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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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Mashamaite L, Lebre PH, Varliero G, Maphosa S, Ortiz M, Hogg ID, Cowan DA. Microbial diversity in Antarctic Dry Valley soils across an altitudinal gradient. Front Microbiol 2023; 14:1203216. [PMID: 37555066 PMCID: PMC10406297 DOI: 10.3389/fmicb.2023.1203216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/23/2023] [Indexed: 08/10/2023] Open
Abstract
INTRODUCTION The Antarctic McMurdo Dry Valleys are geologically diverse, encompassing a wide variety of soil habitats. These environments are largely dominated by microorganisms, which drive the ecosystem services of the region. While altitude is a well-established driver of eukaryotic biodiversity in these Antarctic ice-free areas (and many non-Antarctic environments), little is known of the relationship between altitude and microbial community structure and functionality in continental Antarctica. METHODS We analysed prokaryotic and lower eukaryotic diversity from soil samples across a 684 m altitudinal transect in the lower Taylor Valley, Antarctica and performed a phylogenic characterization of soil microbial communities using short-read sequencing of the 16S rRNA and ITS marker gene amplicons. RESULTS AND DISCUSSION Phylogenetic analysis showed clear altitudinal trends in soil microbial composition and structure. Cyanobacteria were more prevalent in higher altitude samples, while the highly stress resistant Chloroflexota and Deinococcota were more prevalent in lower altitude samples. We also detected a shift from Basidiomycota to Chytridiomycota with increasing altitude. Several genera associated with trace gas chemotrophy, including Rubrobacter and Ornithinicoccus, were widely distributed across the entire transect, suggesting that trace-gas chemotrophy may be an important trophic strategy for microbial survival in oligotrophic environments. The ratio of trace-gas chemotrophs to photoautotrophs was significantly higher in lower altitude samples. Co-occurrence network analysis of prokaryotic communities showed some significant differences in connectivity within the communities from different altitudinal zones, with cyanobacterial and trace-gas chemotrophy-associated taxa being identified as potential keystone taxa for soil communities at higher altitudes. By contrast, the prokaryotic network at low altitudes was dominated by heterotrophic keystone taxa, thus suggesting a clear trophic distinction between soil prokaryotic communities at different altitudes. Based on these results, we conclude that altitude is an important driver of microbial ecology in Antarctic ice-free soil habitats.
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Affiliation(s)
- Lefentse Mashamaite
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Pedro H. Lebre
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Gilda Varliero
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Silindile Maphosa
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
| | - Max Ortiz
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
- Clemson University Genomics & Bioinformatics Facility, Clemson University, Clemson, SC, United States
| | - Ian D. Hogg
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
- School of Science, University of Waikato, Hamilton, New Zealand
- Canadian High Arctic Research Station, Polar Knowledge Canada, Cambridge Bay, NU, Canada
| | - Don A. Cowan
- Department of Biochemistry, Genetics and Microbiology, Centre for Microbial Ecology and Genomics, University of Pretoria, Pretoria, South Africa
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