations have shown the atmospheric greenhouse gas methane (CH4) is consumed by microorganisms (methanotrophs) in caves at rates comparable to CH4 oxidation in surface soils. Caves are abundant in karst landscapes that comprise 14% of Earth’s land surface area, and therefore may represent a potentially important, but overlooked, CH4 sink. We sampled cave soils to gain a better understand the community composition and structure of cave methanotrophs. Our results show the members of the USC-γ clade are dominant in cave communities and can easily disperse through the environment, methanotroph relative abundance was correlated with local scale mineralogy of soils, and the relative abundance of methanotrophs was positively correlated with CH4 concentrations in cave air.
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Martin-Pozas T, Cuezva S, Fernandez-Cortes A, Cañaveras JC, Benavente D, Jurado V, Saiz-Jimenez C, Janssens I, Seijas N, Sanchez-Moral S. Role of subterranean microbiota in the carbon cycle and greenhouse gas dynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154921. [PMID: 35364174 DOI: 10.1016/j.scitotenv.2022.154921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/15/2022] [Accepted: 03/26/2022] [Indexed: 06/14/2023]
Abstract
Subterranean ecosystems play an active role in the global carbon cycle, yet only a few studies using indirect methods have focused on the role of the cave microbiota in this critical cycle. Here we present pioneering research based on in situ real-time monitoring of CO2 and CH4 diffusive fluxes and concurrent δ13C geochemical tracing in caves, combined with 16S microbiome analysis. Our findings show that cave sediments are promoting continuous CH4 consumption from cave atmosphere, resulting in a significant removal of 65% to 90%. This research reveals the most effective taxa and metabolic pathways in consumption and uptake of greenhouse gases. Methanotrophic bacteria were the most effective group involved in CH4 consumption, namely within the families Methylomonaceae, Methylomirabilaceae and Methylacidiphilaceae. In addition, Crossiella and Nitrosococcaceae wb1-P19 could be one of the main responsible of CO2 uptake, which occurs via the Calvin-Benson-Bassham cycle and reversible hydration of CO2. Thus, syntrophic relationships exist between Crossiella and nitrifying bacteria that capture CO2, consume inorganic N produced by heterotrophic ammonification in the surface of sediments, and induce moonmilk formation. Moonmilk is found as the most evolved phase of the microbial processes in cave sediments that fixes CO2 as calcite and intensifies CH4 oxidation. From an ecological perspective, cave sediments act qualitatively as soils, providing fundamental ecosystem services (e.g. nutrient cycling and carbon sequestration) with direct influence on greenhouse gas emissions.
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Affiliation(s)
- Tamara Martin-Pozas
- Department of Geology, National Museum of Natural Sciences (MNCN-CSIC), 28006 Madrid, Spain.
| | - Soledad Cuezva
- Department of Geology, Geography and Environment, University of Alcalá, Scientific Technological Campus, 28802 Alcalá de Henares, Spain; Plants and Ecosystems, Department of Biology, University of Antwerp, 2610 Wilrijk, Belgium.
| | | | - Juan Carlos Cañaveras
- Department of Environmental and Earth Sciences, University of Alicante, San Vicente del Raspeig Campus, 03690 Alicante, Spain.
| | - David Benavente
- Department of Environmental and Earth Sciences, University of Alicante, San Vicente del Raspeig Campus, 03690 Alicante, Spain.
| | - Valme Jurado
- Department of Agrochemistry, Environmental Microbiology and Soil Conservation, Institute of Natural Resources and Agricultural Biology (IRNAS-CSIC), 41012 Seville, Spain.
| | - Cesareo Saiz-Jimenez
- Department of Agrochemistry, Environmental Microbiology and Soil Conservation, Institute of Natural Resources and Agricultural Biology (IRNAS-CSIC), 41012 Seville, Spain.
| | - Ivan Janssens
- Plants and Ecosystems, Department of Biology, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Naomi Seijas
- Department of Geology, National Museum of Natural Sciences (MNCN-CSIC), 28006 Madrid, Spain.
| | - Sergio Sanchez-Moral
- Department of Geology, National Museum of Natural Sciences (MNCN-CSIC), 28006 Madrid, Spain.
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7
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Sanchez-Moral S, Jurado V, Fernandez-Cortes A, Cuezva S, Martin-Pozas T, Gonzalez-Pimentel JL, Ontañon R, Saiz-Jimenez C. Environment-driven control of fungi in subterranean ecosystems: the case of La Garma Cave (northern Spain). Int Microbiol 2021; 24:573-591. [PMID: 34292448 PMCID: PMC8616876 DOI: 10.1007/s10123-021-00193-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/02/2021] [Accepted: 07/01/2021] [Indexed: 11/24/2022]
Abstract
Airborne microorganisms can cause important conservation problems in caves with Paleolithic art and therefore the knowledge of cave aerodynamic is essential. La Garma Cave (Cantabria, Spain), an exceptional archaeological site with several levels of galleries interconnected and two entrances, presents a complex atmospheric dynamics. An approach including aerobiological sampling together with microclimate monitoring was applied to assess the factors controlling the origin of airborne fungi. Here we show that winter ventilation is critical for the increasing of Basidiomycota spores in the cave air and the highest concentrations were found in the most ventilated areas. On the contrary, Ascomycota spores prevailed in absence of ventilation. Besides, most Ascomycota were linked to insects and bats that visit or inhabit the cave. The combination of aerobiological and microclimate data constitutes a good approach to evaluate the influence of external climatic conditions and design the most suitable strategies for the conservation of cultural heritage in the cave environment.
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Affiliation(s)
| | - Valme Jurado
- Instituto de Recursos Naturales y Agrobiologia (IRNAS-CSIC), 41012, Sevilla, Spain
| | | | - Soledad Cuezva
- Departamento de Geologia, Geografia y Ciencias Ambientales, Universidad de Alcala de Henares, 28805, Madrid, Spain
| | | | | | - Roberto Ontañon
- Museo de Prehistoria y Arqueologia de Cantabria, 39009, Santander, Spain
| | - Cesareo Saiz-Jimenez
- Instituto de Recursos Naturales y Agrobiologia (IRNAS-CSIC), 41012, Sevilla, Spain.
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8
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Lukoseviciute L, Lebedeva J, Kuisiene N. Diversity of Polyketide Synthases and Nonribosomal Peptide Synthetases Revealed Through Metagenomic Analysis of a Deep Oligotrophic Cave. MICROBIAL ECOLOGY 2021; 81:110-121. [PMID: 32638044 DOI: 10.1007/s00248-020-01554-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Caves are considered to be extreme and challenging environments. It is believed that the ability of microorganisms to produce secondary metabolites enhances their survivability and adaptiveness in the energy-starved cave environment. Unfortunately, information on the genetic potential for the production of secondary metabolites, such as polyketides and nonribosomal peptides, is limited. In the present study, we aimed to identify and characterize genes responsible for the production of secondary metabolites in the microbial community of one of the deepest caves in the world, Krubera-Voronja Cave (43.4184 N 40.3083 E, Western Caucasus). The analysed sample materials included sediments, drinkable water from underground camps, soil and clay from the cave walls, speleothems and coloured spots from the cave walls. The type II polyketide synthases (PKSs) ketosynthases α and β and the adenylation domains of nonribosomal peptide synthetases (NRPSs) were investigated using a metagenomic approach. Taxonomic diversity analysis showed that most PKS sequences could be attributed to Actinobacteria followed by unclassified bacteria and Acidobacteria, while the NRPS sequences were more taxonomically diverse and could be assigned to Proteobacteria, Actinobacteria, Cyanobacteria, Firmicutes, Chloroflexi, etc. Only three putative metabolites could be predicted: an angucycline group polyketide, a massetolide A-like cyclic lipopeptide and a surfactin-like lipopeptide. The absolute majority of PKS and NRPS sequences showed low similarity with the sequences of the reference biosynthetic pathways, suggesting that these sequences could be involved in the production of novel secondary metabolites.
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Affiliation(s)
- Laima Lukoseviciute
- Department of Microbiology and Biotechnology, Institute of Biosciences, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Jolanta Lebedeva
- Department of Microbiology and Biotechnology, Institute of Biosciences, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Nomeda Kuisiene
- Department of Microbiology and Biotechnology, Institute of Biosciences, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
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Martin-Pozas T, Sanchez-Moral S, Cuezva S, Jurado V, Saiz-Jimenez C, Perez-Lopez R, Carrey R, Otero N, Giesemann A, Well R, Calaforra JM, Fernandez-Cortes A. Biologically mediated release of endogenous N 2O and NO 2 gases in a hydrothermal, hypoxic subterranean environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 747:141218. [PMID: 32777502 DOI: 10.1016/j.scitotenv.2020.141218] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/17/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
The migration of geogenic gases in continental areas with geothermal activity and active faults is an important process releasing greenhouse gases (GHG) to the lower troposphere. In this respect, caves in hypogenic environments are natural laboratories to study the compositional evolution of deep-endogenous fluids through the Critical Zone. Vapour Cave (Alhama, Murcia, Spain) is a hypogenic cave formed by the upwelling of hydrothermal CO2-rich fluids. Anomalous concentrations of N2O and NO2 were registered in the cave's subterranean atmosphere, averaging ten and five times the typical atmospheric backgrounds, respectively. We characterised the thermal conditions, gaseous compositions, sediments, and microbial communities at different depths in the cave. We did so to understand the relation between N-cycling microbial groups and the production and transformation of nitrogenous gases, as well as their coupled evolution with CO2 and CH4 during their migration through the Critical Zone to the lower troposphere. Our results showed an evident vertical stratification of selected microbial groups (Archaea and Bacteria) depending on the environmental parameters, including O2, temperature, and GHG concentration. Both the N2O isotope ratios and the predicted ecological functions of bacterial and archaeal communities suggest that N2O and NO2 emissions mainly depend on the nitrification by ammonia-oxidising microorganisms. Denitrification and abiotic reactions of the reactive intermediates NH2OH, NO, and NO2- are also plausible according to the results of the phylogenetic analyses of the microbial communities. Nitrite-dependent anaerobic methane oxidation by denitrifying methanotrophs of the NC10 phylum was also identified as a post-genetic process during migration of this gas to the surface. To the best of our knowledge, our report provides, for the first time, evidence of a niche densely populated by Micrarchaeia, which represents more than 50% of the total archaeal abundance. This raises many questions on the metabolic behaviour of this and other archaeal phyla.
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Affiliation(s)
- Tamara Martin-Pozas
- Department of Geology, National Museum of Natural Sciences (MNCN-CSIC), 28006 Madrid, Spain.
| | - Sergio Sanchez-Moral
- Department of Geology, National Museum of Natural Sciences (MNCN-CSIC), 28006 Madrid, Spain.
| | - Soledad Cuezva
- Plants and Ecosystems, Department of Biology, University of Antwerp, 2610 Wilrijk, Belgium.
| | - Valme Jurado
- Department of Agrochemistry, Environmental Microbiology and Soil Conservation, Institute of Natural Resources and Agricultural Biology (IRNAS-CSIC), 41012 Seville, Spain.
| | - Cesareo Saiz-Jimenez
- Department of Agrochemistry, Environmental Microbiology and Soil Conservation, Institute of Natural Resources and Agricultural Biology (IRNAS-CSIC), 41012 Seville, Spain.
| | - Raul Perez-Lopez
- Geological Hazard Division, Geological Survey of Spain (IGME), 28003 Madrid, Spain.
| | - Raul Carrey
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), 08028 Barcelona, Spain; Institut de Recerca de l'Aigua (IdRA), UB, 08001 Barcelona, Spain.
| | - Neus Otero
- Grup MAiMA, SGR Mineralogia Aplicada, Geoquímica i Geomicrobiologia, Departament de Mineralogia, Petrologia i Geologia Aplicada, Facultat de Ciències de la Terra, Universitat de Barcelona (UB), 08028 Barcelona, Spain; Institut de Recerca de l'Aigua (IdRA), UB, 08001 Barcelona, Spain.
| | - Anette Giesemann
- Thünen Institute of Climate-Smart Agriculture, Federal Research Institute for Rural Areas, Forestry and Fisheries, 38116 Braunschweig, Germany.
| | - Reinhard Well
- Thünen Institute of Climate-Smart Agriculture, Federal Research Institute for Rural Areas, Forestry and Fisheries, 38116 Braunschweig, Germany.
| | - Jose M Calaforra
- Department of Biology and Geology, University of Almeria, 04120 Almeria, Spain.
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Cai Y, Zhou X, Shi L, Jia Z. Atmospheric Methane Oxidizers Are Dominated by Upland Soil Cluster Alpha in 20 Forest Soils of China. MICROBIAL ECOLOGY 2020; 80:859-871. [PMID: 32803363 DOI: 10.1007/s00248-020-01570-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 08/03/2020] [Indexed: 05/25/2023]
Abstract
Upland soil clusters alpha and gamma (USCα and USCγ) are considered a major biological sink of atmospheric methane and are often detected in forest and grassland soils. These clusters are phylogenetically classified using the particulate methane monooxygenase gene pmoA because of the difficulty of cultivation. Recent studies have established a direct link of pmoA genes to 16S rRNA genes based on their isolated strain or draft genomes. However, whether the results of pmoA-based assays could be largely represented by 16S rRNA gene sequencing in upland soils remains unclear. In this study, we collected 20 forest soils across China and compared methane-oxidizing bacterial (MOB) communities by high-throughput sequencing of 16S rRNA and pmoA genes using different primer sets. The results showed that 16S rRNA gene sequencing and the semi-nested polymerase chain reaction (PCR) of the pmoA gene (A189/A682r nested with a mixture of mb661 and A650) consistently revealed the dominance of USCα (accounting for more than 50% of the total MOB) in 12 forest soils. A189f/A682r successfully amplified pmoA genes (mainly RA14 of USCα) in only three forest soils. A189f/mb661 could amplify USCα (mainly JR1) in several forest soils but showed a strong preferential amplification of Methylocystis and many other type I MOB groups. A189f/A650 almost exclusively amplified USCα (mainly JR1) and largely discriminated against Methylocystis and most of the other MOB groups. The semi-nested PCR approach weakened the bias of A189f/mb661 and A189f/A650 for JR1 and balanced the coverage of all USCα members. The canonical correspondence analysis indicated that soil NH4+-N and pH were the main environmental factors affecting the MOB community of Chinese forest soils. The RA14 of the USCα group prefers to live in soils with low pH, low temperature, low elevation, high precipitation, and rich in nitrogen. JR1's preferences for temperature and elevation were opposite to RA14. Our study suggests that combining the deep sequencing of 16S rRNA and pmoA genes to characterize MOB in forest soils is the best choice.
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Affiliation(s)
- Yuanfeng Cai
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, China
| | - Xue Zhou
- College of agricultural science and engineering, Hohai University, Nanjing, 210098, Jiangsu Province, China
| | - Limei Shi
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, China
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, Jiangsu Province, China.
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Zhao R, Wang H, Cheng X, Yun Y, Qiu X. Upland soil cluster γ dominates the methanotroph communities in the karst Heshang Cave. FEMS Microbiol Ecol 2019; 94:5107866. [PMID: 30265314 DOI: 10.1093/femsec/fiy192] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/26/2018] [Indexed: 11/13/2022] Open
Abstract
Microorganisms are thought to play a critical role in methane (CH4) consumption in karst caves and yet the presence and diversity of methane-oxidizing bacteria (MOB) remain a mystery. In Heshang Cave, CH4 concentration decreases from 1.9 ppm at the entrance to 0.65 ppm inside the cave. To explore the presence and diversity of MOB in this cave, weathered rocks and sediment samples were collected from the cave and subjected to molecular analysis. The abundances of MOB were 107-108 copies g-1 dry sample via quantification of the pmoA gene, which are comparable to or even higher than those reported in other terrestrial environments, and account for up to 20% of the total microbial communities. Phylogenetically, MOB communities were dominated by the 'high-affinity' upland soil cluster γ (USCγ), although the predominance of Type Ia MOB was also detected in the permanently waterlogged stream sediment. The estimated CH4 oxidation potential varied dramatically among samples in the range of 0.6-80 CH4 m-3 d-1. Collectively, this study provides compelling evidence that the high-affinity MOB capable of oxidizing CH4 at the atmospheric level are present in Heshang Cave, which may play an important role in the CH4 consumption, and supports karst caves as important atmospheric CH4 sinks.
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Affiliation(s)
- Rui Zhao
- State Key Laboratory of Biogeology and Environment Geology, China University of Geosciences, Wuhan 430074, P. R. China.,Now at School of Marine Science and Policy, University of Delaware, Lewes 19958, Delaware, USA
| | - Hongmei Wang
- State Key Laboratory of Biogeology and Environment Geology, China University of Geosciences, Wuhan 430074, P. R. China.,Laboratory of Basin Hydrology and Wetland Eco-restoration, China University of Geosciences, Wuhan, 430074, P. R. China
| | - Xiaoyu Cheng
- State Key Laboratory of Biogeology and Environment Geology, China University of Geosciences, Wuhan 430074, P. R. China
| | - Yuan Yun
- State Key Laboratory of Biogeology and Environment Geology, China University of Geosciences, Wuhan 430074, P. R. China
| | - Xuan Qiu
- State Key Laboratory of Biogeology and Environment Geology, China University of Geosciences, Wuhan 430074, P. R. China
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Wiseschart A, Mhuantong W, Tangphatsornruang S, Chantasingh D, Pootanakit K. Shotgun metagenomic sequencing from Manao-Pee cave, Thailand, reveals insight into the microbial community structure and its metabolic potential. BMC Microbiol 2019; 19:144. [PMID: 31248378 PMCID: PMC6598295 DOI: 10.1186/s12866-019-1521-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 06/19/2019] [Indexed: 12/21/2022] Open
Abstract
Background Due to the cave oligotrophic environment, this habitat presents a challenge for microorganisms to colonize and thrive. However, it has been well documented that microorganisms play important roles in cave development. Survival of microbes in this unique habitat likely involves a broad range of adaptive capabilities. Recently, cave microbiomes all over the world are of great scientific interest. However, the majority of investigations focused mostly on small subunit ribosomal RNA (16S rRNA) gene, leaving the ecological role of the microbial community largely unknown. Here, we are particularly interested in exploring the taxonomic composition and metabolic potential of microorganisms in soil from Manao-Pee cave, a subterranean limestone cave in the western part of Thailand, by using high-throughput shotgun metagenomic sequencing. Results From taxonomic composition analysis using ribosomal RNA genes (rRNA), the results confirmed that Actinobacteria (51.2%) and Gammaproteobacteria (24.4%) were the dominant bacterial groups in the cave soil community. Metabolic potential analysis, based on six functional modules of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, revealed that functional genes involved in microbial metabolisms are highly represented in this community (40.6%). To better understand how microbes thrive under unfavorable cave condition, we focused on microbial energy metabolism. The results showed that microbial genes involved in oxidative phosphorylation were the most dominant (28.8%) in Manao-Pee cave, and were followed by methane metabolism (20.5%), carbon fixation (16.0%), nitrogen metabolism (14.7%), and sulfur metabolism (6.3%). In addition, microbial genes involved in xenobiotic biodegradation (26 pathways) and in production of secondary metabolites (27 pathways) were also identified. Conclusion In addition to providing information on microbial diversity, we also gained insights into microbial adaptations and survival strategies under cave conditions. Based on rRNA genes, the results revealed that bacteria belonging to the Actinobacteria and Gammaproteobacteria were the most abundant in this community. From metabolic potential analysis, energy and nutrient sources that sustain diverse microbial population in this community might be atmospheric gases (methane, carbon dioxide, nitrogen), inorganic sulfur, and xenobiotic compounds. In addition, the presence of biosynthetic pathways of secondary metabolites suggested that they might play important ecological roles in the cave microbiome. Electronic supplementary material The online version of this article (10.1186/s12866-019-1521-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Apirak Wiseschart
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phuttamonthon 4 Rd, Salaya, Nakhon Pathom, 73170, Thailand
| | - Wuttichai Mhuantong
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 133 Thailand Science Park, Paholyothin Rd, Klong 1, Klongluang, Pathumthani, 12120, Thailand
| | - Sithichoke Tangphatsornruang
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 133 Thailand Science Park, Paholyothin Rd, Klong 1, Klongluang, Pathumthani, 12120, Thailand
| | - Duriya Chantasingh
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 133 Thailand Science Park, Paholyothin Rd, Klong 1, Klongluang, Pathumthani, 12120, Thailand
| | - Kusol Pootanakit
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phuttamonthon 4 Rd, Salaya, Nakhon Pathom, 73170, Thailand.
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Bodelier PLE, Pérez G, Veraart AJ, Krause SMB. Methanotroph Ecology, Environmental Distribution and Functioning. METHANOTROPHS 2019. [DOI: 10.1007/978-3-030-23261-0_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Schimmelmann A, Fernandez-Cortes A, Cuezva S, Streil T, Lennon JT. Radiolysis via radioactivity is not responsible for rapid methane oxidation in subterranean air. PLoS One 2018; 13:e0206506. [PMID: 30383783 PMCID: PMC6211692 DOI: 10.1371/journal.pone.0206506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 10/15/2018] [Indexed: 11/18/2022] Open
Abstract
Atmospheric methane is rapidly lost when it enters humid subterranean critical and vadose zones (e.g., air in soils and caves). Because methane is a source of carbon and energy, it can be consumed by methanotrophic methane-oxidizing bacteria. As an additional subterranean sink, it has been hypothesized that methane is oxidized by natural radioactivity-induced radiolysis that produces energetic ions and radicals, which then trigger abiotic oxidation and consumption of methane within a few hours. Using controlled laboratory experiments, we tested whether radiolysis could rapidly oxidize methane in sealed air with different relative humidities while being exposed to elevated levels of radiation (more than 535 kBq m-3) from radon isotopes 222Rn and 220Rn (i.e., thoron). We found no evidence that radiolysis contributed to methane oxidation. In contrast, we observed the rapid loss of methane when moist soil was added to the same apparatus in the absence of elevated radon abundance. Together, our findings are consistent with the view that methane oxidizing bacteria are responsible for the widespread observations of methane depletion in subterranean environments. Further studies are needed on the ability of microbes to consume trace amounts of methane in poorly ventilated caves, even though the trophic and energetic benefits become marginal at very low partial pressures of methane.
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Affiliation(s)
- Arndt Schimmelmann
- Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
| | - Angel Fernandez-Cortes
- Department of Biology and Geology, University of Almeria, Almeria, Spain
- Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey, United Kingdom
| | - Soledad Cuezva
- Department of Biology and Geology, University of Almeria, Almeria, Spain
| | | | - Jay T. Lennon
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
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Pratscher J, Vollmers J, Wiegand S, Dumont MG, Kaster AK. Unravelling the Identity, Metabolic Potential and Global Biogeography of the Atmospheric Methane-Oxidizing Upland Soil Cluster α. Environ Microbiol 2018; 20:1016-1029. [PMID: 29314604 PMCID: PMC6849597 DOI: 10.1111/1462-2920.14036] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023]
Abstract
Understanding of global methane sources and sinks is a prerequisite for the design of strategies to counteract global warming. Microbial methane oxidation in soils represents the largest biological sink for atmospheric methane. However, still very little is known about the identity, metabolic properties and distribution of the microbial group proposed to be responsible for most of this uptake, the uncultivated upland soil cluster α (USCα). Here, we reconstructed a draft genome of USCα from a combination of targeted cell sorting and metagenomes from forest soil, providing the first insights into its metabolic potential and environmental adaptation strategies. The 16S rRNA gene sequence recovered was distinctive and suggests this crucial group as a new genus within the Beijerinckiaceae, close to Methylocapsa. Application of a fluorescently labelled suicide substrate for the particulate methane monooxygenase enzyme (pMMO) coupled to 16S rRNA fluorescence in situ hybridisation (FISH) allowed for the first time a direct link of the high‐affinity activity of methane oxidation to USCα cells in situ. Analysis of the global biogeography of this group further revealed its presence in previously unrecognized habitats, such as subterranean and volcanic biofilm environments, indicating a potential role of these environments in the biological sink for atmospheric methane.
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Affiliation(s)
| | - John Vollmers
- Institute for Biological Interfaces (IBG5), Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Sandra Wiegand
- Department of Microbiology, Institute for Water and Wetland Research, Faculty of Science, Radboud University, Nijmegen, The Netherlands
| | - Marc G Dumont
- Biological Sciences, University of Southampton, Southampton, UK
| | - Anne-Kristin Kaster
- Institute for Biological Interfaces (IBG5), Karlsruhe Institute of Technology, Karlsruhe, Germany
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