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Purcell AM, Dijkstra P, Hungate BA, McMillen K, Schwartz E, van Gestel N. Rapid growth rate responses of terrestrial bacteria to field warming on the Antarctic Peninsula. THE ISME JOURNAL 2023; 17:2290-2302. [PMID: 37872274 PMCID: PMC10689830 DOI: 10.1038/s41396-023-01536-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023]
Abstract
Ice-free terrestrial environments of the western Antarctic Peninsula are expanding and subject to colonization by new microorganisms and plants, which control biogeochemical cycling. Measuring growth rates of microbial populations and ecosystem carbon flux is critical for understanding how terrestrial ecosystems in Antarctica will respond to future warming. We implemented a field warming experiment in early (bare soil; +2 °C) and late (peat moss-dominated; +1.2 °C) successional glacier forefield sites on the western Antarctica Peninsula. We used quantitative stable isotope probing with H218O using intact cores in situ to determine growth rate responses of bacterial taxa to short-term (1 month) warming. Warming increased the growth rates of bacterial communities at both sites, even doubling the number of taxa exhibiting significant growth at the early site. Growth responses varied among taxa. Despite that warming induced a similar response for bacterial relative growth rates overall, the warming effect on ecosystem carbon fluxes was stronger at the early successional site-likely driven by increased activity of autotrophs which switched the ecosystem from a carbon source to a carbon sink. At the late-successional site, warming caused a significant increase in growth rate of many Alphaproteobacteria, but a weaker and opposite gross ecosystem productivity response that decreased the carbon sink-indicating that the carbon flux rates were driven more strongly by the plant communities. Such changes to bacterial growth and ecosystem carbon cycling suggest that the terrestrial Antarctic Peninsula can respond fast to increases in temperature, which can have repercussions for long-term elemental cycling and carbon storage.
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Affiliation(s)
- Alicia M Purcell
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
| | - Paul Dijkstra
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Bruce A Hungate
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Kelly McMillen
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Egbert Schwartz
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Natasja van Gestel
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
- TTU Climate Center, Texas Tech University, Lubbock, TX, USA
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Yin H, Perera-Castro AV, Randall KL, Turnbull JD, Waterman MJ, Dunn J, Robinson SA. Basking in the sun: how mosses photosynthesise and survive in Antarctica. PHOTOSYNTHESIS RESEARCH 2023; 158:151-169. [PMID: 37515652 PMCID: PMC10684656 DOI: 10.1007/s11120-023-01040-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/10/2023] [Indexed: 07/31/2023]
Abstract
The Antarctic environment is extremely cold, windy and dry. Ozone depletion has resulted in increasing ultraviolet-B radiation, and increasing greenhouse gases and decreasing stratospheric ozone have altered Antarctica's climate. How do mosses thrive photosynthetically in this harsh environment? Antarctic mosses take advantage of microclimates where the combination of protection from wind, sufficient melt water, nutrients from seabirds and optimal sunlight provides both photosynthetic energy and sufficient warmth for efficient metabolism. The amount of sunlight presents a challenge: more light creates warmer canopies which are optimal for photosynthetic enzymes but can contain excess light energy that could damage the photochemical apparatus. Antarctic mosses thus exhibit strong photoprotective potential in the form of xanthophyll cycle pigments. Conversion to zeaxanthin is high when conditions are most extreme, especially when water content is low. Antarctic mosses also produce UV screening compounds which are maintained in cell walls in some species and appear to protect from DNA damage under elevated UV-B radiation. These plants thus survive in one of the harshest places on Earth by taking advantage of the best real estate to optimise their metabolism. But survival is precarious and it remains to be seen if these strategies will still work as the Antarctic climate changes.
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Affiliation(s)
- Hao Yin
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | | | - Krystal L Randall
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Johanna D Turnbull
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Melinda J Waterman
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Jodie Dunn
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Sharon A Robinson
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, 2522, Australia.
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia.
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Strugnell JM, McGregor HV, Wilson NG, Meredith KT, Chown SL, Lau SCY, Robinson SA, Saunders KM. Emerging biological archives can reveal ecological and climatic change in Antarctica. GLOBAL CHANGE BIOLOGY 2022; 28:6483-6508. [PMID: 35900301 PMCID: PMC9826052 DOI: 10.1111/gcb.16356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Anthropogenic climate change is causing observable changes in Antarctica and the Southern Ocean including increased air and ocean temperatures, glacial melt leading to sea-level rise and a reduction in salinity, and changes to freshwater water availability on land. These changes impact local Antarctic ecosystems and the Earth's climate system. The Antarctic has experienced significant past environmental change, including cycles of glaciation over the Quaternary Period (the past ~2.6 million years). Understanding Antarctica's paleoecosystems, and the corresponding paleoenvironments and climates that have shaped them, provides insight into present day ecosystem change, and importantly, helps constrain model projections of future change. Biological archives such as extant moss beds and peat profiles, biological proxies in lake and marine sediments, vertebrate animal colonies, and extant terrestrial and benthic marine invertebrates, complement other Antarctic paleoclimate archives by recording the nature and rate of past ecological change, the paleoenvironmental drivers of that change, and constrain current ecosystem and climate models. These archives provide invaluable information about terrestrial ice-free areas, a key location for Antarctic biodiversity, and the continental margin which is important for understanding ice sheet dynamics. Recent significant advances in analytical techniques (e.g., genomics, biogeochemical analyses) have led to new applications and greater power in elucidating the environmental records contained within biological archives. Paleoecological and paleoclimate discoveries derived from biological archives, and integration with existing data from other paleoclimate data sources, will significantly expand our understanding of past, present, and future ecological change, alongside climate change, in a unique, globally significant region.
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Affiliation(s)
- Jan M. Strugnell
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
- Securing Antarctica's Environmental FutureJames Cook UniversityTownsvilleQueenslandAustralia
| | - Helen V. McGregor
- Securing Antarctica's Environmental Future, School of Earth, Atmospheric and Life SciencesUniversity of WollongongWollongongNew South WalesAustralia
| | - Nerida G. Wilson
- Securing Antarctica's Environmental FutureWestern Australian MuseumWestern AustraliaAustralia
- Research and CollectionsWestern Australian MuseumWestern AustraliaAustralia
- School of Biological SciencesUniversity of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Karina T. Meredith
- Securing Antarctica's Environmental FutureAustralian Nuclear Science and Technology OrganisationLucas HeightsNew South WalesAustralia
| | - Steven L. Chown
- Securing Antarctica's Environmental Future, School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Sally C. Y. Lau
- Centre for Sustainable Tropical Fisheries and Aquaculture and College of Science and EngineeringJames Cook UniversityTownsvilleQueenslandAustralia
- Securing Antarctica's Environmental FutureJames Cook UniversityTownsvilleQueenslandAustralia
| | - Sharon A. Robinson
- Securing Antarctica's Environmental Future, School of Earth, Atmospheric and Life SciencesUniversity of WollongongWollongongNew South WalesAustralia
| | - Krystyna M. Saunders
- Securing Antarctica's Environmental Future, School of Earth, Atmospheric and Life SciencesUniversity of WollongongWollongongNew South WalesAustralia
- Securing Antarctica's Environmental FutureAustralian Nuclear Science and Technology OrganisationLucas HeightsNew South WalesAustralia
- Institute for Marine and Antarctic StudiesUniversity of TasmaniaHobartTasmaniaAustralia
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