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Konya K, Sueyoshi T, Iwahana G, Morishita T, Uetake J, Wakita M. CH 4 emissions from runoff water of Alaskan mountain glaciers. Sci Rep 2024; 14:10558. [PMID: 38724590 PMCID: PMC11082196 DOI: 10.1038/s41598-024-56608-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 03/08/2024] [Indexed: 05/12/2024] Open
Abstract
Recent studies have observed high methane concentrations in runoff water and the ambient air at various glacier sites, including the Greenland Ice Sheet, the glacier forefield in Svalbard, and the ice cap in Iceland. This study extends these findings to smaller mountain glaciers in Alaska. Methane and carbon dioxide concentrations in the ambient air near the meltwater outlet, fluxes of these gases at the surface of runoff water and riverbank sediments, and dissolved methane content in the runoff water were measured at four glaciers. Three of the four glaciers showed conspicuous signals of methane emissions from runoff water, with the Castner Glacier terminus exhibiting a methane concentration three times higher than background levels, along with elevated dissolved methane levels in the runoff water. This study marks the detection of significant methane emissions from small mountain glacier runoff, contributing to the understanding that mountain glaciers also release methane into the atmosphere.
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Affiliation(s)
- Keiko Konya
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, 236-0001, Japan
| | - Tetsuo Sueyoshi
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, 236-0001, Japan.
- National Institute of Polar Research, Tachikawa, 190-8518, Japan.
| | - Go Iwahana
- International Arctic Research Center (IARC), University of Alaska, Fairbanks (UAF), Fairbanks, 99775, USA
| | - Tomoaki Morishita
- Tohoku Research Center, Forestry and Forest Products Research Institute (FFPRI), Morioka, 020-0123, Japan
| | - Jun Uetake
- Hokkaido University, Field Science Center for Northern Biosphere, Tomakomai, 053-0035, Japan
| | - Masahide Wakita
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Mutsu, 035-0022, Japan
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2
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Znamínko M, Falteisek L, Vrbická K, Klímová P, Christiansen JR, Jørgensen CJ, Stibal M. Methylotrophic Communities Associated with a Greenland Ice Sheet Methane Release Hotspot. MICROBIAL ECOLOGY 2023; 86:3057-3067. [PMID: 37843656 PMCID: PMC10640400 DOI: 10.1007/s00248-023-02302-x] [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: 04/04/2023] [Accepted: 09/09/2023] [Indexed: 10/17/2023]
Abstract
Subglacial environments provide conditions suitable for the microbial production of methane, an important greenhouse gas, which can be released from beneath the ice as a result of glacial melting. High gaseous methane emissions have recently been discovered at Russell Glacier, an outlet of the southwestern margin of the Greenland Ice Sheet, acting not only as a potential climate amplifier but also as a substrate for methane consuming microorganisms. Here, we describe the composition of the microbial assemblage exported in meltwater from the methane release hotspot at Russell Glacier and its changes over the melt season and as it travels downstream. We found that a substantial part (relative abundance 27.2% across the whole dataset) of the exported assemblage was made up of methylotrophs and that the relative abundance of methylotrophs increased as the melt season progressed, likely due to the seasonal development of the glacial drainage system. The methylotrophs were dominated by representatives of type I methanotrophs from the Gammaproteobacteria; however, their relative abundance decreased with increasing distance from the ice margin at the expense of type II methanotrophs and/or methylotrophs from the Alphaproteobacteria and Betaproteobacteria. Our results show that subglacial methane release hotspot sites can be colonized by microorganisms that can potentially reduce methane emissions.
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Affiliation(s)
- Matěj Znamínko
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia.
- Current address: Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland.
| | - Lukáš Falteisek
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Kristýna Vrbická
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Petra Klímová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Jesper R Christiansen
- Department of Geoscience and Natural Resource Management, University of Copenhagen, Copenhagen, Denmark
| | | | - Marek Stibal
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia.
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3
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Řezanka T, Kyselová L, Murphy DJ. Archaeal lipids. Prog Lipid Res 2023; 91:101237. [PMID: 37236370 DOI: 10.1016/j.plipres.2023.101237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/25/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023]
Abstract
The major archaeal membrane glycerolipids are distinguished from those of bacteria and eukaryotes by the contrasting stereochemistry of their glycerol backbones, and by the use of ether-linked isoprenoid-based alkyl chains rather than ester-linked fatty acyl chains for their hydrophobic moieties. These fascinating compounds play important roles in the extremophile lifestyles of many species, but are also present in the growing numbers of recently discovered mesophilic archaea. The past decade has witnessed significant advances in our understanding of archaea in general and their lipids in particular. Much of the new information has come from the ability to screen large microbial populations via environmental metagenomics, which has revolutionised our understanding of the extent of archaeal biodiversity that is coupled with a strict conservation of their membrane lipid compositions. Significant additional progress has come from new culturing and analytical techniques that are gradually enabling archaeal physiology and biochemistry to be studied in real time. These studies are beginning to shed light on the much-discussed and still-controversial process of eukaryogenesis, which probably involved both bacterial and archaeal progenitors. Puzzlingly, although eukaryotes retain many attributes of their putative archaeal ancestors, their lipid compositions only reflect their bacterial progenitors. Finally, elucidation of archaeal lipids and their metabolic pathways have revealed potentially interesting applications that have opened up new frontiers for biotechnological exploitation of these organisms. This review is concerned with the analysis, structure, function, evolution and biotechnology of archaeal lipids and their associated metabolic pathways.
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Affiliation(s)
- Tomáš Řezanka
- Institute of Microbiology, Czech Academy of Sciences, Vídeňská 1083, 142 00 Prague, Czech Republic
| | - Lucie Kyselová
- Research Institute of Brewing and Malting, Lípová 511, 120 44 Prague, Czech Republic
| | - Denis J Murphy
- School of Applied Sciences, University of South Wales, Pontypridd, CF37 1DL, United Kingdom.
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4
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Prondzinsky P, Toyoda S, McGlynn SE. The methanogen core and pangenome: conservation and variability across biology's growth temperature extremes. DNA Res 2022; 30:6862058. [PMID: 36454681 PMCID: PMC9886072 DOI: 10.1093/dnares/dsac048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/09/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
Temperature is a key variable in biological processes. However, a complete understanding of biological temperature adaptation is lacking, in part because of the unique constraints among different evolutionary lineages and physiological groups. Here we compared the genomes of cultivated psychrotolerant and thermotolerant methanogens, which are physiologically related and span growth temperatures from -2.5°C to 122°C. Despite being phylogenetically distributed amongst three phyla in the archaea, the genomic core of cultivated methanogens comprises about one-third of a given genome, while the genome fraction shared by any two organisms decreases with increasing phylogenetic distance between them. Increased methanogenic growth temperature is associated with reduced genome size, and thermotolerant organisms-which are distributed across the archaeal tree-have larger core genome fractions, suggesting that genome size is governed by temperature rather than phylogeny. Thermotolerant methanogens are enriched in metal and other transporters, and psychrotolerant methanogens are enriched in proteins related to structure and motility. Observed amino acid compositional differences between temperature groups include proteome charge, polarity and unfolding entropy. Our results suggest that in the methanogens, shared physiology maintains a large, conserved genomic core even across large phylogenetic distances and biology's temperature extremes.
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Affiliation(s)
- Paula Prondzinsky
- To whom correspondence should be addressed. Tel: +81 3 5734 3154. Fax: +81 3 5734 3416. (P.P.); (S.E.M.)
| | - Sakae Toyoda
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, 226-8503 Yokohama, Japan
| | - Shawn Erin McGlynn
- To whom correspondence should be addressed. Tel: +81 3 5734 3154. Fax: +81 3 5734 3416. (P.P.); (S.E.M.)
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5
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Vrbická K, Kohler TJ, Falteisek L, Hawkings JR, Vinšová P, Bulínová M, Lamarche-Gagnon G, Hofer S, Kellerman AM, Holt AD, Cameron KA, Schön M, Wadham JL, Stibal M. Catchment characteristics and seasonality control the composition of microbial assemblages exported from three outlet glaciers of the Greenland Ice Sheet. Front Microbiol 2022; 13:1035197. [PMID: 36523833 PMCID: PMC9745319 DOI: 10.3389/fmicb.2022.1035197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/09/2022] [Indexed: 10/17/2023] Open
Abstract
Glacial meltwater drains into proglacial rivers where it interacts with the surrounding landscape, collecting microbial cells as it travels downstream. Characterizing the composition of the resulting microbial assemblages in transport can inform us about intra-annual changes in meltwater flowpaths beneath the glacier as well as hydrological connectivity with proglacial areas. Here, we investigated how the structure of suspended microbial assemblages evolves over the course of a melt season for three proglacial catchments of the Greenland Ice Sheet (GrIS), reasoning that differences in glacier size and the proportion of glacierized versus non-glacierized catchment areas will influence both the identity and relative abundance of microbial taxa in transport. Streamwater samples were taken at the same time each day over a period of 3 weeks (summer 2018) to identify temporal patterns in microbial assemblages for three outlet glaciers of the GrIS, which differed in glacier size (smallest to largest; Russell, Leverett, and Isunnguata Sermia [IS]) and their glacierized: proglacial catchment area ratio (Leverett, 76; Isunnguata Sermia, 25; Russell, 2). DNA was extracted from samples, and 16S rRNA gene amplicons sequenced to characterize the structure of assemblages. We found that microbial diversity was significantly greater in Isunnguata Sermia and Russell Glacier rivers compared to Leverett Glacier, the latter of which having the smallest relative proglacial catchment area. Furthermore, the microbial diversity of the former two catchments continued to increase over monitored period, presumably due to increasing hydrologic connectivity with proglacial habitats. Meanwhile, diversity decreased over the monitored period in Leverett, which may have resulted from the evolution of an efficient subglacial drainage system. Linear discriminant analysis further revealed that bacteria characteristic to soils were disproportionately represented in the Isunnguata Sermia river, while putative methylotrophs were disproportionately abundant in Russell Glacier. Meanwhile, taxa typical for glacierized habitats (i.e., Rhodoferax and Polaromonas) dominated in the Leverett Glacier river. Our findings suggest that the proportion of deglaciated catchment area is more influential to suspended microbial assemblage structure than absolute glacier size, and improve our understanding of hydrological flowpaths, particulate entrainment, and transport.
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Affiliation(s)
- Kristýna Vrbická
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Tyler J. Kohler
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
- River Ecosystems Laboratory, Alpine and Polar Environmental Research Center, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Lukáš Falteisek
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Jon R. Hawkings
- Department of Earth and Environment, University of Pennsylvania, Philadelphia, PA, United States
| | - Petra Vinšová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Marie Bulínová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
- Department of Geosciences, UiT, The Arctic University of Norway, Tromsø, Norway
| | - Guillaume Lamarche-Gagnon
- Department of Geosciences, UiT, The Arctic University of Norway, Tromsø, Norway
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
| | - Stefan Hofer
- Department of Geosciences, UiO University of Oslo, Oslo, Norway
| | - Anne M. Kellerman
- Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, United States
| | - Amy D. Holt
- Department of Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, United States
| | - Karen A. Cameron
- School of Geographical & Earth Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Martina Schön
- River Ecosystems Laboratory, Alpine and Polar Environmental Research Center, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jemma L. Wadham
- Department of Geosciences, UiT, The Arctic University of Norway, Tromsø, Norway
| | - Marek Stibal
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
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Campbell BC, Greenfield P, Gong S, Barnhart EP, Midgley DJ, Paulsen IT, George SC. Methanogenic archaea in subsurface coal seams are biogeographically distinct: an analysis of metagenomically-derived mcrA sequences. Environ Microbiol 2022; 24:4065-4078. [PMID: 35437913 PMCID: PMC9790511 DOI: 10.1111/1462-2920.16014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/08/2022] [Accepted: 04/10/2022] [Indexed: 12/30/2022]
Abstract
The production of methane as an end-product of organic matter degradation in the absence of other terminal electron acceptors is common, and has often been studied in environments such as animal guts, soils and wetlands due to its potency as a greenhouse gas. To date, however, the study of the biogeographic distribution of methanogens across coal seam environments has been minimal. Here, we show that coal seams are host to a diverse range of methanogens, which are distinctive to each geological basin. Based on comparisons to close relatives from other methanogenic environments, the dominant methanogenic pathway in these basins is hydrogenotrophic, with acetoclastic being a second major pathway in the Surat Basin. Finally, mcrA and 16S rRNA gene primer biases were predominantly seen to affect the detection of Methanocellales, Methanomicrobiales and Methanosarcinales taxa in this study. Subsurface coal methanogenic community distributions and pathways presented here provide insights into important metabolites and bacterial partners for in situ coal biodegradation.
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Affiliation(s)
- Bronwyn C. Campbell
- Energy Business UnitCommonwealth Scientific and Industrial Research Organisation (CSIRO)LindfieldNSW2070Australia,School of Natural SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | - Paul Greenfield
- Energy Business UnitCommonwealth Scientific and Industrial Research Organisation (CSIRO)LindfieldNSW2070Australia,School of Natural SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | - Se Gong
- Energy Business UnitCommonwealth Scientific and Industrial Research Organisation (CSIRO)LindfieldNSW2070Australia
| | | | - David J. Midgley
- Energy Business UnitCommonwealth Scientific and Industrial Research Organisation (CSIRO)LindfieldNSW2070Australia
| | - Ian T. Paulsen
- School of Natural SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | - Simon C. George
- School of Natural SciencesMacquarie UniversityNorth RydeNSW2109Australia
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7
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Bourquin M, Busi SB, Fodelianakis S, Peter H, Washburne A, Kohler TJ, Ezzat L, Michoud G, Wilmes P, Battin TJ. The microbiome of cryospheric ecosystems. Nat Commun 2022; 13:3087. [PMID: 35655063 PMCID: PMC9163120 DOI: 10.1038/s41467-022-30816-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 05/20/2022] [Indexed: 01/03/2023] Open
Abstract
The melting of the cryosphere is among the most conspicuous consequences of climate change, with impacts on microbial life and related biogeochemistry. However, we are missing a systematic understanding of microbiome structure and function across cryospheric ecosystems. Here, we present a global inventory of the microbiome from snow, ice, permafrost soils, and both coastal and freshwater ecosystems under glacier influence. Combining phylogenetic and taxonomic approaches, we find that these cryospheric ecosystems, despite their particularities, share a microbiome with representatives across the bacterial tree of life and apparent signatures of early and constrained radiation. In addition, we use metagenomic analyses to define the genetic repertoire of cryospheric bacteria. Our work provides a reference resource for future studies on climate change microbiology. The cryosphere includes those parts of Earth where water or soil is frozen, such as snow, ice, glaciers and permafrost soils. Here, the authors present a global inventory of cryospheric microbial communities and their genetic repertoires.
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Affiliation(s)
- Massimo Bourquin
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland.
| | - Susheel Bhanu Busi
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Campus Belval, 7, avenue des Hauts-Fourneaux, L-4362, Esch-sur-Alzette, Luxembourg
| | - Stilianos Fodelianakis
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Hannes Peter
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | | | - Tyler J Kohler
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Leïla Ezzat
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Grégoire Michoud
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland
| | - Paul Wilmes
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Campus Belval, 7, avenue des Hauts-Fourneaux, L-4362, Esch-sur-Alzette, Luxembourg.,Department of Life Sciences and Medicine, Faculty of Science, Technology and Medicine, University of Luxembourg, 7, avenue des Hauts-Fourneaux, L-4362, Esch-sur-Alzette, Luxembourg
| | - Tom J Battin
- River Ecosystems Laboratory, Centre for Alpine and Polar Environmental Research (ALPOLE), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, Switzerland.
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Abstract
The glaciers in China have an important role as one of the most climate-sensitive constituents of the Tibetan Plateau which is known as the Asian Water Tower. Although the cryosphere is one of the most extreme environments for organisms, the soils of the glacier foreland harbor surprisingly rich microbiomes. A large amount of accelerated glacier retreat accompanied by global warming will not only raise the sea level, but it will also lead to the massive release of a considerable amount of carbon stored in these glaciers. The responses of glacier microbiomes could alter the biogeochemical cycle of carbon and have a complex impact on climate change. Thus, understanding present-day and future glacier microbiome changes is crucial to assess the feedback on climate change and the impacts on ecosystems. To this end, we discuss here the diversity and biogeochemical functions of the microbiomes in Chinese mountain glacier ecosystems.
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MARTINS MATEUSDOSSANTOS, FERREIRA FABRICIO, AYRES NETO ARTHUR, VIEIRA ROSEMARY. Geophysical investigation in sediment cores and its relationship with the governing sedimentary processes at Bransfield Basin, Antarctica. AN ACAD BRAS CIENC 2022; 94:e20210551. [DOI: 10.1590/0001-3765202220210551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 09/10/2021] [Indexed: 11/22/2022] Open
Affiliation(s)
| | - FABRICIO FERREIRA
- Universidade Federal Fluminense (DOT-UFF), Brazil; Universidade Federal Fluminense/UFF, Brazil
| | | | - ROSEMARY VIEIRA
- Universidade Federal Fluminense (DOT-UFF), Brazil; Universidade Federal Fluminense/UFF, Brazil
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Dindhoria K, Kumar S, Kumar R. Taxonomic and functional analysis of proglacial water bodies of Triloknath glacier ecosystem from North-Western Himalayas. ECOL INFORM 2021. [DOI: 10.1016/j.ecoinf.2021.101365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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11
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Lavergne C, Aguilar-Muñoz P, Calle N, Thalasso F, Astorga-España MS, Sepulveda-Jauregui A, Martinez-Cruz K, Gandois L, Mansilla A, Chamy R, Barret M, Cabrol L. Temperature differently affected methanogenic pathways and microbial communities in sub-Antarctic freshwater ecosystems. ENVIRONMENT INTERNATIONAL 2021; 154:106575. [PMID: 33901975 DOI: 10.1016/j.envint.2021.106575] [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: 01/15/2021] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
Freshwater ecosystems are responsible for an important part of the methane (CH4) emissions which are likely to change with global warming. This study aims to evaluate temperature-induced (from 5 to 20 °C) changes on microbial community structure and methanogenic pathways in five sub-Antarctic lake sediments from Magallanes strait to Cape Horn, Chile. We combined in situ CH4 flux measurements, CH4 production rates (MPRs), gene abundance quantification and microbial community structure analysis (metabarcoding of the 16S rRNA gene). Under unamended conditions, a temperature increase of 5 °C doubled MPR while microbial community structure was not affected. Stimulation of methanogenesis by methanogenic precursors as acetate and H2/CO2, resulted in an increase of MPRs up to 127-fold and 19-fold, respectively, as well as an enrichment of mcrA-carriers strikingly stronger under acetate amendment. At low temperatures, H2/CO2-derived MPRs were considerably lower (down to 160-fold lower) than the acetate-derived MPRs, but the contribution of hydrogenotrophic methanogenesis increased with temperature. Temperature dependence of MPRs was significantly higher in incubations spiked with H2/CO2 (c. 1.9 eV) compared to incubations spiked with acetate or unamended (c. 0.8 eV). Temperature was not found to shape the total microbial community structure, that rather exhibited a site-specific variability among the studied lakes. However, the methanogenic archaeal community structure was driven by amended methanogenic precursors with a dominance of Methanobacterium in H2/CO2-based incubations and Methanosarcina in acetate-based incubations. We also suggested the importance of acetogenic H2-production outcompeting hydrogenotrohic methanogenesis especially at low temperatures, further supported by homoacetogen proportion in the microcosm communities. The combination of in situ-, and laboratory-based measurements and molecular approaches indicates that the hydrogenotrophic pathway may become more important with increasing temperatures than the acetoclastic pathway. In a continuously warming environment driven by climate change, such issues are crucial and may receive more attention.
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Affiliation(s)
- Céline Lavergne
- HUB AMBIENTAL UPLA, Laboratory of Aquatic Environmental Research, Centro de Estudios Avanzados, Universidad de Playa Ancha, Valparaíso, Chile; Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2085, 2340950 Valparaíso, Chile.
| | - Polette Aguilar-Muñoz
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2085, 2340950 Valparaíso, Chile
| | - Natalia Calle
- Departamento de Química, Universidad Técnica Federico Santa María, Valparaíso, Chile
| | - Frédéric Thalasso
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Departamento de Biotecnología y Bioingeniería, México, DF, Mexico
| | - Maria Soledad Astorga-España
- Departamento de Ciencias y Recursos Naturales, Universidad de Magallanes, Punta Arenas, Chile; ENBEELAB, University of Magallanes, Punta Arenas, Chile
| | - Armando Sepulveda-Jauregui
- ENBEELAB, University of Magallanes, Punta Arenas, Chile; Center for Climate and Resilience Research (CR)(2), Santiago, Chile
| | - Karla Martinez-Cruz
- Departamento de Ciencias y Recursos Naturales, Universidad de Magallanes, Punta Arenas, Chile; ENBEELAB, University of Magallanes, Punta Arenas, Chile
| | - Laure Gandois
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Andrés Mansilla
- Departamento de Ciencias y Recursos Naturales, Universidad de Magallanes, Punta Arenas, Chile
| | - Rolando Chamy
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2085, 2340950 Valparaíso, Chile
| | - Maialen Barret
- Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Léa Cabrol
- Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2085, 2340950 Valparaíso, Chile; Aix-Marseille University, Univ Toulon, CNRS, IRD, M.I.O. UM 110, Mediterranean Institute of Oceanography, Marseille, France; Institute of Ecology and Biodiversity IEB, Faculty of Sciences, Universidad de Chile, Santiago, Chile.
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Zhang Y, Kang S, Wei D, Luo X, Wang Z, Gao T. Sink or source? Methane and carbon dioxide emissions from cryoconite holes, subglacial sediments, and proglacial river runoff during intensive glacier melting on the Tibetan Plateau. FUNDAMENTAL RESEARCH 2021. [DOI: 10.1016/j.fmre.2021.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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13
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Lithogenic hydrogen supports microbial primary production in subglacial and proglacial environments. Proc Natl Acad Sci U S A 2020; 118:2007051117. [PMID: 33419920 PMCID: PMC7812807 DOI: 10.1073/pnas.2007051117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Life in environments devoid of photosynthesis, such as on early Earth or in contemporary dark subsurface ecosystems, is supported by chemical energy. How, when, and where chemical nutrients released from the geosphere fuel chemosynthetic biospheres is fundamental to understanding the distribution and diversity of life, both today and in the geologic past. Hydrogen (H2) is a potent reductant that can be generated when water interacts with reactive components of mineral surfaces such as silicate radicals and ferrous iron. Such reactive mineral surfaces are continually generated by physical comminution of bedrock by glaciers. Here, we show that dissolved H2 concentrations in meltwaters from an iron and silicate mineral-rich basaltic glacial catchment were an order of magnitude higher than those from a carbonate-dominated catchment. Consistent with higher H2 abundance, sediment microbial communities from the basaltic catchment exhibited significantly shorter lag times and faster rates of net H2 oxidation and dark carbon dioxide (CO2) fixation than those from the carbonate catchment, indicating adaptation to use H2 as a reductant in basaltic catchments. An enrichment culture of basaltic sediments provided with H2, CO2, and ferric iron produced a chemolithoautotrophic population related to Rhodoferax ferrireducens with a metabolism previously thought to be restricted to (hyper)thermophiles and acidophiles. These findings point to the importance of physical and chemical weathering processes in generating nutrients that support chemosynthetic primary production. Furthermore, they show that differences in bedrock mineral composition can influence the supplies of nutrients like H2 and, in turn, the diversity, abundance, and activity of microbial inhabitants.
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14
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Edwards A, Cameron KA, Cook JM, Debbonaire AR, Furness E, Hay MC, Rassner SM. Microbial genomics amidst the Arctic crisis. Microb Genom 2020; 6:e000375. [PMID: 32392124 PMCID: PMC7371112 DOI: 10.1099/mgen.0.000375] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/16/2020] [Indexed: 12/16/2022] Open
Abstract
The Arctic is warming - fast. Microbes in the Arctic play pivotal roles in feedbacks that magnify the impacts of Arctic change. Understanding the genome evolution, diversity and dynamics of Arctic microbes can provide insights relevant for both fundamental microbiology and interdisciplinary Arctic science. Within this synthesis, we highlight four key areas where genomic insights to the microbial dimensions of Arctic change are urgently required: the changing Arctic Ocean, greenhouse gas release from the thawing permafrost, 'biological darkening' of glacial surfaces, and human activities within the Arctic. Furthermore, we identify four principal challenges that provide opportunities for timely innovation in Arctic microbial genomics. These range from insufficient genomic data to develop unifying concepts or model organisms for Arctic microbiology to challenges in gaining authentic insights to the structure and function of low-biomass microbiota and integration of data on the causes and consequences of microbial feedbacks across scales. We contend that our insights to date on the genomics of Arctic microbes are limited in these key areas, and we identify priorities and new ways of working to help ensure microbial genomics is in the vanguard of the scientific response to the Arctic crisis.
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Affiliation(s)
- Arwyn Edwards
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Karen A. Cameron
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Joseph M. Cook
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Aliyah R. Debbonaire
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Eleanor Furness
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Melanie C. Hay
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Sara M.E. Rassner
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
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15
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Kohler TJ, Vinšová P, Falteisek L, Žárský JD, Yde JC, Hatton JE, Hawkings JR, Lamarche-Gagnon G, Hood E, Cameron KA, Stibal M. Patterns in Microbial Assemblages Exported From the Meltwater of Arctic and Sub-Arctic Glaciers. Front Microbiol 2020; 11:669. [PMID: 32351489 PMCID: PMC7174618 DOI: 10.3389/fmicb.2020.00669] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 03/24/2020] [Indexed: 01/14/2023] Open
Abstract
Meltwater streams connect the glacial cryosphere with downstream ecosystems. Dissolved and particulate matter exported from glacial ecosystems originates from contrasting supraglacial and subglacial environments, and exported microbial cells have the potential to serve as ecological and hydrological indicators for glacial ecosystem processes. Here, we compare exported microbial assemblages from the meltwater of 24 glaciers from six (sub)Arctic regions – the southwestern Greenland Ice Sheet, Qeqertarsuaq (Disko Island) in west Greenland, Iceland, Svalbard, western Norway, and southeast Alaska – differing in their lithology, catchment size, and climatic characteristics, to investigate spatial and environmental factors structuring exported meltwater assemblages. We found that 16S rRNA gene sequences of all samples were dominated by the phyla Proteobacteria, Bacteroidetes, and Actinobacteria, with Verrucomicrobia also common in Greenland localities. Clustered OTUs were largely composed of aerobic and anaerobic heterotrophs capable of degrading a wide variety of carbon substrates. A small number of OTUs dominated all assemblages, with the most abundant being from the genera Polaromonas, Methylophilus, and Nitrotoga. However, 16–32% of a region’s OTUs were unique to that region, and rare taxa revealed unique metabolic potentials and reflected differences between regions, such as the elevated relative abundances of sulfur oxidizers Sulfuricurvum sp. and Thiobacillus sp. at Svalbard sites. Meltwater alpha diversity showed a pronounced decrease with increasing latitude, and multivariate analyses of assemblages revealed significant regional clusters. Distance-based redundancy and correlation analyses further resolved associations between whole assemblages and individual OTUs with variables primarily corresponding with the sampled regions. Interestingly, some OTUs indicating specific metabolic processes were not strongly associated with corresponding meltwater characteristics (e.g., nitrification and inorganic nitrogen concentrations). Thus, while exported assemblage structure appears regionally specific, and probably reflects differences in dominant hydrological flowpaths, OTUs can also serve as indicators for more localized microbially mediated processes not captured by the traditional characterization of bulk meltwater hydrochemistry. These results collectively promote a better understanding of microbial distributions across the Arctic, as well as linkages between the terrestrial cryosphere habitats and downstream ecosystems.
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Affiliation(s)
- Tyler J Kohler
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia.,Stream Biofilm and Ecosystem Research Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Petra Vinšová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Lukáš Falteisek
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Jakub D Žárský
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Jacob C Yde
- Department of Environmental Sciences, Western Norway University of Applied Sciences, Sogndal, Norway
| | - Jade E Hatton
- School of Earth Sciences, University of Bristol, Bristol, United Kingdom
| | - Jon R Hawkings
- National High Magnetic Field Laboratory, Department of Earth, Ocean & Atmospheric Science, Florida State University, Tallahassee, FL, United States.,GFZ German Research Centre for Geosciences, Potsdam, Germany
| | | | - Eran Hood
- Department of Natural Sciences, University of Alaska Southeast, Juneau, AK, United States
| | - Karen A Cameron
- Institute of Biological, Environmental and Rural Sciences, Faculty of Earth and Life Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Marek Stibal
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
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16
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Ren Z, Martyniuk N, Oleksy IA, Swain A, Hotaling S. Ecological Stoichiometry of the Mountain Cryosphere. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00360] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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17
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Wadham JL, Hawkings JR, Tarasov L, Gregoire LJ, Spencer RGM, Gutjahr M, Ridgwell A, Kohfeld KE. Ice sheets matter for the global carbon cycle. Nat Commun 2019; 10:3567. [PMID: 31417076 PMCID: PMC6695407 DOI: 10.1038/s41467-019-11394-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 07/09/2019] [Indexed: 11/09/2022] Open
Abstract
The cycling of carbon on Earth exerts a fundamental influence upon the greenhouse gas content of the atmosphere, and hence global climate over millennia. Until recently, ice sheets were viewed as inert components of this cycle and largely disregarded in global models. Research in the past decade has transformed this view, demonstrating the existence of uniquely adapted microbial communities, high rates of biogeochemical/physical weathering in ice sheets and storage and cycling of organic carbon (>104 Pg C) and nutrients. Here we assess the active role of ice sheets in the global carbon cycle and potential ramifications of enhanced melt and ice discharge in a warming world.
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Affiliation(s)
- J L Wadham
- University of Bristol, Bristol, BS8 1TH, UK.
| | - J R Hawkings
- National High Magnetic Field Lab and Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, 32306, USA
- German Research Centre for Geosciences GFZ, 14473, Potsdam, Germany
| | - L Tarasov
- Memorial University, St. John's, NF, A1B 3X9, Canada
| | | | - R G M Spencer
- National High Magnetic Field Lab and Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | | | - A Ridgwell
- University of California, Riverside, CA, 94720, USA
| | - K E Kohfeld
- Simon Fraser University, Burnaby, BC, 8888, Canada
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18
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Direct isotopic evidence of biogenic methane production and efflux from beneath a temperate glacier. Sci Rep 2018; 8:17118. [PMID: 30459433 PMCID: PMC6244297 DOI: 10.1038/s41598-018-35253-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/18/2018] [Indexed: 11/08/2022] Open
Abstract
The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable 'cap' of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements. Here, we present direct field-based evidence of methane production and release from beneath the Icelandic glacier Sólheimajökull, where geothermal activity creates sub-oxic conditions suited to methane production and preservation along the meltwater flow path. Methane production at the glacier bed (48 tonnes per day, or 39 mM CH4 m-2 day-1), and evasion to the atmosphere from the proglacial stream (41 tonnes per day, or 32 M CH4 m-2 day-1) indicates considerable production and release to the atmosphere during the summer melt season. Isotopic signatures (-60.2‰ to -7.6‰ for δ13CCH4 and -324.3‰ to +161.1‰ for DCH4), support a biogenic signature within waters emerging from the subglacial environment. Temperate glacial methane production and release may thus be a significant and hitherto unresolved contributor of a potent greenhouse gas to the atmosphere.
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19
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First observation of direct methane emission to the atmosphere from the subglacial domain of the Greenland Ice Sheet. Sci Rep 2018; 8:16623. [PMID: 30413774 PMCID: PMC6226494 DOI: 10.1038/s41598-018-35054-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 10/30/2018] [Indexed: 11/08/2022] Open
Abstract
During a 2016 field expedition to the West Greenland Ice Sheet, a striking observation of significantly elevated CH4 concentrations of up to 15 times the background atmospheric concentration were measured directly in the air expelled with meltwater at a subglacial discharge point from the Greenland Ice Sheet. The range of hourly subglacial CH4 flux rate through the discharge point was estimated to be 3.1 to 134 g CH4 hr-1. These measurements are the first observations of direct emissions of CH4 from the subglacial environment under the Greenlandic Ice Sheet to the atmosphere and indicate a novel emission pathway of CH4 that is currently a non-quantified component of the Arctic CH4 budget.
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20
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Ma H, Yan W, Xiao X, Shi G, Li Y, Sun B, Dou Y, Zhang Y. Ex Situ Culturing Experiments Revealed Psychrophilic Hydrogentrophic Methanogenesis Being the Potential Dominant Methane-Producing Pathway in Subglacial Sediment in Larsemann Hills, Antarctic. Front Microbiol 2018. [PMID: 29515536 PMCID: PMC5826372 DOI: 10.3389/fmicb.2018.00237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
It was recognized only recently that subglacial ecosystems support considerable methanogenic activity, thus significantly contributing the global methane production. However, only limited knowledge is available on the physiological characteristics of this kind of methanogenic community because of the technical constraints associated with sampling and cultivation under corresponding environmental conditions. To elucidate methanogenesis beneath the glacial margin in East Antarctic Ice Sheet, we took an integrated approach that included cultivation of microbes associated with the sediment samples in the lab and analysis of mcrA gene therein. After 7 months of incubation, the highest rate of methanogenesis [398 (pmol/day)/gram] was observed at 1°C on a supply of H2. The rates of methanogenesis were lower on acetate or unamended substrate than on H2. The rates on these two substrates increased when the temperature was raised. Methanomicrobiales predominated before and after prolonged incubation, regardless whether H2, acetate, or unamended substrate were the energy source. Therefore, it was inferred that psychrophilic hydrogenotrophic methanogenesis was the primary methane-producing pathway in the subglacial ecosystem we sampled. These findings highlight the effects of temperature and substrate on potential methanogenesis in the subglacial sediment of this area, and may help us for a better estimation on the Antarctica methane production in a changing climate.
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Affiliation(s)
- Hongmei Ma
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Wenkai Yan
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Xiao
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Guitao Shi
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Yuansheng Li
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Bo Sun
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Yinke Dou
- College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Yu Zhang
- State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, China.,Institute of Oceanography, Shanghai Jiao Tong University, Shanghai, China
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21
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Amenabar MJ, Shock EL, Roden EE, Peters JW, Boyd ES. Microbial substrate preference dictated by energy demand, not supply. NATURE GEOSCIENCE 2017; 10:577-581. [PMID: 30944580 PMCID: PMC6443248 DOI: 10.1038/ngeo2978] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 06/02/2017] [Indexed: 06/08/2023]
Abstract
Growth substrates that maximize energy yield are widely thought to be utilized preferentially by microorganisms. However, observed distributions of microorganisms and their activities often deviate from predictions based solely on thermodynamic considerations of substrate energy supply. Here we present observations of the bioenergetics and growth yields of a metabolically flexible, thermophilic strain of the archaeon Acidianus when grown autotrophically on minimal medium with hydrogen (H2) or elemental sulfur (S°) as an electron donor, and S° or ferric iron (Fe3+) as an electron acceptor. Thermodynamic calculations indicate that S°/Fe3+ and H2/Fe3+ yield three- and four-fold more energy per mol electron transferred, respectively, than the H2/S° couple. However, biomass yields in Acidianus cultures provided with H2/S° were eight-fold greater than when provided S°/Fe3+ or H2/Fe3+, indicating the H2/S° redox couple is preferred. Indeed, cells provided with all three growth substrates (H2, Fe3+, and S°) grew preferentially by reduction of S° with H2. We conclude that substrate preference is dictated by differences in the energy demand of electron transfer reactions in Acidianus when grown with different substrates, rather than substrate energy supply.
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Affiliation(s)
| | - Everett L. Shock
- School of Earth & Space Exploration and School of Molecular Sciences, Arizona State University, Tempe, Arizona
- NASA Astrobiology Institute, Mountain View, California
| | - Eric E. Roden
- Department of Geosciences, University of Wisconsin, Madison, Wisconsin
- NASA Astrobiology Institute, Mountain View, California
| | - John W. Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana
| | - Eric S. Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana
- NASA Astrobiology Institute, Mountain View, California
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22
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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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23
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Cameron KA, Stibal M, Olsen NS, Mikkelsen AB, Elberling B, Jacobsen CS. Potential Activity of Subglacial Microbiota Transported to Anoxic River Delta Sediments. MICROBIAL ECOLOGY 2017; 74:6-9. [PMID: 28070677 PMCID: PMC5486838 DOI: 10.1007/s00248-016-0926-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/26/2016] [Indexed: 06/06/2023]
Abstract
The Watson River drains a portion of the SW Greenland ice sheet, transporting microbial communities from subglacial environments to a delta at the head of Søndre Strømfjord. This study investigates the potential activity and community shifts of glacial microbiota deposited and buried under layers of sediments within the river delta. A long-term (12-month) incubation experiment was established using Watson River delta sediment under anaerobic conditions, with and without CO2/H2 enrichment. Within CO2/H2-amended incubations, sulphate depletion and a shift in the microbial community to a 52% predominance of Desulfosporosinus meridiei by day 371 provides evidence for sulphate reduction. We found evidence of methanogenesis in CO2/H2-amended incubations within the first 5 months, with production rates of ~4 pmol g-1 d-1, which was likely performed by methanogenic Methanomicrobiales- and Methanosarcinales-related organisms. Later, a reduction in methane was observed to be paired with the depletion of sulphate, and we hypothesise that sulphate reduction out competed hydrogenotrophic methanogenesis. The structure and diversity of the original CO2/H2-amended incubation communities changed dramatically with a major shift in predominant community members and a decline in diversity and cell abundance. These results highlight the need for further investigations into the fate of subglacial microbiota within downstream environments.
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Affiliation(s)
- Karen A Cameron
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Penglais, Aberystwyth, SY23 3FL, UK.
| | - Marek Stibal
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 43, Prague, Czech Republic
| | - Nikoline S Olsen
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
| | - Andreas B Mikkelsen
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
| | - Bo Elberling
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
| | - Carsten S Jacobsen
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350, Copenhagen, Denmark
- Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark
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24
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Hotaling S, Hood E, Hamilton TL. Microbial ecology of mountain glacier ecosystems: biodiversity, ecological connections and implications of a warming climate. Environ Microbiol 2017; 19:2935-2948. [PMID: 28419666 DOI: 10.1111/1462-2920.13766] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/08/2017] [Accepted: 04/11/2017] [Indexed: 11/29/2022]
Abstract
Glacier ecosystems are teeming with life on, beneath, and to a lesser degree, within their icy masses. This conclusion largely stems from polar research, with less attention paid to mountain glaciers that overlap environmentally and ecologically with their polar counterparts in some ways, but diverge in others. One difference lies in the susceptibility of mountain glaciers to the near-term threat of climate change, as they tend to be much smaller in both area and volume. Moreover, mountain glaciers are typically steeper, more dependent upon basal sliding for movement, and experience higher seasonal precipitation. Here, we provide a modern synthesis of the microbial ecology of mountain glacier ecosystems, and particularly those at low- to mid-latitudes. We focus on five ecological zones: the supraglacial surface, englacial interior, subglacial bedrock-ice interface, proglacial streams and glacier forefields. For each, we discuss the role of microbiota in biogeochemical cycling and outline ecological and hydrological connections among zones, underscoring the interconnected nature of these ecosystems. Collectively, we highlight the need to: better document the biodiversity and functional roles of mountain glacier microbiota; describe the ecological implications of rapid glacial retreat under climate change and resolve the relative contributions of ecological zones to broader ecosystem function.
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Affiliation(s)
- Scott Hotaling
- Department of Biology, University of Kentucky, Lexington, KY, 40506, USA
| | - Eran Hood
- Department of Natural Science, University of Alaska Southeast, Juneau, AK, 99801, USA
| | - Trinity L Hamilton
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, 45221, USA
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25
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Diversity and abundance of microbial eukaryotes in stream sediments from Svalbard. Polar Biol 2017; 40:1835-1843. [PMID: 32009726 PMCID: PMC6961512 DOI: 10.1007/s00300-017-2106-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 10/25/2022]
Abstract
Microbial eukaryotes are increasingly being recognised for their role in global biogeochemical cycles, yet very few studies have focussed on their distribution in high-latitude stream sediments, an important habitat which influences stream water nutrient chemistry. In this study, we present the first comparison of microbial eukaryotes from two different polar habitats by determining the abundance and taxonomic affiliation of 18S rRNA gene fragments recovered from four sediment samples in Svalbard: two from a glaciated catchment and two from an unglaciated permafrost-dominated catchment. Whilst there was no difference between the two catchments in terms of Rao's phylogenetic diversity (0.18±0.04, 1SD), the glaciated catchment samples had slightly higher richness (138-139) than the unglaciated catchment samples (67-106). At the phylum level, Ciliophora had the highest relative abundance in the samples from the glaciated catchment (32-63%), but only comprised 0-17% of the unglaciated catchment samples. Bacillariophyta was the most abundant phylum in one of the samples from the unglaciated catchment (43%) but phototrophic microbial eukaryotes only formed a minor component of the glaciated catchment samples (<2%), suggesting that in these environments the microbial eukaryotes are predominantly heterotrophic (chemotrophic). This is in contrast to previously published data from Robertson Glacier, Canada where the relative abundance of chlorophyta (phototrophs) in three samples was 48-57%. The contrast may be due to differences in glacial hydrology and/or geology, highlighting the variation in microbial eukaryote communities between nominally similar environments.
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Welte CU, Rasigraf O, Vaksmaa A, Versantvoort W, Arshad A, Op den Camp HJM, Jetten MSM, Lüke C, Reimann J. Nitrate- and nitrite-dependent anaerobic oxidation of methane. ENVIRONMENTAL MICROBIOLOGY REPORTS 2016; 8:941-955. [PMID: 27753265 DOI: 10.1111/1758-2229.12487] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Microbial methane oxidation is an important process to reduce the emission of the greenhouse gas methane. Anaerobic microorganisms couple the oxidation of methane to the reduction of sulfate, nitrate and nitrite, and possibly oxidized iron and manganese minerals. In this article, we review the recent finding of the intriguing nitrate- and nitrite-dependent anaerobic oxidation of methane (AOM). Nitrate-dependent AOM is catalyzed by anaerobic archaea belonging to the ANME-2d clade closely related to Methanosarcina methanogens. They were named 'Candidatus Methanoperedens nitroreducens' and use reverse methanogenesis with the key enzyme methyl-coenzyme M (methyl-CoM) reductase for methane activation. Their major end product is nitrite which can be taken up by nitrite-dependent methanotrophs. Nitrite-dependent AOM is performed by the NC10 bacterium 'Candidatus Methylomirabilis oxyfera' that probably utilizes an intra-aerobic pathway through the dismutation of NO to N2 and O2 for aerobic methane activation by methane monooxygenase, yet being a strictly anaerobic microbe. Environmental distribution, physiological and biochemical aspects are discussed in this article as well as the cooperation of the microorganisms involved.
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Affiliation(s)
- Cornelia U Welte
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
- Soehngen Institute of Anaerobic Microbiology, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Olivia Rasigraf
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
- Netherlands Earth Systems Science Center, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Annika Vaksmaa
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Arslan Arshad
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
- Soehngen Institute of Anaerobic Microbiology, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
- Netherlands Earth Systems Science Center, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Claudia Lüke
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
| | - Joachim Reimann
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, Nijmegen, AJ, 6525, The Netherlands
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Achberger AM, Christner BC, Michaud AB, Priscu JC, Skidmore ML, Vick-Majors TJ. Microbial Community Structure of Subglacial Lake Whillans, West Antarctica. Front Microbiol 2016; 7:1457. [PMID: 27713727 PMCID: PMC5032586 DOI: 10.3389/fmicb.2016.01457] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/31/2016] [Indexed: 11/13/2022] Open
Abstract
Subglacial Lake Whillans (SLW) is located beneath ∼800 m of ice on the Whillans Ice Stream in West Antarctica and was sampled in January of 2013, providing the first opportunity to directly examine water and sediments from an Antarctic subglacial lake. To minimize the introduction of surface contaminants to SLW during its exploration, an access borehole was created using a microbiologically clean hot water drill designed to reduce the number and viability of microorganisms in the drilling water. Analysis of 16S rRNA genes (rDNA) amplified from samples of the drilling and borehole water allowed an evaluation of the efficacy of this approach and enabled a confident assessment of the SLW ecosystem inhabitants. Based on an analysis of 16S rDNA and rRNA (i.e., reverse-transcribed rRNA molecules) data, the SLW community was found to be bacterially dominated and compositionally distinct from the assemblages identified in the drill system. The abundance of bacteria (e.g., Candidatus Nitrotoga, Sideroxydans, Thiobacillus, and Albidiferax) and archaea (Candidatus Nitrosoarchaeum) related to chemolithoautotrophs was consistent with the oxidation of reduced iron, sulfur, and nitrogen compounds having important roles as pathways for primary production in this permanently dark ecosystem. Further, the prevalence of Methylobacter in surficial lake sediments combined with the detection of methanogenic taxa in the deepest sediment horizons analyzed (34–36 cm) supported the hypothesis that methane cycling occurs beneath the West Antarctic Ice Sheet. Large ratios of rRNA to rDNA were observed for several operational taxonomic units abundant in the water column and sediments (e.g., Albidiferax, Methylobacter, Candidatus Nitrotoga, Sideroxydans, and Smithella), suggesting a potentially active role for these taxa in the SLW ecosystem. Our findings are consistent with chemosynthetic microorganisms serving as the ecological foundation in this dark subsurface environment, providing new organic matter that sustains a microbial ecosystem beneath the West Antarctic Ice Sheet.
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Affiliation(s)
- Amanda M Achberger
- Department of Biological Sciences, Louisiana State University, Baton Rouge LA, USA
| | - Brent C Christner
- Department of Biological Sciences, Louisiana State University, Baton RougeLA, USA; Department of Microbiology and Cell Science, University of Florida, GainesvilleFL, USA; Biodiversity Institute, University of Florida, GainesvilleFL, USA
| | - Alexander B Michaud
- Department of Land Resources and Environmental Science, Montana State University, Bozeman MT, USA
| | - John C Priscu
- Department of Land Resources and Environmental Science, Montana State University, Bozeman MT, USA
| | - Mark L Skidmore
- Department of Earth Sciences, Montana State University, Bozeman MT, USA
| | - Trista J Vick-Majors
- Department of Land Resources and Environmental Science, Montana State University, Bozeman MT, USA
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Hofmann K, Pauli H, Praeg N, Wagner AO, Illmer P. Methane-cycling microorganisms in soils of a high-alpine altitudinal gradient. FEMS Microbiol Ecol 2016; 92:fiw009. [PMID: 26790465 DOI: 10.1093/femsec/fiw009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2016] [Indexed: 11/13/2022] Open
Abstract
Methanogens and methanotrophs play unique roles as producers and consumers of the greenhouse gas methane (CH4) in soils, respectively. Here, we aimed to reveal whether and to which extent methane-cyclers occur in high-alpine soils, and to assess their spatial distribution along an altitudinal gradient (2700-3500 m) in the Austrian Alps at sites located within the alpine (2700-2900 m), the alpine-nival (3000-3100 m) and the nival belts (3200-3500 m). Methanococcales and Methanocella spp. were most abundant among all quantified methanogenic guilds, whereas Methanosarcinales were not detected in the studied soil. The detected methanogens seem to be capable of persisting despite a highly oxic low-temperature environment. Methanogenic and methanotrophic activities and abundances of methanotrophs, Methanococcales and Methanocella spp. declined with altitude. Methanogenic and methanotrophic abundances were best explained by mean annual soil temperature and dissolved organic carbon, respectively. Alpine belt soils harbored significantly more methane-cyclers than those of the nival belt, indicating some influence of plant cover. Our results show that methanogens are capable of persisting in high-alpine cold soils and might help to understand future changes of these environments caused by climate warming.
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Affiliation(s)
- Katrin Hofmann
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Harald Pauli
- Institute for Interdisciplinary Mountain Research, Austrian Academy of Sciences and Center for Global Change and Sustainability, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Nadine Praeg
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Andreas O Wagner
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Paul Illmer
- Institute of Microbiology, University of Innsbruck, 6020 Innsbruck, Austria
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Aerobic and Anaerobic Thiosulfate Oxidation by a Cold-Adapted, Subglacial Chemoautotroph. Appl Environ Microbiol 2015; 82:1486-95. [PMID: 26712544 DOI: 10.1128/aem.03398-15] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 12/15/2015] [Indexed: 11/20/2022] Open
Abstract
Geochemical data indicate that protons released during pyrite (FeS2) oxidation are important drivers of mineral weathering in oxic and anoxic zones of many aquatic environments, including those beneath glaciers. Oxidation of FeS2 under oxic, circumneutral conditions proceeds through the metastable intermediate thiosulfate (S2O3 (2-)), which represents an electron donor capable of supporting microbial metabolism. Subglacial meltwaters sampled from Robertson Glacier (RG), Canada, over a seasonal melt cycle revealed concentrations of S2O3 (2-) that were typically below the limit of detection, despite the presence of available pyrite and concentrations of the FeS2 oxidation product sulfate (SO4 (2-)) several orders of magnitude higher than those of S2O3 (2-). Here we report on the physiological and genomic characterization of the chemolithoautotrophic facultative anaerobe Thiobacillus sp. strain RG5 isolated from the subglacial environment at RG. The RG5 genome encodes genes involved with pathways for the complete oxidation of S2O3 (2-), CO2 fixation, and aerobic and anaerobic respiration with nitrite or nitrate. Growth experiments indicated that the energy required to synthesize a cell under oxygen- or nitrate-reducing conditions with S2O3 (2-) as the electron donor was lower at 5.1°C than 14.4°C, indicating that this organism is cold adapted. RG sediment-associated transcripts of soxB, which encodes a component of the S2O3 (2-)-oxidizing complex, were closely affiliated with soxB from RG5. Collectively, these results suggest an active sulfur cycle in the subglacial environment at RG mediated in part by populations closely affiliated with RG5. The consumption of S2O3 (2-) by RG5-like populations may accelerate abiotic FeS2 oxidation, thereby enhancing mineral weathering in the subglacial environment.
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Boetius A, Anesio AM, Deming JW, Mikucki JA, Rapp JZ. Microbial ecology of the cryosphere: sea ice and glacial habitats. Nat Rev Microbiol 2015; 13:677-90. [PMID: 26344407 DOI: 10.1038/nrmicro3522] [Citation(s) in RCA: 206] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Earth's cryosphere comprises those regions that are cold enough for water to turn into ice. Recent findings show that the icy realms of polar oceans, glaciers and ice sheets are inhabited by microorganisms of all three domains of life, and that temperatures below 0 °C are an integral force in the diversification of microbial life. Cold-adapted microorganisms maintain key ecological functions in icy habitats: where sunlight penetrates the ice, photoautotrophy is the basis for complex food webs, whereas in dark subglacial habitats, chemoautotrophy reigns. This Review summarizes current knowledge of the microbial ecology of frozen waters, including the diversity of niches, the composition of microbial communities at these sites and their biogeochemical activities.
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Affiliation(s)
- Antje Boetius
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.,Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany
| | - Alexandre M Anesio
- Bristol Glaciology Center, School of Geographical Sciences, University of Bristol, BS8 1SS, UK
| | - Jody W Deming
- School of Oceanography, Box 357940, University of Washington, Seattle, Washington 98195, USA
| | - Jill A Mikucki
- Department of Biology, 276 Bicentennial Way, Middlebury College, Middlebury, Vermont 05753, USA
| | - Josephine Z Rapp
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany.,Max Planck Institute for Marine Microbiology, Celsiusstraße 1, 28359 Bremen, Germany
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Sheik CS, Stevenson EI, Den Uyl PA, Arendt CA, Aciego SM, Dick GJ. Microbial communities of the Lemon Creek Glacier show subtle structural variation yet stable phylogenetic composition over space and time. Front Microbiol 2015; 6:495. [PMID: 26042114 PMCID: PMC4438255 DOI: 10.3389/fmicb.2015.00495] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 05/05/2015] [Indexed: 11/13/2022] Open
Abstract
Glaciers are geologically important yet transient ecosystems that support diverse, biogeochemically significant microbial communities. During the melt season glaciers undergo dramatic physical, geochemical, and biological changes that exert great influence on downstream biogeochemical cycles. Thus, we sought to understand the temporal melt-season dynamics of microbial communities and associated geochemistry at the terminus of Lemon Creek Glacier (LCG) in coastal southern Alaska. Due to late season snowfall, sampling of LCG occurred in three interconnected areas: proglacial Lake Thomas, the lower glacial outflow stream, and the glacier’s terminus. LCG associated microbial communities were phylogenetically diverse and varied by sampling location. However, Betaproteobacteria, Alphaproteobacteria, and Bacteroidetes dominated communities at all sampling locations. Strict anaerobic groups such as methanogens, SR1, and OP11 were also recovered from glacier outflows, indicating anoxic conditions in at least some portions of the LCG subglacial environment. Microbial community structure was significantly correlated with sampling location and sodium concentrations. Microbial communities sampled from terminus outflow waters exhibited day-to-day fluctuation in taxonomy and phylogenetic similarity. However, these communities were not significantly different from randomly constructed communities from all three sites. These results indicate that glacial outflows share a large proportion of phylogenetic overlap with downstream environments and that the observed significant shifts in community structure are driven by changes in relative abundance of different taxa, and not complete restructuring of communities. We conclude that LCG glacial discharge hosts a diverse and relatively stable microbiome that shifts at fine taxonomic scales in response to geochemistry and likely water residence time.
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Affiliation(s)
- Cody S Sheik
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA ; Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI USA
| | - Emily I Stevenson
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA
| | - Paul A Den Uyl
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA
| | - Carli A Arendt
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA
| | - Sarah M Aciego
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA
| | - Gregory J Dick
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI USA ; Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI USA ; Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI USA
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Dieser M, Broemsen ELJE, Cameron KA, King GM, Achberger A, Choquette K, Hagedorn B, Sletten R, Junge K, Christner BC. Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland Ice Sheet. THE ISME JOURNAL 2014; 8:2305-16. [PMID: 24739624 PMCID: PMC4992074 DOI: 10.1038/ismej.2014.59] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 03/08/2014] [Accepted: 03/14/2014] [Indexed: 11/08/2022]
Abstract
Microbial processes that mineralize organic carbon and enhance solute production at the bed of polar ice sheets could be of a magnitude sufficient to affect global elemental cycles. To investigate the biogeochemistry of a polar subglacial microbial ecosystem, we analyzed water discharged during the summer of 2012 and 2013 from Russell Glacier, a land-terminating outlet glacier at the western margin of the Greenland Ice Sheet. The molecular data implied that the most abundant and active component of the subglacial microbial community at these marginal locations were bacteria within the order Methylococcales (59-100% of reverse transcribed (RT)-rRNA sequences). mRNA transcripts of the particulate methane monooxygenase (pmoA) from these taxa were also detected, confirming that methanotrophic bacteria were functional members of this subglacial ecosystem. Dissolved methane ranged between 2.7 and 83 μM in the subglacial waters analyzed, and the concentration was inversely correlated with dissolved oxygen while positively correlated with electrical conductivity. Subglacial microbial methane production was supported by δ(13)C-CH4 values between -64‰ and -62‰ together with the recovery of RT-rRNA sequences that classified within the Methanosarcinales and Methanomicrobiales. Under aerobic conditions, >98% of the methane in the subglacial water was consumed over ∼30 days incubation at ∼4 °C and rates of methane oxidation were estimated at 0.32 μM per day. Our results support the occurrence of active methane cycling beneath this region of the Greenland Ice Sheet, where microbial communities poised in oxygenated subglacial drainage channels could serve as significant methane sinks.
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Affiliation(s)
- Markus Dieser
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Erik L J E Broemsen
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Karen A Cameron
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, WA, USA
| | - Gary M King
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Amanda Achberger
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Kyla Choquette
- Applied Science Engineering and Technology Laboratory, Environment and Natural Resources Institute, University of Alaska Anchorage, Anchorage, AK, USA
| | - Birgit Hagedorn
- Applied Science Engineering and Technology Laboratory, Environment and Natural Resources Institute, University of Alaska Anchorage, Anchorage, AK, USA
| | - Ron Sletten
- Department of Earth and Space Sciences, University of Washington, Seattle, WA, USA
| | - Karen Junge
- Applied Physics Laboratory, Polar Science Center, University of Washington, Seattle, WA, USA
| | - Brent C Christner
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
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Karaevskaya ES, Demchenko LS, Demidov NE, Rivkina EM, Bulat SA, Gilichinsky DA. Archaeal diversity in permafrost deposits of Bunger Hills Oasis and King George Island (Antarctica) according to the 16S rRNA gene sequencing. Microbiology (Reading) 2014. [DOI: 10.1134/s0026261714040092] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Abstract
Glacial comminution of bedrock generates fresh mineral surfaces capable of sustaining chemotrophic microbial communities under the dark conditions that pervade subglacial habitats. Geochemical and isotopic evidence suggests that pyrite oxidation is a dominant weathering process generating protons that drive mineral dissolution in many subglacial systems. Here, we provide evidence correlating pyrite oxidation with chemosynthetic primary productivity and carbonate dissolution in subglacial sediments sampled from Robertson Glacier (RG), Alberta, Canada. Quantification and sequencing of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) transcripts suggest that populations closely affiliated with Sideroxydans lithotrophicus, an iron sulfide-oxidizing autotrophic bacterium, are abundant constituents of microbial communities at RG. Microcosm experiments indicate sulfate production during biological assimilation of radiolabeled bicarbonate. Geochemical analyses of subglacial meltwater indicate that increases in sulfate levels are associated with increased calcite and dolomite dissolution. Collectively, these data suggest a role for biological pyrite oxidation in driving primary productivity and mineral dissolution in a subglacial environment and provide the first rate estimate for bicarbonate assimilation in these ecosystems. Evidence for lithotrophic primary production in this contemporary subglacial environment provides a plausible mechanism to explain how subglacial communities could be sustained in near-isolation from the atmosphere during glacial-interglacial cycles.
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Meuser JE, Baxter BK, Spear JR, Peters JW, Posewitz MC, Boyd ES. Contrasting patterns of community assembly in the stratified water column of Great Salt Lake, Utah. MICROBIAL ECOLOGY 2013; 66:268-80. [PMID: 23354179 DOI: 10.1007/s00248-013-0180-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 01/09/2013] [Indexed: 05/26/2023]
Abstract
Phylogenetic examinations of communities sampled along geochemical gradients provide a framework for inferring the relative importance of niche-based ecological interactions (competition, environmental filtering) and neutral-based evolutionary interactions in structuring biodiversity. Great Salt Lake (GSL) in Utah exhibits strong spatial gradients due to both seasonal variation in freshwater input into the watershed and restricted fluid flow within North America's largest saline terminal lake ecosystem. Here, we examine the phylogenetic structure and composition of archaeal, bacterial, and eukaryal small subunit (SSU) rRNA genes sampled along a stratified water column (DWR3) in the south arm of GSL in order to infer the underlying mechanism of community assembly. Communities sampled from the DWR3 epilimnion were phylogenetically clustered (i.e., coexistence of close relatives due to environmental filtering) whereas those sampled from the DWR3 hypolimnion were phylogenetically overdispersed (i.e., coexistence of distant relatives due to competitive interactions), with minimal evidence for a role for neutral processes in structuring any assemblage. The shift from phylogenetically clustered to overdispersed assemblages was associated with an increase in salinity and a decrease in dissolved O2 (DO) concentration. Likewise, the phylogenetic diversity and phylogenetic similarity of assemblages was strongly associated with salinity or DO gradients. Thus, salinity and/or DO appeared to influence the mechanism of community assembly as well as the phylogenetic diversity and composition of communities. It is proposed that the observed patterns in the phylogenetic composition and structure of DWR3 assemblages are attributable to the meromictic nature of GSL, which prevents significant mixing between the epilimnion and the hypolimnion. This leads to strong physicochemical gradients at the halocline, which are capable of supporting a greater diversity. However, concomitant shifts in nutrient availability (e.g., DO) at and below the halocline drive competitive interactions leading to hypolimnion assemblages with minimal niche overlap.
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Affiliation(s)
- Jonathan E Meuser
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
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Hamilton TL, Peters JW, Skidmore ML, Boyd ES. Molecular evidence for an active endogenous microbiome beneath glacial ice. ISME JOURNAL 2013; 7:1402-12. [PMID: 23486249 PMCID: PMC3695297 DOI: 10.1038/ismej.2013.31] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Geologic, chemical and isotopic evidence indicate that Earth has experienced numerous intervals of widespread glaciation throughout its history, with roughly 11% of present day Earth's land surface covered in ice. Despite the pervasive nature of glacial ice both today and in Earth's past and the potential contribution of these systems to global biogeochemical cycles, the composition and phylogenetic structure of an active microbial community in subglacial systems has yet to be described. Here, using RNA-based approaches, we demonstrate the presence of active and endogenous archaeal, bacterial and eukaryal assemblages in cold (0–1 °C) subglacial sediments sampled from Robertson Glacier, Alberta, Canada. Patterns in the phylogenetic structure and composition of subglacial sediment small subunit (SSU) ribosomal RNA (rRNA) assemblages indicate greater diversity and evenness than in glacial surface environments, possibly due to facilitative or competitive interactions among populations in the subglacial environment. The combination of phylogenetically more even and more diverse assemblages in the subglacial environment suggests minimal niche overlap and optimization to capture a wider spectrum of the limited nutrients and chemical energy made available from weathering of bedrock minerals. The prevalence of SSU rRNA affiliated with lithoautotrophic bacteria, autotrophic methane producing archaea and heterotrophic eukarya in the subglacial environment is consistent with this hypothesis and suggests an active contribution to the global carbon cycle. Collectively, our findings demonstrate that subglacial environments harbor endogenous active ecosystems that have the potential to impact global biogeochemical cycles over extended periods of time.
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Affiliation(s)
- Trinity L Hamilton
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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37
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Potential methane reservoirs beneath Antarctica. Nature 2012; 488:633-7. [PMID: 22932387 DOI: 10.1038/nature11374] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 06/28/2012] [Indexed: 11/09/2022]
Abstract
Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14 kilometres thick and an estimated 21,000 petagrams (1 Pg equals 10(15) g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300 metres in West Antarctica and 700 metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage.
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Irvine-Fynn TDL, Edwards A, Newton S, Langford H, Rassner SM, Telling J, Anesio AM, Hodson AJ. Microbial cell budgets of an Arctic glacier surface quantified using flow cytometry. Environ Microbiol 2012; 14:2998-3012. [PMID: 23016868 DOI: 10.1111/j.1462-2920.2012.02876.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/16/2012] [Accepted: 08/17/2012] [Indexed: 11/28/2022]
Abstract
Uncertainty surrounds estimates of microbial cell and organic detritus fluxes from glacier surfaces. Here, we present the first enumeration of biological particles draining from a supraglacial catchment, on Midtre Lovénbreen (Svalbard) over 36 days. A stream cell flux of 1.08 × 10(7) cells m(-2) h(-1) was found, with strong inverse, non-linear associations between water discharge and biological particle concentrations. Over the study period, a significant decrease in cell-like particles exhibiting 530 nm autofluorescence was noted. The observed total fluvial export of ~7.5 × 10(14) cells equates to 15.1-72.7 g C, and a large proportion of these cells were small (< 0.5 μm in diameter). Differences between the observed fluvial export and inputs from ice-melt and aeolian deposition were marked: results indicate an apparent storage rate of 8.83 × 10(7) cells m(-2) h(-1). Analysis of surface ice cores revealed cell concentrations comparable to previous studies (6 × 10(4) cells ml(-1)) but, critically, showed no variation with depth in the uppermost 1 m. The physical retention and growth of particulates at glacier surfaces has two implications: to contribute to ice mass thinning through feedbacks altering surface albedo, and to potentially seed recently deglaciated terrain with cells, genes and labile organic matter. This highlights the merit of further study into glacier surface hydraulics and biological processes.
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Affiliation(s)
- T D L Irvine-Fynn
- Institute of Geography and Earth Science, Aberystwyth University, Aberystwyth, SY23 3DB, UK.
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Marteinsson VT, Rúnarsson Á, Stefánsson A, Thorsteinsson T, Jóhannesson T, Magnússon SH, Reynisson E, Einarsson B, Wade N, Morrison HG, Gaidos E. Microbial communities in the subglacial waters of the Vatnajökull ice cap, Iceland. ISME JOURNAL 2012; 7:427-37. [PMID: 22975882 DOI: 10.1038/ismej.2012.97] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Subglacial lakes beneath the Vatnajökull ice cap in Iceland host endemic communities of microorganisms adapted to cold, dark and nutrient-poor waters, but the mechanisms by which these microbes disseminate under the ice and colonize these lakes are unknown. We present new data on this subglacial microbiome generated from samples of two subglacial lakes, a subglacial flood and a lake that was formerly subglacial but now partly exposed to the atmosphere. These data include parallel 16S rRNA gene amplicon libraries constructed using novel primers that span the v3-v5 and v4-v6 hypervariable regions. Archaea were not detected in either subglacial lake, and the communities are dominated by only five bacterial taxa. Our paired libraries are highly concordant for the most abundant taxa, but estimates of diversity (abundance-based coverage estimator) in the v4-v6 libraries are 3-8 times higher than in corresponding v3-v5 libraries. The dominant taxa are closely related to cultivated anaerobes and microaerobes, and may occupy unique metabolic niches in a chemoautolithotrophic ecosystem. The populations of the major taxa in the subglacial lakes are indistinguishable (>99% sequence identity), despite separation by 6 km and an ice divide; one taxon is ubiquitous in our Vatnajökull samples. We propose that the glacial bed is connected through an aquifer in the underlying permeable basalt, and these subglacial lakes are colonized from a deeper, subterranean microbiome.
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Dissolved gases in frozen basal water from the NGRIP borehole: implications for biogeochemical processes beneath the Greenland Ice Sheet. Polar Biol 2012. [DOI: 10.1007/s00300-012-1198-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Stibal M, Hasan F, Wadham JL, Sharp MJ, Anesio AM. Prokaryotic diversity in sediments beneath two polar glaciers with contrasting organic carbon substrates. Extremophiles 2012; 16:255-65. [PMID: 22241643 DOI: 10.1007/s00792-011-0426-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 12/13/2011] [Indexed: 01/12/2023]
Abstract
Microbial ecosystems beneath glaciers and ice sheets are thought to play an active role in regional and global carbon cycling. Subglacial sediments are assumed to be largely anoxic, and thus various pathways of organic carbon metabolism may occur here. We examine the abundance and diversity of prokaryotes in sediment beneath two glaciers (Lower Wright Glacier in Antarctica and Russell Glacier in Greenland) with different glaciation histories and thus with different organic carbon substrates. The total microbial abundance in the Lower Wright Glacier sediment, originating from young lacustrine sediment, was an order of magnitude higher (~8 × 10(6) cells per gram of wet sediment) than in Russell Glacier sediment (~9 × 10(5) cells g(-1)) that is of Holocene-aged soil origin. 4% of the microbes from the Russell Glacier sediment and 0.04-0.35% from Lower Wright Glacier were culturable at 10°C. The Lower Wright Glacier subglacial community was dominated by Proteobacteria, followed by Firmicutes. The Russell Glacier library was much less diverse and also dominated by Proteobacteria. Low numbers and diversity of both Euryarchaeota and Crenarchaeota were found in both sediments. The identified clones were related to bacteria with both aerobic and anaerobic metabolisms, indicating the presence of both oxic and anoxic conditions in the sediments.
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Affiliation(s)
- Marek Stibal
- Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, BS8 1SS, UK.
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Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem. Appl Environ Microbiol 2011; 77:4778-87. [PMID: 21622799 DOI: 10.1128/aem.00376-11] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated at 4°C were 280 and 18.5 nmol of N per g of dry weight sediment per day, respectively, indicating the potential for these processes to occur in situ. Geochemical analyses of subglacial sediment pore waters and bulk subglacial meltwaters revealed low concentrations of inorganic and organic nitrogen compounds. These data, when coupled with a C/N atomic ratio of dissolved organic matter in subglacial pore waters of ~210, indicate that the sediment communities are N limited. This may reflect the combined biological activities of organic N mineralization, nitrification, and nitrate reduction. Despite evidence of N limitation and the detection of nifH, we were unable to detect biological nitrogen fixation activity in subglacial sediments. Collectively, the results presented here suggest a role for nitrification and nitrate reduction in sustaining microbial life in subglacial environments. Considering that ice currently covers 11% of the terrestrial landmass and has covered significantly greater portions of Earth at times in the past, the demonstration of nitrification and nitrate reduction in subglacial environments furthers our understanding of the potential for these environments to contribute to global biogeochemical cycles on glacial-interglacial timescales.
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Skidmore M. Microbial communities in Antarctic subglacial aquatic environments. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010gm000995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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