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Savaglia V, Lambrechts S, Tytgat B, Vanhellemont Q, Elster J, Willems A, Wilmotte A, Verleyen E, Vyverman W. Geology defines microbiome structure and composition in nunataks and valleys of the Sør Rondane Mountains, East Antarctica. Front Microbiol 2024; 15:1316633. [PMID: 38380088 PMCID: PMC10877063 DOI: 10.3389/fmicb.2024.1316633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/09/2024] [Indexed: 02/22/2024] Open
Abstract
Understanding the relation between terrestrial microorganisms and edaphic factors in the Antarctic can provide insights into their potential response to environmental changes. Here we examined the composition of bacterial and micro-eukaryotic communities using amplicon sequencing of rRNA genes in 105 soil samples from the Sør Rondane Mountains (East Antarctica), differing in bedrock or substrate type and associated physicochemical conditions. Although the two most widespread taxa (Acidobacteriota and Chlorophyta) were relatively abundant in each sample, multivariate analysis and co-occurrence networks revealed pronounced differences in community structure depending on substrate type. In moraine substrates, Actinomycetota and Cercozoa were the most abundant bacterial and eukaryotic phyla, whereas on gneiss, granite and marble substrates, Cyanobacteriota and Metazoa were the dominant bacterial and eukaryotic taxa. However, at lower taxonomic level, a distinct differentiation was observed within the Cyanobacteriota phylum depending on substrate type, with granite being dominated by the Nostocaceae family and marble by the Chroococcidiopsaceae family. Surprisingly, metazoans were relatively abundant according to the 18S rRNA dataset, even in samples from the most arid sites, such as moraines in Austkampane and Widerøefjellet ("Dry Valley"). Overall, our study shows that different substrate types support distinct microbial communities, and that mineral soil diversity is a major determinant of terrestrial microbial diversity in inland Antarctic nunataks and valleys.
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Affiliation(s)
- Valentina Savaglia
- InBioS Research Unit, Department of Life Sciences, University of Liège, Liège, Belgium
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
| | - Sam Lambrechts
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Bjorn Tytgat
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
| | | | - Josef Elster
- Faculty of Science, Centre for Polar Ecology, University of South Bohemia České Budějovice and Institute of Botany, Třeboň, Czechia
| | - Anne Willems
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Annick Wilmotte
- InBioS Research Unit, Department of Life Sciences, University of Liège, Liège, Belgium
| | - Elie Verleyen
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
| | - Wim Vyverman
- Laboratory of Protistology and Aquatic Ecology, Department of Biology, Ghent University, Ghent, Belgium
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Varliero G, Lebre PH, Adams B, Chown SL, Convey P, Dennis PG, Fan D, Ferrari B, Frey B, Hogg ID, Hopkins DW, Kong W, Makhalanyane T, Matcher G, Newsham KK, Stevens MI, Weigh KV, Cowan DA. Biogeographic survey of soil bacterial communities across Antarctica. MICROBIOME 2024; 12:9. [PMID: 38212738 PMCID: PMC10785390 DOI: 10.1186/s40168-023-01719-3] [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: 07/07/2023] [Accepted: 11/11/2023] [Indexed: 01/13/2024]
Abstract
BACKGROUND Antarctica and its unique biodiversity are increasingly at risk from the effects of global climate change and other human influences. A significant recent element underpinning strategies for Antarctic conservation has been the development of a system of Antarctic Conservation Biogeographic Regions (ACBRs). The datasets supporting this classification are, however, dominated by eukaryotic taxa, with contributions from the bacterial domain restricted to Actinomycetota and Cyanobacteriota. Nevertheless, the ice-free areas of the Antarctic continent and the sub-Antarctic islands are dominated in terms of diversity by bacteria. Our study aims to generate a comprehensive phylogenetic dataset of Antarctic bacteria with wide geographical coverage on the continent and sub-Antarctic islands, to investigate whether bacterial diversity and distribution is reflected in the current ACBRs. RESULTS Soil bacterial diversity and community composition did not fully conform with the ACBR classification. Although 19% of the variability was explained by this classification, the largest differences in bacterial community composition were between the broader continental and maritime Antarctic regions, where a degree of structural overlapping within continental and maritime bacterial communities was apparent, not fully reflecting the division into separate ACBRs. Strong divergence in soil bacterial community composition was also apparent between the Antarctic/sub-Antarctic islands and the Antarctic mainland. Bacterial communities were partially shaped by bioclimatic conditions, with 28% of dominant genera showing habitat preferences connected to at least one of the bioclimatic variables included in our analyses. These genera were also reported as indicator taxa for the ACBRs. CONCLUSIONS Overall, our data indicate that the current ACBR subdivision of the Antarctic continent does not fully reflect bacterial distribution and diversity in Antarctica. We observed considerable overlap in the structure of soil bacterial communities within the maritime Antarctic region and within the continental Antarctic region. Our results also suggest that bacterial communities might be impacted by regional climatic and other environmental changes. The dataset developed in this study provides a comprehensive baseline that will provide a valuable tool for biodiversity conservation efforts on the continent. Further studies are clearly required, and we emphasize the need for more extensive campaigns to systematically sample and characterize Antarctic and sub-Antarctic soil microbial communities. Video Abstract.
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Affiliation(s)
- Gilda Varliero
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, 0002, South Africa
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Pedro H Lebre
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, 0002, South Africa
| | - Byron Adams
- Department of Biology, Brigham Young University, Provo, UT, 84602, USA
- Monte L. Bean Life Science Museum, Brigham Young University, Provo, UT, 84602, USA
| | - Steven L Chown
- Securing Antarctica's Environmental Future, School of Biological Sciences, Monash University, Clayton, VA, 3800, Australia
| | - Peter Convey
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
- Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006, South Africa
- Biodiversity of Antarctic and Sub-Antarctic Ecosystems (BASE), Santiago, Chile
| | - Paul G Dennis
- School of the Environment, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Dandan Fan
- State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Belinda Ferrari
- School of Biotechnology and Biomolecular Sciences, University of NSW, Sydney, NSW, 2052, Australia
| | - Beat Frey
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
| | - Ian D Hogg
- School of Science, University of Waikato, Hamilton, New Zealand
- Canadian High Arctic Research Station, Polar Knowledge Canada, Cambridge Bay, NU, Canada
| | - David W Hopkins
- SRUC - Scotland's Rural College, West Mains Road, Edinburgh, EH9 3JG, Scotland, UK
| | - Weidong Kong
- State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources (TPESER), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Thulani Makhalanyane
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - Gwynneth Matcher
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda, South Africa
| | - Kevin K Newsham
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
| | - Mark I Stevens
- Securing Antarctica's Environmental Future, Earth and Biological Sciences, South Australian Museum, Adelaide, SA, 5000, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Katherine V Weigh
- School of the Environment, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Don A Cowan
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, 0002, South Africa.
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Griffiths HJ, Whittle RJ, Mitchell EG. Animal survival strategies in Neoproterozoic ice worlds. GLOBAL CHANGE BIOLOGY 2023; 29:10-20. [PMID: 36220153 PMCID: PMC10091762 DOI: 10.1111/gcb.16393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/25/2022] [Accepted: 08/09/2022] [Indexed: 06/16/2023]
Abstract
The timing of the first appearance of animals is of crucial importance for understanding the evolution of life on Earth. Although the fossil record places the earliest metazoans at 572-602 Ma, molecular clock studies suggest a far earlier origination, as far back as ~850 Ma. The difference in these dates would place the rise of animal life into a time period punctuated by multiple colossal, potentially global, glacial events. Although the two schools of thought debate the limitations of each other's methods, little time has been dedicated to how animal life might have survived if it did arise before or during these global glacial periods. The history of recent polar biota shows that organisms have found ways of persisting on and around the ice of the Antarctic continent throughout the Last Glacial Maximum (33-14 Ka), with some endemic species present before the breakup of Gondwana (180-23 Ma). Here we discuss the survival strategies and habitats of modern polar marine organisms in environments analogous to those that could have existed during Neoproterozoic glaciations. We discuss how, despite the apparent harshness of many ice covered, sub-zero, Antarctic marine habitats, animal life thrives on, in and under the ice. Ice dominated systems and processes make some local environments more habitable through water circulation, oxygenation, terrigenous nutrient input and novel habitats. We consider how the physical conditions of Neoproterozoic glaciations would likely have dramatically impacted conditions for potential life in the shallows and erased any possible fossil evidence from the continental shelves. The recent glacial cycle has driven the evolution of Antarctica's unique fauna by acting as a "diversity pump," and the same could be true for the late Proterozoic and the evolution of animal life on Earth, and the existence of life elsewhere in the universe on icy worlds or moons.
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