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Wen Q, Yin X, Moming A, Liu G, Jiang B, Wang J, Fan Z, Sajjad W, Ge Y, Kang S, Shen S, Deng F. Viral communities locked in high elevation permafrost up to 100 m in depth on the Tibetan Plateau. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 932:172829. [PMID: 38692332 DOI: 10.1016/j.scitotenv.2024.172829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/02/2024] [Accepted: 04/25/2024] [Indexed: 05/03/2024]
Abstract
Permafrost serves as a natural cold reservoir for viral communities. However, little is known about the viromes in deep permafrost soil, as most studies of permafrost were restricted to shallow areas. Here, permafrost soil samples of up to 100 m in depth were collected from two sites in the Tuotuo River permafrost area on the Tibetan Plateau. We investigated the viral composition in these permafrost soil samples and analyzed the relationship of viral composition and diversity along with depths. Our study revealed that greater permafrost thickness corresponds to higher diversity within the viral community. Bacteriophages were found to be the dominant viral communities, with "kill the winner" dynamics observed within the Siphoviridae and Myoviridae. The abundance and diversity of viral communities may follow a potential pattern along soil layers and depths, influenced by pH, trace elements, and permafrost thickness. Notably, strong correlations were discovered between the content of inorganic elements, including B, Mg, Cr, Bi, Ti, Na, Ni, and Cu, and the viral composition. Moreover, we discovered highly conserved sequences of giant viruses at depth of 10, 20, and 50 m in permafrost, which play a crucial role in evolutionary processes. These findings provide valuable insights into the viral community patterns from shallow to 100-m-depth in high-elevation permafrost, offering crucial data support for the formulation of strategies for permafrost thaw caused by climate change and anthropogenic activities.
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Affiliation(s)
- Qian Wen
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China; University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xiufeng Yin
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 730000 Lanzhou, China
| | - Abulimiti Moming
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China
| | - Guanyue Liu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 730000 Lanzhou, China
| | - Boyong Jiang
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China
| | - Jun Wang
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China
| | - Zhaojun Fan
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China
| | - Wasim Sajjad
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 730000 Lanzhou, China
| | - Yingying Ge
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China
| | - Shichang Kang
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, 730000 Lanzhou, China; University of Chinese Academy of Sciences, 100049 Beijing, China.
| | - Shu Shen
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China; Hubei Jiangxia Laboratory, 430200 Wuhan, China.
| | - Fei Deng
- Key Laboratory of Virology and Biosafety and National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, 430071 Wuhan, China.
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Shatilovich A, Gade VR, Pippel M, Hoffmeyer TT, Tchesunov AV, Stevens L, Winkler S, Hughes GM, Traikov S, Hiller M, Rivkina E, Schiffer PH, Myers EW, Kurzchalia TV. A novel nematode species from the Siberian permafrost shares adaptive mechanisms for cryptobiotic survival with C. elegans dauer larva. PLoS Genet 2023; 19:e1010798. [PMID: 37498820 PMCID: PMC10374039 DOI: 10.1371/journal.pgen.1010798] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 05/24/2023] [Indexed: 07/29/2023] Open
Abstract
Some organisms in nature have developed the ability to enter a state of suspended metabolism called cryptobiosis when environmental conditions are unfavorable. This state-transition requires execution of a combination of genetic and biochemical pathways that enable the organism to survive for prolonged periods. Recently, nematode individuals have been reanimated from Siberian permafrost after remaining in cryptobiosis. Preliminary analysis indicates that these nematodes belong to the genera Panagrolaimus and Plectus. Here, we present precise radiocarbon dating indicating that the Panagrolaimus individuals have remained in cryptobiosis since the late Pleistocene (~46,000 years). Phylogenetic inference based on our genome assembly and a detailed morphological analysis demonstrate that they belong to an undescribed species, which we named Panagrolaimus kolymaensis. Comparative genome analysis revealed that the molecular toolkit for cryptobiosis in P. kolymaensis and in C. elegans is partly orthologous. We show that biochemical mechanisms employed by these two species to survive desiccation and freezing under laboratory conditions are similar. Our experimental evidence also reveals that C. elegans dauer larvae can remain viable for longer periods in suspended animation than previously reported. Altogether, our findings demonstrate that nematodes evolved mechanisms potentially allowing them to suspend life over geological time scales.
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Affiliation(s)
- Anastasia Shatilovich
- Institute of Physicochemical and Biological Problems in Soil Science RAS, Pushchino, Russia
- Zoological Institute RAS, St. Petersburg, Russia
| | - Vamshidhar R. Gade
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | | | | | - Alexei V. Tchesunov
- Department of Invertebrate Zoology, Lomonosov Moscow State University, Moscow, Russia
| | - Lewis Stevens
- Tree of Life, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Sylke Winkler
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
- DRESDEN concept Genome Center, Dresden, Germany
| | - Graham M. Hughes
- School of Biology and Environmental Science, University College Dublin, Belfield, Dublin, Ireland
| | - Sofia Traikov
- Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Michael Hiller
- Center for Systems Biology, Dresden, Germany
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Society for Nature Research & Goethe University, Frankfurt am Main, Germany
| | - Elizaveta Rivkina
- Institute of Physicochemical and Biological Problems in Soil Science RAS, Pushchino, Russia
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Waldrop MP, Chabot CL, Liebner S, Holm S, Snyder MW, Dillon M, Dudgeon SR, Douglas TA, Leewis MC, Walter Anthony KM, McFarland JW, Arp CD, Bondurant AC, Taş N, Mackelprang R. Permafrost microbial communities and functional genes are structured by latitudinal and soil geochemical gradients. THE ISME JOURNAL 2023:10.1038/s41396-023-01429-6. [PMID: 37217592 DOI: 10.1038/s41396-023-01429-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 04/27/2023] [Accepted: 05/02/2023] [Indexed: 05/24/2023]
Abstract
Permafrost underlies approximately one quarter of Northern Hemisphere terrestrial surfaces and contains 25-50% of the global soil carbon (C) pool. Permafrost soils and the C stocks within are vulnerable to ongoing and future projected climate warming. The biogeography of microbial communities inhabiting permafrost has not been examined beyond a small number of sites focused on local-scale variation. Permafrost is different from other soils. Perennially frozen conditions in permafrost dictate that microbial communities do not turn over quickly, thus possibly providing strong linkages to past environments. Thus, the factors structuring the composition and function of microbial communities may differ from patterns observed in other terrestrial environments. Here, we analyzed 133 permafrost metagenomes from North America, Europe, and Asia. Permafrost biodiversity and taxonomic distribution varied in relation to pH, latitude and soil depth. The distribution of genes differed by latitude, soil depth, age, and pH. Genes that were the most highly variable across all sites were associated with energy metabolism and C-assimilation. Specifically, methanogenesis, fermentation, nitrate reduction, and replenishment of citric acid cycle intermediates. This suggests that adaptations to energy acquisition and substrate availability are among some of the strongest selective pressures shaping permafrost microbial communities. The spatial variation in metabolic potential has primed communities for specific biogeochemical processes as soils thaw due to climate change, which could cause regional- to global- scale variation in C and nitrogen processing and greenhouse gas emissions.
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Affiliation(s)
- Mark P Waldrop
- Geology, Minerals, Energy, and Geophysics Science Center, United States Geological Survey, Menlo Park, CA, 94025, USA.
| | - Christopher L Chabot
- California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
| | - Susanne Liebner
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, 14473, Potsdam, Germany
- University of Potsdam, Institute of Biochemistry and Biology, 14476, Potsdam, Germany
| | - Stine Holm
- GFZ German Research Centre for Geosciences, Section Geomicrobiology, 14473, Potsdam, Germany
| | - Michael W Snyder
- California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
| | - Megan Dillon
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Steven R Dudgeon
- California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA
| | - Thomas A Douglas
- U.S. Army Cold Regions Research and Engineering Laboratory 9th Avenue, Building 4070 Fort, Wainwright, AK, 99703, USA
| | - Mary-Cathrine Leewis
- Agriculture and Agri-Food Canada, 2560 Boulevard Hochelaga, Québec, QC, G1V 2J3, Canada
| | - Katey M Walter Anthony
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Jack W McFarland
- Geology, Minerals, Energy, and Geophysics Science Center, United States Geological Survey, Menlo Park, CA, 94025, USA
| | - Christopher D Arp
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Allen C Bondurant
- Water and Environmental Research Center, University Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Neslihan Taş
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Rachel Mackelprang
- California State University Northridge, 18111 Nordhoff St., Northridge, CA, 91330, USA.
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Wu X, Almatari AL, Cyr WA, Williams DE, Pfiffner SM, Rivkina EM, Lloyd KG, Vishnivetskaya TA. Microbial life in 25-m-deep boreholes in ancient permafrost illuminated by metagenomics. ENVIRONMENTAL MICROBIOME 2023; 18:33. [PMID: 37055869 PMCID: PMC10103415 DOI: 10.1186/s40793-023-00487-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 03/24/2023] [Indexed: 06/19/2023]
Abstract
This study describes the composition and potential metabolic adaptation of microbial communities in northeastern Siberia, a repository of the oldest permafrost in the Northern Hemisphere. Samples of contrasting depth (1.75 to 25.1 m below surface), age (from ~ 10 kyr to 1.1 Myr) and salinity (from low 0.1-0.2 ppt and brackish 0.3-1.3 ppt to saline 6.1 ppt) were collected from freshwater permafrost (FP) of borehole AL1_15 on the Alazeya River, and coastal brackish permafrost (BP) overlying marine permafrost (MP) of borehole CH1_17 on the East Siberian Sea coast. To avoid the limited view provided with culturing work, we used 16S rRNA gene sequencing to show that the biodiversity decreased dramatically with permafrost age. Nonmetric multidimensional scaling (NMDS) analysis placed the samples into three groups: FP and BP together (10-100 kyr old), MP (105-120 kyr old), and FP (> 900 kyr old). Younger FP/BP deposits were distinguished by the presence of Acidobacteriota, Bacteroidota, Chloroflexota_A, and Gemmatimonadota, older FP deposits had a higher proportion of Gammaproteobacteria, and older MP deposits had much more uncultured groups within Asgardarchaeota, Crenarchaeota, Chloroflexota, Patescibacteria, and unassigned archaea. The 60 recovered metagenome-assembled genomes and un-binned metagenomic assemblies suggested that despite the large taxonomic differences between samples, they all had a wide range of taxa capable of fermentation coupled to nitrate utilization, with the exception of sulfur reduction present only in old MP deposits.
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Affiliation(s)
- Xiaofen Wu
- Center for Environmental Biotechnology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996-1605, USA
| | - Abraham L Almatari
- Center for Environmental Biotechnology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996-1605, USA
| | - Wyatt A Cyr
- Center for Environmental Biotechnology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996-1605, USA
| | - Daniel E Williams
- Center for Environmental Biotechnology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996-1605, USA
| | - Susan M Pfiffner
- Center for Environmental Biotechnology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996-1605, USA
| | - Elizaveta M Rivkina
- Soil Cryology Laboratory, Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, Russia, 142290
| | - Karen G Lloyd
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Tatiana A Vishnivetskaya
- Center for Environmental Biotechnology, University of Tennessee, 1416 Circle Drive, Knoxville, TN, 37996-1605, USA.
- Soil Cryology Laboratory, Institute of Physicochemical and Biological Problems in Soil Science, Russian Academy of Sciences, Pushchino, Russia, 142290.
- Department of Microbiology, University of Tennessee, Knoxville, TN, 37996, USA.
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Alempic JM, Lartigue A, Goncharov AE, Grosse G, Strauss J, Tikhonov AN, Fedorov AN, Poirot O, Legendre M, Santini S, Abergel C, Claverie JM. An Update on Eukaryotic Viruses Revived from Ancient Permafrost. Viruses 2023; 15:v15020564. [PMID: 36851778 PMCID: PMC9958942 DOI: 10.3390/v15020564] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 02/02/2023] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
One quarter of the Northern hemisphere is underlain by permanently frozen ground, referred to as permafrost. Due to climate warming, irreversibly thawing permafrost is releasing organic matter frozen for up to a million years, most of which decomposes into carbon dioxide and methane, further enhancing the greenhouse effect. Part of this organic matter also consists of revived cellular microbes (prokaryotes, unicellular eukaryotes) as well as viruses that have remained dormant since prehistorical times. While the literature abounds on descriptions of the rich and diverse prokaryotic microbiomes found in permafrost, no additional report about "live" viruses have been published since the two original studies describing pithovirus (in 2014) and mollivirus (in 2015). This wrongly suggests that such occurrences are rare and that "zombie viruses" are not a public health threat. To restore an appreciation closer to reality, we report the preliminary characterizations of 13 new viruses isolated from seven different ancient Siberian permafrost samples, one from the Lena river and one from Kamchatka cryosol. As expected from the host specificity imposed by our protocol, these viruses belong to five different clades infecting Acanthamoeba spp. but not previously revived from permafrost: Pandoravirus, Cedratvirus, Megavirus, and Pacmanvirus, in addition to a new Pithovirus strain.
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Affiliation(s)
- Jean-Marie Alempic
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
| | - Audrey Lartigue
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
| | - Artemiy E. Goncharov
- Department of Molecular Microbiology, Institute of Experimental Medicine, Department of Epidemiology, Parasitology and Disinfectology, Northwestern State Medical Mechnikov University, Saint Petersburg 195067, Russia
| | - Guido Grosse
- Permafrost Research Section, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
- Institute of Geosciences, University of Potsdam, 14478 Potsdam, Germany
| | - Jens Strauss
- Permafrost Research Section, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
| | - Alexey N. Tikhonov
- Laboratory of Theriology, Zoological Institute of Russian Academy of Science, Saint Petersburg 199034, Russia
| | | | - Olivier Poirot
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
| | - Matthieu Legendre
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
| | - Sébastien Santini
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
| | - Chantal Abergel
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
| | - Jean-Michel Claverie
- IGS, Information Génomique & Structurale (UMR7256), Institut de Microbiologie de la Méditerranée (FR 3489), Institut Microbiologie, Bioénergies et Biotechnologie, and Institut Origines, CNRS, Aix Marseille University, 13288 Marseille, France
- Correspondence: ; Tel.: +33-413-946-777
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Keuter S, Koch H, Sass K, Wegen S, Lee N, Lücker S, Spieck E. Some like it cold: The cellular organization and physiological limits of cold-tolerant nitrite-oxidizing Nitrotoga. Environ Microbiol 2022; 24:2059-2077. [PMID: 35229435 DOI: 10.1111/1462-2920.15958] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/18/2022] [Accepted: 02/24/2022] [Indexed: 11/30/2022]
Abstract
Chemolithoautotrophic production of nitrate is accomplished by the polyphyletic functional group of nitrite-oxidizing bacteria (NOB). A widely distributed and important NOB clade in nitrogen removal processes at low temperatures is Nitrotoga, which however remains understudied due to the scarcity of cultivated representatives. Here, we present physiological, ultrastructural and genomic features of Nitrotoga strains from various habitats, including the first marine species enriched from an aquaculture system. Immunocytochemical analyses localized the nitrite-oxidizing enzyme machinery in the wide irregularly shaped periplasm, apparently without contact to the cytoplasmic membrane, confirming previous genomic data suggesting a soluble nature. Interestingly, in two strains we also observed multicellular complexes with a shared periplasmic space, which seem to form through incomplete cell division and might enhance fitness or survival. Physiological tests revealed differing tolerance limits towards dissolved inorganic nitrogen concentrations and confirmed the generally psychrotolerant nature of the genus was. Moreover, comparative analysis of 15 Nitrotoga genomes showed, e.g., a unique gene repertoire of the marine strain that could be advantageous in its natural habitat and confirmed the lack of genes for assimilatory nitrite reduction in a strain found to require ammonium for growth. Overall, these novel insights largely broaden our knowledge of Nitrotoga and elucidate the metabolic variability, physiological limits and thus potential ecological roles of this group of nitrite oxidizers. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Sabine Keuter
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Hanna Koch
- Department of Microbiology, RIBES, Radboud University, Nijmegen, the Netherlands
| | - Katharina Sass
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Simone Wegen
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Natuschka Lee
- Department of Ecology and Environmental Science and Research Infrastructure Fluorescence in situ Hybridization (FISH), Chemical Biological Centre, Umeå University, Umeå, Sweden.,Department of Microbiology, Technical University of Munich, Freising, Germany
| | - Sebastian Lücker
- Department of Microbiology, RIBES, Radboud University, Nijmegen, the Netherlands
| | - Eva Spieck
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
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Vachier J, Wettlaufer JS. Premelting controlled active matter in ice. Phys Rev E 2022; 105:024601. [PMID: 35291135 DOI: 10.1103/physreve.105.024601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
Self-propelled particles can undergo complex dynamics due to a range of bulk and surface interactions. When a particle is embedded in a host solid near its bulk melting temperature, the latter may melt at the surface of the former in a process known as interfacial premelting. The thickness of the melt film depends on the temperature, impurities, material properties and geometry. A temperature gradient is accompanied by a thermomolecular pressure gradient that drives the interfacial liquid from high to low temperatures and hence the particle from low to high temperatures, in a process called thermal regelation. When the host material is ice and the embedded particle is a biological entity, one has a particularly different form of active matter, which addresses interplay between a wide range of problems, from extremophiles of both terrestrial and exobiological relevance to ecological dynamics in Earth's cryosphere. Of basic importance in all such settings is the combined influence of biological activity and thermal regelation in controlling the redistribution of bioparticles. Therefore, we recast this class of regelation phenomena in the stochastic framework of active Ornstein-Uhlenbeck dynamics and make predictions relevant to this and related problems of interest in biological and geophysical problems. We examine how thermal regelation compromises paleoclimate studies in the context of ice core dating and we find that the activity influences particle dynamics during thermal regelation by enhancing the effective diffusion coefficient. Therefore, accurate dating relies on a quantitative treatment of both effects.
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Affiliation(s)
- Jérémy Vachier
- Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, SE-106 91 Stockholm, Sweden
| | - J S Wettlaufer
- Nordita, KTH Royal Institute of Technology and Stockholm University, Hannes Alfvéns väg 12, SE-106 91 Stockholm, Sweden
- Yale University, New Haven, Connecticut 06520-8109, USA
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8
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Antarctica as a reservoir of planetary analogue environments. Extremophiles 2021; 25:437-458. [PMID: 34586500 DOI: 10.1007/s00792-021-01245-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
One of the main objectives of astrobiological research is the investigation of the habitability of other planetary bodies. Since space exploration missions are expensive and require long-term organization, the preliminary study of terrestrial environments is an essential step to prepare and support exploration missions. The Earth hosts a multitude of extreme environments whose characteristics resemble celestial bodies in our Solar System. In these environments, the physico-chemical properties partly match extraterrestrial environments and could clarify limits and adaptation mechanisms of life, the mineralogical or geochemical context, and support and interpret data sent back from planetary bodies. One of the best terrestrial analogues is Antarctica, whose conditions lie on the edge of habitability. It is characterized by a cold and dry climate (Onofri et al., Nova Hedwigia 68:175-182, 1999), low water availability, strong katabatic winds, salt concentration, desiccation, and high radiation. Thanks to the harsh conditions like those in other celestial bodies, Antarctica offers good terrestrial analogues for celestial body (Mars or icy moons; Léveillé, CR Palevol 8:637-648, https://doi.org/10.1016/j.crpv.2009.03.005 , 2009). The continent could be distinguished into several habitats, each with characteristics similar to those existing on other bodies. Here, we reported a description of each simulated parameter within the habitats, in relation to each of the simulated extraterrestrial environments.
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Eight metagenome-assembled genomes provide evidence for microbial adaptation in 20,000 to 1,000,000-year-old Siberian permafrost. Appl Environ Microbiol 2021; 87:e0097221. [PMID: 34288700 DOI: 10.1128/aem.00972-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Permafrost microbes may be metabolically active in microscopic layers of liquid brines, even in ancient soil. Metagenomics can help discern whether permafrost microbes show adaptations to this environment. Thirty-three metagenome-assembled genomes (MAGs) were obtained from six depths (3.5 m to 20 m) of freshly-cored permafrost from the Siberia Kolyma-Indigirka Lowland region. These soils have been continuously frozen for ∼20,000 to 1,000,000 years. Eight of these MAGs were ≥80% complete with <10% contamination and were taxonomically identified as Aminicenantes, Atribacteria, Chloroflexi, and Actinobacteria within bacteria and Thermoprofundales within archaea. MAGs from these taxa have previously been obtained from non-permafrost environments and have been suggested to show adaptations to long-term energy-starvation, but they have never been explored in ancient permafrost. The permafrost MAGs had higher proportions of clusters of orthologous genes (COGs) from 'Energy production and conversion' and 'Carbohydrate transport and metabolism' than their non-permafrost counterparts. They also contained genes for trehalose synthesis, thymine metabolism, mevalonate biosynthesis and cellulose degradation that were less prevalent in non-permafrost genomes. Many of these genes are involved in membrane stabilization and osmotic stress responses, consistent with adaptation to the anoxic, high ionic strength, cold environments of permafrost brine films. Our results suggest that this ancient permafrost contains DNA in high enough quality to assemble MAGs from microorganisms with adaptations to subsist long-term freezing in this extreme environment. Importance Permafrost around the world is thawing rapidly. Many scientists from a variety of disciplines have shown the importance of understanding what will happen to our ecosystem, commerce, and climate when permafrost thaws. The fate of permafrost microorganisms is connected to these predicted rapid environmental changes. Studying ancient permafrost with culture independent techniques can give a glimpse into how these microorganisms function in these extreme low temperature and energy conditions. This will aid understanding of how they will change with the environment. This study presents genomic data from this unique environment aged ∼20,000 to 1,000,000-years-old.
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