Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity
Ice-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited t...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2021-01-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmicb.2021.616730/full |
| _version_ | 1819283152157278208 |
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| author | Scott F. George Noah Fierer Joseph S. Levy Byron Adams Byron Adams |
| author_facet | Scott F. George Noah Fierer Joseph S. Levy Byron Adams Byron Adams |
| author_sort | Scott F. George |
| collection | DOAJ |
| description | Ice-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited to investigate environmental and spatial influences on bacterial community structure. Water tracks are annually wetted habitats in the cold-arid soils of Antarctica that form briefly each summer with moisture sourced from snow melt, ground ice thaw, and atmospheric deposition via deliquescence and vapor flow into brines. Compared to neighboring arid soils, water tracks are highly saline and relatively moist habitats. They represent a considerable area (∼5–10 km2) of the Dry Valley terrestrial ecosystem, an area that is expected to increase with ongoing climate change. The goal of this study was to determine how variation in the environmental conditions of water tracks influences the composition and diversity of microbial communities. We found significant differences in microbial community composition between on- and off-water track samples, and across two distinct locations. Of the tested environmental variables, soil salinity was the best predictor of community composition, with members of the Bacteroidetes phylum being relatively more abundant at higher salinities and the Actinobacteria phylum showing the opposite pattern. There was also a significant, inverse relationship between salinity and bacterial diversity. Our results suggest water track formation significantly alters dry soil microbial communities, likely influencing subsequent ecosystem functioning. We highlight how Dry Valley water tracks could be a useful model system for understanding the potential habitability of transiently wetted environments found on the surface of Mars. |
| first_indexed | 2024-12-24T01:26:56Z |
| format | Article |
| id | doaj.art-216ea186fec5481097345c62fe78bdc9 |
| institution | Directory Open Access Journal |
| issn | 1664-302X |
| language | English |
| last_indexed | 2024-12-24T01:26:56Z |
| publishDate | 2021-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Microbiology |
| spelling | doaj.art-216ea186fec5481097345c62fe78bdc92022-12-21T17:22:29ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2021-01-011210.3389/fmicb.2021.616730616730Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and SalinityScott F. George0Noah Fierer1Joseph S. Levy2Byron Adams3Byron Adams4Department of Biology, Brigham Young University, Provo, UT, United StatesDepartment of Ecology and Evolutionary Biology and Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, United StatesDepartment of Geology, Colgate University, Hamilton, NY, United StatesDepartment of Biology, Brigham Young University, Provo, UT, United StatesMonte L. Bean Museum, Brigham Young University, Provo, UT, United StatesIce-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited to investigate environmental and spatial influences on bacterial community structure. Water tracks are annually wetted habitats in the cold-arid soils of Antarctica that form briefly each summer with moisture sourced from snow melt, ground ice thaw, and atmospheric deposition via deliquescence and vapor flow into brines. Compared to neighboring arid soils, water tracks are highly saline and relatively moist habitats. They represent a considerable area (∼5–10 km2) of the Dry Valley terrestrial ecosystem, an area that is expected to increase with ongoing climate change. The goal of this study was to determine how variation in the environmental conditions of water tracks influences the composition and diversity of microbial communities. We found significant differences in microbial community composition between on- and off-water track samples, and across two distinct locations. Of the tested environmental variables, soil salinity was the best predictor of community composition, with members of the Bacteroidetes phylum being relatively more abundant at higher salinities and the Actinobacteria phylum showing the opposite pattern. There was also a significant, inverse relationship between salinity and bacterial diversity. Our results suggest water track formation significantly alters dry soil microbial communities, likely influencing subsequent ecosystem functioning. We highlight how Dry Valley water tracks could be a useful model system for understanding the potential habitability of transiently wetted environments found on the surface of Mars.https://www.frontiersin.org/articles/10.3389/fmicb.2021.616730/fullAntarcticaMars analogwater tracksmicrobial ecologyextremophiles |
| spellingShingle | Scott F. George Noah Fierer Joseph S. Levy Byron Adams Byron Adams Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity Frontiers in Microbiology Antarctica Mars analog water tracks microbial ecology extremophiles |
| title | Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity |
| title_full | Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity |
| title_fullStr | Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity |
| title_full_unstemmed | Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity |
| title_short | Antarctic Water Tracks: Microbial Community Responses to Variation in Soil Moisture, pH, and Salinity |
| title_sort | antarctic water tracks microbial community responses to variation in soil moisture ph and salinity |
| topic | Antarctica Mars analog water tracks microbial ecology extremophiles |
| url | https://www.frontiersin.org/articles/10.3389/fmicb.2021.616730/full |
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