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Francis Justine M, Kaiwen P, Tadesse Z, Hongyan Z, Lin Z. Cooling has stimulated soil carbon storage in forest ecosystems. ENVIRONMENTAL RESEARCH 2024; 245:118012. [PMID: 38154564 DOI: 10.1016/j.envres.2023.118012] [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: 09/18/2023] [Revised: 11/14/2023] [Accepted: 12/21/2023] [Indexed: 12/30/2023]
Abstract
The interactive effect of soil cooling and nitrogen (N) addition can accurately simulate climatic and anthropogenic effects on terrestrial and other land-based ecosystems, but direct empirical measurements on the effects of cooling and N addition on soil carbon (C) and N are lacking. Hence, transplanting soils into colder regions was used to evaluate the effects of cooling and N addition on soil C and N. We used PVCs of 30 cm in height and 8 cm in diameter to extract soil samples. Soil C and N were significantly (P < 0.05) increased by transplanting soils into colder regions. In contrast, cooling has insignificantly (P > 0.05) increased the soil dissolved organic C (DOC) and dissolved organic (DON), but the effect was negatively significant on soil pH compared to the C/N ratio. Similarly, N addition significantly increased the measured soil N stock. However, the effect was negatively significant on soil pH (P < 0.05) compared to the C/N ratio (P > 0.05). Nevertheless, the interaction of cooling and N addition did not affect the soil C and N storage. A similar effect was observed on the soil DOC and DON. The results presented here illustrate that transplanting soils into colder regions and N deposition has perfectly simulated the effects of climate-forcing factors on soil C and N storage in terrestrial and other land-based ecosystems. Accordingly, this study suggests that low temperatures have stimulated the accumulation of the measured soil organic and dissolved properties, but the effect is less consequential when low temperature interacts with N addition in high-elevation areas where ecosystem structures and functions are limited by temperature and may serve as a baseline for future research on land feedbacks to the climate system.
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Affiliation(s)
- Meta Francis Justine
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration of Biodiversity Conservation, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China; International College, University of Chinese Academy of Sciences, Beijing, 100049, China; Ministry of Environment and Forestry, Juba, South Sudan
| | - Pan Kaiwen
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration of Biodiversity Conservation, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Zebene Tadesse
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration of Biodiversity Conservation, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China; International College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhou Hongyan
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration of Biodiversity Conservation, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China; International College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhang Lin
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization and Ecological Restoration of Biodiversity Conservation, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China.
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2
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Kaplan Pastíriková L, Hrbáček F, Uxa T, Láska K. Permafrost table temperature and active layer thickness variability on James Ross Island, Antarctic Peninsula, in 2004-2021. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161690. [PMID: 36657667 DOI: 10.1016/j.scitotenv.2023.161690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/22/2022] [Accepted: 01/14/2023] [Indexed: 06/17/2023]
Abstract
Climate change and its impacts on sensitive polar ecosystems are relatively little studied in Antarctic regions. Permafrost and active layer changes over time in periglacial regions of the world are important indicators of climate variability. These changes (e. g. permafrost degradation, increasing of the active layer thickness) can have a significant impact on Antarctic terrestrial ecosystems. The study site (AWS-JGM) is located on the Ulu Peninsula in the north of James Ross Island. Ground temperatures at depths of 5, 50, and 75 cm have been measured at the site since 2011, while air temperature began to be measured in 2004. The main objective is to evaluate the year-to-year variability of the reconstructed temperature of the top of the permafrost table and the active layer thickness (ALT) since 2004 based on air temperature data using TTOP and Stefan models, respectively. The models were verified against direct observations from a reference period 2011/12-2020/21 showing a strong correlation of 0.95 (RMSE = 0.52) and 0.84 (RMSE = 3.54) for TTOP and Stefan models, respectively. The reconstructed average temperature of the permafrost table for the period 2004/05-2020/21 was -5.8 °C with a trend of -0.1 °C/decade, while the average air temperature reached -6.6 °C with a trend of 0.6 °C/decade. Air temperatures did not have an increasing trend throughout the period, but in the first part of the period (2004/05-2010/11) showed a decreasing tendency (-1.3 °C/decade). In the period 2011/12-2020/21, it was a warming of 1.9 °C/decade. The average modelled ALT for the period 2004/05-2020/21 reached a value of 60cm with a trend of -1.6 cm/decade. Both models were found to provide reliable results, and thus they significantly expand the information about the permafrost and ALT, which is necessary for a better understanding of their spatiotemporal variability and the impact of climate change on the cryosphere.
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Affiliation(s)
| | - Filip Hrbáček
- Department of Geography, Masaryk University, Brno, Czech Republic
| | - Tomáš Uxa
- Institute of Geophysics, Czech Academy of Sciences, Prague, Czech Republic
| | - Kamil Láska
- Department of Geography, Masaryk University, Brno, Czech Republic
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3
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Zoumplis A, Kolody B, Kaul D, Zheng H, Venepally P, McKnight DM, Takacs-Vesbach C, DeVries A, Allen AE. Impact of meltwater flow intensity on the spatiotemporal heterogeneity of microbial mats in the McMurdo Dry Valleys, Antarctica. ISME COMMUNICATIONS 2023; 3:3. [PMID: 36690784 PMCID: PMC9870883 DOI: 10.1038/s43705-022-00202-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 11/13/2022] [Accepted: 11/16/2022] [Indexed: 01/24/2023]
Abstract
The meltwater streams of the McMurdo Dry Valleys are hot spots of biological diversity in the climate-sensitive polar desert landscape. Microbial mats, largely comprised of cyanobacteria, dominate the streams which flow for a brief window of time (~10 weeks) over the austral summer. These communities, critical to nutrient and carbon cycling, display previously uncharacterized patterns of rapid destabilization and recovery upon exposure to variable and physiologically detrimental conditions. Here, we characterize changes in biodiversity, transcriptional responses and activity of microbial mats in response to hydrological disturbance over spatiotemporal gradients. While diverse metabolic strategies persist between marginal mats and main channel mats, data collected from 4 time points during the austral summer revealed a homogenization of the mat communities during the mid-season peak meltwater flow, directly influencing the biogeochemical roles of this stream ecosystem. Gene expression pattern analyses identified strong functional sensitivities of nitrogen-fixing marginal mats to changes in hydrological activities. Stress response markers detailed the environmental challenges of each microhabitat and the molecular mechanisms underpinning survival in a polar desert ecosystem at the forefront of climate change. At mid and end points in the flow cycle, mobile genetic elements were upregulated across all mat types indicating high degrees of genome evolvability and transcriptional synchronies. Additionally, we identified novel antifreeze activity in the stream microbial mats indicating the presence of ice-binding proteins (IBPs). Cumulatively, these data provide a new view of active intra-stream diversity, biotic interactions and alterations in ecosystem function over a high-flow hydrological regime.
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Affiliation(s)
- A Zoumplis
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - B Kolody
- Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - D Kaul
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - H Zheng
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - P Venepally
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA
| | - D M McKnight
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
| | - C Takacs-Vesbach
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - A DeVries
- Evolution, Ecology and Behavior, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - A E Allen
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA.
- Microbial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA, USA.
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4
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Hudson AR, Peters DPC, Blair JM, Childers DL, Doran PT, Geil K, Gooseff M, Gross KL, Haddad NM, Pastore MA, Rudgers JA, Sala O, Seabloom EW, Shaver G. Cross-Site Comparisons of Dryland Ecosystem Response to Climate Change in the US Long-Term Ecological Research Network. Bioscience 2022; 72:889-907. [PMID: 36034512 PMCID: PMC9405733 DOI: 10.1093/biosci/biab134] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Long-term observations and experiments in diverse drylands reveal how ecosystems and services are responding to climate change. To develop generalities about climate change impacts at dryland sites, we compared broadscale patterns in climate and synthesized primary production responses among the eight terrestrial, nonforested sites of the United States Long-Term Ecological Research (US LTER) Network located in temperate (Southwest and Midwest) and polar (Arctic and Antarctic) regions. All sites experienced warming in recent decades, whereas drought varied regionally with multidecadal phases. Multiple years of wet or dry conditions had larger effects than single years on primary production. Droughts, floods, and wildfires altered resource availability and restructured plant communities, with greater impacts on primary production than warming alone. During severe regional droughts, air pollution from wildfire and dust events peaked. Studies at US LTER drylands over more than 40 years demonstrate reciprocal links and feedbacks among dryland ecosystems, climate-driven disturbance events, and climate change.
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Affiliation(s)
- Amy R Hudson
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
| | - Debra P C Peters
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
- US Department of Agriculture Agricultural Research Service's Jornada Experimental Range, Las Cruces , New Mexico, United States
- New Mexico State University , Las Cruces, New Mexico, United States
| | - John M Blair
- Kansas State University, Manhattan , Kansas, United States
| | | | - Peter T Doran
- Louisiana State University , Baton Rouge, Louisiana, United States
| | - Kerrie Geil
- Agricultural Research Service's Big Data Initiative and SCINet Program for Scientific Computing in Berwyn Heights , Maryland, United States
| | | | - Katherine L Gross
- W. K. Kellogg Biological Station, Vermont , United States
- Department of Plant Biology, Vermont , United States
| | - Nick M Haddad
- W. K. Kellogg Biological Station, Vermont , United States
- Department of Plant Biology, Vermont , United States
| | | | | | - Osvaldo Sala
- Arizona State University , Tempe, Arizona, United States
- Global Drylands Center and the School of Life Sciences, Arizona State University , Tempe, Arizona, United States
| | - Eric W Seabloom
- University of Minnesota , St. Paul, Minnesota, United States
| | - Gaius Shaver
- Marine Biological Laboratory, Woods Hole , Massachusetts, United States
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5
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OUP accepted manuscript. Bioscience 2022. [DOI: 10.1093/biosci/biac034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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6
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Awasthi A, Vishwakarma K, Pattnayak KC. Retrospection of heatwave and heat index. THEORETICAL AND APPLIED CLIMATOLOGY 2022; 147:589-604. [PMID: 34785831 PMCID: PMC8581126 DOI: 10.1007/s00704-021-03854-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/29/2021] [Indexed: 05/21/2023]
Abstract
The frequency and intensity of extreme events especially heat waves (HW) are growing all around the world which ultimately poses a serious threat to the health of individuals. To quantify the effects of extreme temperature, appropriate information, and the importance of HW and heat index (HI) are carefully discussed for different parts of the world. Varied definitions of the HW and HI formula proposed and used by different countries are carried out systematically continent-wise. Different studies highlighted the number of definitions of HW; however, mostly used Steadman's formulae, which was developed in the late 1970s, for the calculation of HI that uses surface air temperature and relative humidity as climatic fields. Since then, dramatic changes in climatic conditions have been observed as evident from the ERA5 datasets which need to be addressed; likewise, the definition of HW, which is modified by the researchers as per the geographic conditions. It is evident from the ERA5 data that the temperature has increased by 1-2 °C as compared to the 1980s. There is a threefold increase in the number of heatwave days over most of the continents in the last 40 years. This study will help the researcher community to understand the importance of HW and HI. Furthermore, it opens the scope to develop an equation based on the present scenario keeping in mind the basics of an index as considered by Steadman.
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Affiliation(s)
- Amit Awasthi
- Department of Applied Sciences, University of Petroleum & Energy Studies, Dehradun, 248007 Uttarakhand India
| | - Kirti Vishwakarma
- Department of Aerospace Engineering, University of Petroleum & Energy Studies, Dehradun, Uttarakhand India
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Franco ALC, Adams BJ, Diaz MA, Lemoine NP, Dragone NB, Fierer N, Lyons WB, Hogg I, Wall DH. Response of Antarctic soil fauna to climate-driven changes since the Last Glacial Maximum. GLOBAL CHANGE BIOLOGY 2022; 28:644-653. [PMID: 34657350 DOI: 10.1111/gcb.15940] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
Understanding how terrestrial biotic communities have responded to glacial recession since the Last Glacial Maximum (LGM) can inform present and future responses of biota to climate change. In Antarctica, the Transantarctic Mountains (TAM) have experienced massive environmental changes associated with glacial retreat since the LGM, yet we have few clues as to how its soil invertebrate-dominated animal communities have responded. Here, we surveyed soil invertebrate fauna from above and below proposed LGM elevations along transects located at 12 features across the Shackleton Glacier region. Our transects captured gradients of surface ages possibly up to 4.5 million years and the soils have been free from human disturbance for their entire history. Our data support the hypothesis that soils exposed during the LGM are now less suitable habitats for invertebrates than those that have been exposed by deglaciation following the LGM. Our results show that faunal abundance, community composition, and diversity were all strongly affected by climate-driven changes since the LGM. Soils more recently exposed by the glacial recession (as indicated by distances from present ice surfaces) had higher faunal abundances and species richness than older exposed soils. Higher abundances of the dominant nematode Scottnema were found in older exposed soils, while Eudorylaimus, Plectus, tardigrades, and rotifers preferentially occurred in more recently exposed soils. Approximately 30% of the soils from which invertebrates could be extracted had only Scottnema, and these single-taxon communities occurred more frequently in soils exposed for longer periods of time. Our structural equation modeling of abiotic drivers highlighted soil salinity as a key mediator of Scottnema responses to soil exposure age. These changes in soil habitat suitability and biotic communities since the LGM indicate that Antarctic terrestrial biodiversity throughout the TAM will be highly altered by climate warming.
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Affiliation(s)
- André L C Franco
- Department of Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Byron J Adams
- Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum Provo, Brigham Young University, Provo, Utah, USA
| | - Melisa A Diaz
- School of Earth Sciences, Byrd Polar and Climate Research Center Columbus, The Ohio State University, Columbus, Ohio, USA
| | - Nathan P Lemoine
- Department of Biological Sciences Milwaukee, Marquette University, Milwaukee, Wisconsin, USA
- Milwaukee Public Museum Department of Zoology Milwaukee, Milwaukee, Wisconsin, USA
| | - Nicholas B Dragone
- Department of Ecology and Evolutionary Biology, and Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - Noah Fierer
- Department of Ecology and Evolutionary Biology, and Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
| | - W Berry Lyons
- School of Earth Sciences, Byrd Polar and Climate Research Center Columbus, The Ohio State University, Columbus, Ohio, USA
| | - Ian Hogg
- Canadian High Arctic Research Station, Polar Knowledge Canada, Cambridge Bay, Nunavut, Canada
- School of Science, University of Waikato, Hamilton, New Zealand
| | - Diana H Wall
- Department of Biology & School of Global Environmental Sustainability, Colorado State University, Fort Collins, Colorado, USA
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Kemppinen J, Niittynen P, le Roux PC, Momberg M, Happonen K, Aalto J, Rautakoski H, Enquist BJ, Vandvik V, Halbritter AH, Maitner B, Luoto M. Consistent trait-environment relationships within and across tundra plant communities. Nat Ecol Evol 2021; 5:458-467. [PMID: 33633373 DOI: 10.1038/s41559-021-01396-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 01/19/2021] [Indexed: 01/31/2023]
Abstract
A fundamental assumption in trait-based ecology is that relationships between traits and environmental conditions are globally consistent. We use field-quantified microclimate and soil data to explore if trait-environment relationships are generalizable across plant communities and spatial scales. We collected data from 6,720 plots and 217 species across four distinct tundra regions from both hemispheres. We combined these data with over 76,000 database trait records to relate local plant community trait composition to broad gradients of key environmental drivers: soil moisture, soil temperature, soil pH and potential solar radiation. Results revealed strong, consistent trait-environment relationships across Arctic and Antarctic regions. This indicates that the detected relationships are transferable between tundra plant communities also when fine-scale environmental heterogeneity is accounted for, and that variation in local conditions heavily influences both structural and leaf economic traits. Our results strengthen the biological and mechanistic basis for climate change impact predictions of vulnerable high-latitude ecosystems.
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Affiliation(s)
| | | | | | - Mia Momberg
- University of Pretoria, Pretoria, South Africa
| | | | - Juha Aalto
- Finnish Meteorological Institute, Helsinki, Finland
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9
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Hawes I, Howard-Williams C, Gilbert N, Joy K. Towards an Environmental Classification of Lentic Aquatic Ecosystems in the McMurdo Dry Valleys, Antarctica. ENVIRONMENTAL MANAGEMENT 2021; 67:600-622. [PMID: 33559688 DOI: 10.1007/s00267-021-01438-1] [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: 12/03/2020] [Accepted: 01/22/2021] [Indexed: 06/12/2023]
Abstract
The McMurdo Dry Valleys are the largest single ice-free area in Antarctica, and of considerable scientific and conservation value as an extreme polar desert. This is recognised through the McMurdo Dry Valleys Antarctic Specially Managed Area (ASMA), where management's goals focus on protection of its unique features, while facilitating science access. Using a mix of remote sensing and existing cartography, we have identified over 6000 lakes and ponds in the ASMA. This study develops a classification of those aquatic ecosystems to provide a framework for management. It uses a limited top-down, hierarchical classification to define 13 class separations based on physical attributes that could largely be ascribed from existing databases or remotely sensed information. The first hierarchical level was based on landscape position, separating coastal kettle holes (reflecting recent glacial history), from other "topographic" water bodies. The second level was based on endorheic vs exorheic drainage, the third on mid-summer ice condition (no-ice cap; ice capped; frozen to base) and the fourth on source of inflow (glacial or non-glacial). Kettles were sub-classed by mid-summer ice only. Classes were tested against a set of field observations and an expert workshop validation process considered management implications for the ASMA. This study shows how the classification assists our understanding of Dry Valley landscapes and addresses management issues faced by researchers, environmental managers and policy makers. The approach to classification, rather than the detailed classes that may be specific to the Dry Valleys, has potential for wider use in other polar landscapes.
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Affiliation(s)
- Ian Hawes
- Coastal Marine Field Station, University of Waikato, 58 Cross Road, Sulphur Point, Tauranga, 3110, New Zealand.
| | - Clive Howard-Williams
- National Institute of Water and Atmospheric Research, Lt Box 8602, Christchurch, New Zealand
| | - Neil Gilbert
- Constantia Consulting Ltd, 310 Papanui Road, Christchurch, 8052, New Zealand
| | - Kurt Joy
- Department of Biological Science, University of Waikato, Hamilton, New Zealand
- Orbica Ltd, 128 Litchfield St., Christchurch, 8011, New Zealand
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10
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Ramachandran D, Lindo Z, Meehan ML. Feeding rate and efficiency in an apex soil predator exposed to short-term temperature changes. Basic Appl Ecol 2021. [DOI: 10.1016/j.baae.2020.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Liu Q, Zhao Q, McMinn A, Yang EJ, Jiang Y. Planktonic microbial eukaryotes in polar surface waters: recent advances in high-throughput sequencing. MARINE LIFE SCIENCE & TECHNOLOGY 2021; 3:94-102. [PMID: 37073396 PMCID: PMC10064379 DOI: 10.1007/s42995-020-00062-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 07/22/2020] [Indexed: 05/03/2023]
Abstract
Marine microbial eukaryotes are important primary producers and play critical roles in key biogeochemical cycles. Recent advances in sequencing technology have focused attention on the extent of microbial biodiversity, revealing a huge, previously underestimated phylogenetic diversity with many new lineages. This technology has now become the most important tool to understand the ecological significance of this huge and novel diversity in polar oceans. In particular, high-throughput sequencing technologies have been successfully applied to enumerate and compare marine microbial diversity in polar environments. Here, a brief overview of polar microbial eukaryote diversity, as revealed by in-situ surveys of the high-throughput sequencing on 18S rRNA gene, is presented. Using these 'omic' approaches, further attention still needs to be focused on differences between specific locations and/or entire polar oceans and on bipolar comparisons of diversity and distribution.
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Affiliation(s)
- Qian Liu
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003 China
- Key Lab of Polar Oceanography and Global Ocean Change, Ocean University of China, Qingdao, 266003 China
| | - Qiannan Zhao
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003 China
- Key Lab of Polar Oceanography and Global Ocean Change, Ocean University of China, Qingdao, 266003 China
| | - Andrew McMinn
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003 China
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Eun Jin Yang
- Division of Polar Ocean Environment, Korea Polar Research Institute, 213-3 Songdo-dong, Yeonsu-gu, Incheon, 406-840 Korea
| | - Yong Jiang
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003 China
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003 China
- Key Lab of Polar Oceanography and Global Ocean Change, Ocean University of China, Qingdao, 266003 China
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Vegetation Abundance and Health Mapping Over Southwestern Antarctica Based on WorldView-2 Data and a Modified Spectral Mixture Analysis. REMOTE SENSING 2021. [DOI: 10.3390/rs13020166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In polar regions, vegetation is especially sensitive to climate dynamics and thus can be used as an indicator of the global and regional environmental change. However, in Antarctica, there is very little information on vegetation distribution and growth status. To fill this gap, we evaluated the ability of both linear and nonlinear spectral mixture analysis (SMA) models, including a group of newly developed modified Nascimento’s models for Antarctic vegetated areas (MNM-AVs), in estimating the abundance of major Antarctic vegetation types, i.e., mosses and lichens. The study was conducted using WorldView-2 satellite data and field measurements over the Fildes Peninsula and its surroundings, which are representative vegetated areas in Antarctica. In MNM-AVs, we introduced secondary scattering components for vegetation and its background to account for the sparsity of vegetation cover and reassigned their coefficients. The new models achieved improved performances, among which MNM-AV3 achieved the lowest error for mosses (lichens) abundance estimation with RMSE = 0.202 (0.213). Compared with MNM-AVs, the linear model performed particularly poor for lichens (RMSE = 0.322), which is in contrast to the case of mosses (RMSE = 0.212), demonstrating that spectral signals of lichens are more prone to mix with their backgrounds. Abundance maps of mosses and lichens, as well as a map of moss health status for the entire study area, were then obtained based on MNM-AV3 with around 80% overall accuracy. Moss areas account for 0.7695 km2 in Fildes and 0.3259 km2 in Ardley Island; unhealthy mosses amounted to 40% (49%) of the area in the summer of 2018 (2019), indicating considerable environmental stress.
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Ortiz M, Bosch J, Coclet C, Johnson J, Lebre P, Salawu-Rotimi A, Vikram S, Makhalanyane T, Cowan D. Microbial Nitrogen Cycling in Antarctic Soils. Microorganisms 2020; 8:E1442. [PMID: 32967081 PMCID: PMC7564152 DOI: 10.3390/microorganisms8091442] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 01/19/2023] Open
Abstract
The Antarctic continent is widely considered to be one of the most hostile biological habitats on Earth. Despite extreme environmental conditions, the ice-free areas of the continent, which constitute some 0.44% of the total continental land area, harbour substantial and diverse communities of macro-organisms and especially microorganisms, particularly in the more "hospitable" maritime regions. In the more extreme non-maritime regions, exemplified by the McMurdo Dry Valleys of South Victoria Land, nutrient cycling and ecosystem servicing processes in soils are largely driven by microbial communities. Nitrogen turnover is a cornerstone of ecosystem servicing. In Antarctic continental soils, specifically those lacking macrophytes, cold-active free-living diazotrophic microorganisms, particularly Cyanobacteria, are keystone taxa. The diazotrophs are complemented by heterotrophic bacterial and archaeal taxa which show the genetic capacity to perform elements of the entire N cycle, including nitrification processes such as the anammox reaction. Here, we review the current literature on nitrogen cycling genes, taxa, processes and rates from studies of Antarctic soils. In particular, we highlight the current gaps in our knowledge of the scale and contribution of these processes in south polar soils as critical data to underpin viable predictions of how such processes may alter under the impacts of future climate change.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Don Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria 0002, South Africa; (M.O.); (J.B.); (C.C.); (J.J.); (P.L.); (A.S.-R.); (S.V.); (T.M.)
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14
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Thompson AR, Geisen S, Adams BJ. Shotgun metagenomics reveal a diverse assemblage of protists in a model Antarctic soil ecosystem. Environ Microbiol 2020; 22:4620-4632. [PMID: 32803809 DOI: 10.1111/1462-2920.15198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 08/04/2020] [Accepted: 08/12/2020] [Indexed: 11/27/2022]
Abstract
The soils of the McMurdo Dry Valleys (MDV) of Antarctica are established models for understanding fundamental processes in soil ecosystem functioning (e.g. ecological tipping points, community structuring and nutrient cycling) because the extreme physical environment drastically reduces biodiversity and ecological complexity. Understanding the functioning of MDV soils requires in-depth knowledge of the diversity of MDV soil species. Protists, which contribute significantly to soil ecosystem functioning worldwide, remain poorly characterized in the MDV. To better assess the diversity of MDV protists, we performed shotgun metagenomics on 18 sites representing a variety of landscape features and edaphic variables. Our results show MDV soil protists are diverse at both the genus (155 of 281 eukaryote genera) and family (120) levels, but comprise only 6% of eukaryotic reads. Protists are structured by moisture, total N and distance from the local coast and possess limited richness in arid (< 5% moisture) and at high elevation sites, known drivers of communities in the MDV. High relative diversity and broad distribution of protists in our study promotes these organisms as key members of MDV soil microbiomes and the MDV as a useful system for understanding the contribution of soil protists to the structure of soil microbiomes.
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Affiliation(s)
| | - Stefan Geisen
- Department of Terrestrial Ecology, Netherlands Institute of Ecology, Wageningen, 6708 PB, The Netherlands.,Laboratory of Nematology, Wageningen University, Wageningen, 6700AA, The Netherlands
| | - Byron J Adams
- Department of Biology, Brigham Young University, Provo, UT, USA.,Monte L. Bean Life Science Museum, Brigham Young University, Provo, UT, USA
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15
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Convey P, Peck LS. Antarctic environmental change and biological responses. SCIENCE ADVANCES 2019; 5:eaaz0888. [PMID: 31807713 PMCID: PMC6881164 DOI: 10.1126/sciadv.aaz0888] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 11/04/2019] [Indexed: 05/22/2023]
Abstract
Antarctica and the surrounding Southern Ocean are facing complex environmental change. Their native biota has adapted to the region's extreme conditions over many millions of years. This unique biota is now challenged by environmental change and the direct impacts of human activity. The terrestrial biota is characterized by considerable physiological and ecological flexibility and is expected to show increases in productivity, population sizes and ranges of individual species, and community complexity. However, the establishment of non-native organisms in both terrestrial and marine ecosystems may present an even greater threat than climate change itself. In the marine environment, much more limited response flexibility means that even small levels of warming are threatening. Changing sea ice has large impacts on ecosystem processes, while ocean acidification and coastal freshening are expected to have major impacts.
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16
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Rego A, Raio F, Martins TP, Ribeiro H, Sousa AGG, Séneca J, Baptista MS, Lee CK, Cary SC, Ramos V, Carvalho MF, Leão PN, Magalhães C. Actinobacteria and Cyanobacteria Diversity in Terrestrial Antarctic Microenvironments Evaluated by Culture-Dependent and Independent Methods. Front Microbiol 2019; 10:1018. [PMID: 31214128 PMCID: PMC6555387 DOI: 10.3389/fmicb.2019.01018] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 04/24/2019] [Indexed: 12/13/2022] Open
Abstract
Bacterial diversity from McMurdo Dry Valleys in Antarctica, the coldest desert on earth, has become more easily assessed with the development of High Throughput Sequencing (HTS) techniques. However, some of the diversity remains inaccessible by the power of sequencing. In this study, we combine cultivation and HTS techniques to survey actinobacteria and cyanobacteria diversity along different soil and endolithic micro-environments of Victoria Valley in McMurdo Dry Valleys. Our results demonstrate that the Dry Valleys actinobacteria and cyanobacteria distribution is driven by environmental forces, in particular the effect of water availability and endolithic environments clearly conditioned the distribution of those communities. Data derived from HTS show that the percentage of cyanobacteria decreases from about 20% in the sample closest to the water source to negligible values on the last three samples of the transect with less water availability. Inversely, actinobacteria relative abundance increases from about 20% in wet soils to over 50% in the driest samples. Over 30% of the total HTS data set was composed of actinobacterial strains, mainly distributed by 5 families: Sporichthyaceae, Euzebyaceae, Patulibacteraceae, Nocardioidaceae, and Rubrobacteraceae. However, the 11 actinobacterial strains isolated in this study, belonged to Micrococcaceae and Dermacoccaceae families that were underrepresented in the HTS data set. A total of 10 cyanobacterial strains from the order Synechococcales were also isolated, distributed by 4 different genera (Nodosilinea, Leptolyngbya, Pectolyngbya, and Acaryochloris-like). In agreement with the cultivation results, Leptolyngbya was identified as dominant genus in the HTS data set. Acaryochloris-like cyanobacteria were found exclusively in the endolithic sample and represented 44% of the total 16S rRNA sequences, although despite our efforts we were not able to properly isolate any strain from this Acaryochloris-related group. The importance of combining cultivation and sequencing techniques is highlighted, as we have shown that culture-dependent methods employed in this study were able to retrieve actinobacteria and cyanobacteria taxa that were not detected in HTS data set, suggesting that the combination of both strategies can be usefull to recover both abundant and rare members of the communities.
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Affiliation(s)
- Adriana Rego
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Francisco Raio
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Teresa P Martins
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Hugo Ribeiro
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - António G G Sousa
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Joana Séneca
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Mafalda S Baptista
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton, New Zealand
| | - Charles K Lee
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton, New Zealand.,School of Science, University of Waikato, Hamilton, New Zealand
| | - S Craig Cary
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton, New Zealand.,School of Science, University of Waikato, Hamilton, New Zealand
| | - Vitor Ramos
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Maria F Carvalho
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Pedro N Leão
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal
| | - Catarina Magalhães
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Porto, Portugal.,Faculty of Sciences, University of Porto, Porto, Portugal
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17
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Li W, Morgan-Kiss RM. Influence of Environmental Drivers and Potential Interactions on the Distribution of Microbial Communities From Three Permanently Stratified Antarctic Lakes. Front Microbiol 2019; 10:1067. [PMID: 31156585 PMCID: PMC6530420 DOI: 10.3389/fmicb.2019.01067] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 04/29/2019] [Indexed: 12/14/2022] Open
Abstract
The McMurdo Dry Valley (MDV) lakes represent unique habitats in the microbial world. Perennial ice covers protect liquid water columns from either significant allochthonous inputs or seasonal mixing, resulting in centuries of stable biogeochemistry. Extreme environmental conditions including low seasonal photosynthetically active radiation (PAR), near freezing temperatures, and oligotrophy have precluded higher trophic levels from the food webs. Despite these limitations, diverse microbial life flourishes in the stratified water columns, including Archaea, bacteria, fungi, protists, and viruses. While a few recent studies have applied next generation sequencing, a thorough understanding of the MDV lake microbial diversity and community structure is currently lacking. Here we used Illumina MiSeq sequencing of the 16S and 18S rRNA genes combined with a microscopic survey of key eukaryotes to compare the community structure and potential interactions among the bacterial and eukaryal communities within the water columns of Lakes Bonney (east and west lobes, ELB, and WLB, respectively) and Fryxell (FRX). Communities were distinct between the upper, oxic layers and the dark, anoxic waters, particularly among the bacterial communities residing in WLB and FRX. Both eukaryal and bacterial community structure was influenced by different biogeochemical parameters in the oxic and anoxic zones. Bacteria formed complex interaction networks which were lake-specific. Several eukaryotes exhibit potential interactions with bacteria in ELB and WLB, while interactions between these groups in the more productive FRX were relatively rare.
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Affiliation(s)
- Wei Li
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, United States
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18
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Recession and Ice Surface Elevation Changes of Baranowski Glacier and Its Impact on Proglacial Relief (King George Island, West Antarctica). GEOSCIENCES 2018. [DOI: 10.3390/geosciences8100355] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Glacial forefields areas are dynamic landscapes, and due to the glacier frontal position changes, they are sensitive to climatic fluctuations. The results of the analysis of aerial photos, satellite imagery, archival maps, and terrestrial laser scanning surveys are presented. These investigations reveal that the ice surface decreased during the period 1989–2001, when almost the entire current forefield was already uncovered. Moreover, it is shown that, since 1969, there has been a relationship between the changes in air temperature and the changes of the annual front position rate of Baranowski Glacier. Specifically, the results demonstrate that during the cooling observed for the Antarctic Peninsula Regions since 2000, there is a deceleration of the recession rate and ice surface elevation changes of Baranowski Glacier. It is also shown that the fluctuation of the areal extent of the glacier as well as ice surface elevation changes are closely associated with proglacial relief. Moreover, it is shown that the difference in the retreat of the northern and southern tongue of the glacier can be explained by the presence of relatively warm water in the shallow bay, which can enhance the melting process of the northern part. In addition, existence of long flutes and crevasse fill ridges on the analyzed forefield of Baranowski Glacier suggest that the former episodes of its surge, which could happen at least in the northern part of the forefield and middle part of the southern forefield of the glacier.
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19
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Grain Size Distribution of Bedload Transport in a Glaciated Catchment (Baranowski Glacier, King George Island, Western Antarctica). WATER 2018. [DOI: 10.3390/w10040360] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Drivers of solar radiation variability in the McMurdo Dry Valleys, Antarctica. Sci Rep 2018; 8:5002. [PMID: 29568040 PMCID: PMC5864877 DOI: 10.1038/s41598-018-23390-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 03/05/2018] [Indexed: 11/08/2022] Open
Abstract
Annually averaged solar radiation in the McMurdo Dry Valleys, Antarctica has varied by over 20 W m-2 during the past three decades; however, the drivers of this variability are unknown. Because small differences in radiation are important to water availability and ecosystem functioning in polar deserts, determining the causes are important to predictions of future desert processes. We examine the potential drivers of solar variability and systematically eliminate all but stratospheric sulfur dioxide. We argue that increases in stratospheric sulfur dioxide increase stratospheric aerosol optical depth and decrease solar intensity. Because of the polar location of the McMurdo Dry Valleys (77-78°S) and relatively long solar ray path through the stratosphere, terrestrial solar intensity is sensitive to small differences in stratospheric transmissivity. Important sources of sulfur dioxide include natural (wildfires and volcanic eruptions) and anthropogenic emission.
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21
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Kwon E, English WB, Weiser EL, Franks SE, Hodkinson DJ, Lank DB, Sandercock BK. Delayed egg-laying and shortened incubation duration of Arctic-breeding shorebirds coincide with climate cooling. Ecol Evol 2017; 8:1339-1351. [PMID: 29375802 PMCID: PMC5773331 DOI: 10.1002/ece3.3733] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 11/14/2017] [Indexed: 01/21/2023] Open
Abstract
Biological impacts of climate change are exemplified by shifts in phenology. As the timing of breeding advances, the within‐season relationships between timing of breeding and reproductive traits may change and cause long‐term changes in the population mean value of reproductive traits. We investigated long‐term changes in the timing of breeding and within‐season patterns of clutch size, egg volume, incubation duration, and daily nest survival of three shorebird species between two decades. Based on previously known within‐season patterns and assuming a warming trend, we hypothesized that the timing of clutch initiation would advance between decades and would be coupled with increases in mean clutch size, egg volume, and daily nest survival rate. We monitored 1,378 nests of western sandpipers, semipalmated sandpipers, and red‐necked phalaropes at a subarctic site during 1993–1996 and 2010–2014. Sandpipers have biparental incubation, whereas phalaropes have uniparental incubation. We found an unexpected long‐term cooling trend during the early part of the breeding season. Three species delayed clutch initiation by 5 days in the 2010s relative to the 1990s. Clutch size and daily nest survival showed strong within‐season declines in sandpipers, but not in phalaropes. Egg volume showed strong within‐season declines in one species of sandpiper, but increased in phalaropes. Despite the within‐season patterns in traits and shifts in phenology, clutch size, egg volume, and daily nest survival were similar between decades. In contrast, incubation duration did not show within‐season variation, but decreased by 2 days in sandpipers and increased by 2 days in phalaropes. Shorebirds demonstrated variable breeding phenology and incubation duration in relation to climate cooling, but little change in nonphenological components of traits. Our results indicate that the breeding phenology of shorebirds is closely associated with the temperature conditions on breeding ground, the effects of which can vary among reproductive traits and among sympatric species.
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Affiliation(s)
- Eunbi Kwon
- Division of BiologyKansas State UniversityManhattanKSUSA
- Present address:
Department of Fish and Wildlife ConservationVirginia TechBlacksburgVAUSA
| | - Willow B. English
- Department of Biological SciencesSimon Fraser UniversityBurnabyBCCanada
- Present address:
Department of BiologyCarleton UniversityOttawaONCanada
| | - Emily L. Weiser
- Division of BiologyKansas State UniversityManhattanKSUSA
- Present address:
U.S. Geological SurveyUpper Midwest Environmental Sciences CenterLa CrosseWIUSA
| | | | | | - David B. Lank
- Department of Biological SciencesSimon Fraser UniversityBurnabyBCCanada
| | - Brett K. Sandercock
- Division of BiologyKansas State UniversityManhattanKSUSA
- Present address:
Norwegian Institute for Nature ResearchTrondheimNorway
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22
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23
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Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica. Nat Ecol Evol 2017; 1:1334-1338. [PMID: 29046542 DOI: 10.1038/s41559-017-0253-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/26/2017] [Indexed: 11/08/2022]
Abstract
Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes. Multi-decadal records indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift. A decadal summer cooling phase ended in 2002 with intense glacial melt ('flood year')-a step-change in water availability triggering distinct changes in the ecosystem. Before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, decreasing primary production in lakes and streams, and diminishing soil secondary production. Since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow. Biological responses varied; one stream cyanobacterial mat type immediately increased production, but another stream mat type, soil invertebrates and lake primary productivity responded asynchronously a few years after 2002. This ecosystem response to a climatic anomaly demonstrates differential biological community responses to substantial perturbations, and the mediation of biological responses to climate change by changes in physical ecosystem properties.
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24
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Alpine soil carbon is vulnerable to rapid microbial decomposition under climate cooling. ISME JOURNAL 2017; 11:2102-2111. [PMID: 28534876 DOI: 10.1038/ismej.2017.75] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 03/14/2017] [Accepted: 03/23/2017] [Indexed: 11/08/2022]
Abstract
As climate cooling is increasingly regarded as important natural variability of long-term global warming trends, there is a resurging interest in understanding its impact on biodiversity and ecosystem functioning. Here, we report a soil transplant experiment from lower to higher elevations in a Tibetan alpine grassland to simulate the impact of cooling on ecosystem community structure and function. Three years of cooling resulted in reduced plant productivity and microbial functional potential (for example, carbon respiration and nutrient cycling). Microbial genetic markers associated with chemically recalcitrant carbon decomposition remained unchanged despite a decrease in genes associated with chemically labile carbon decomposition. As a consequence, cooling-associated changes correlated with a decrease in soil organic carbon (SOC). Extrapolation of these results suggests that for every 1 °C decrease in annual average air temperature, 0.1 Pg (0.3%) of SOC would be lost from the Tibetan plateau. These results demonstrate that microbial feedbacks to cooling have the potential to differentially impact chemically labile and recalcitrant carbon turnover, which could lead to strong, adverse consequences on soil C storage. Our findings are alarming, considering the frequency of short-term cooling and its scale to disrupt ecosystems and biogeochemical cycling.
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25
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Slattery M, Lesser MP. Allelopathy-mediated competition in microbial mats from Antarctic lakes. FEMS Microbiol Ecol 2017; 93:3003319. [PMID: 28334326 DOI: 10.1093/femsec/fix019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/15/2017] [Indexed: 11/14/2022] Open
Abstract
Microbial mats are vertically stratified communities that host a complex consortium of microorganisms, dominated by cyanobacteria, which compete for available nutrients and environmental niches, within these extreme habitats. The Antarctic Dry Valleys near McMurdo Sound include a series of lakes within the drainage basin that are bisected by glacial traverses. These lakes are traditionally independent, but recent increases in glacial melting have allowed two lakes (Chad and Hoare) to become connected by a meltwater stream. Microbial mats were collected from these lakes, and cultured under identical conditions at the McMurdo Station laboratory. Replicate pairings of the microbial mats exhibited consistent patterns of growth inhibition indicative of competitive dominance. Natural products were extracted from the microbial mats, and a disk diffusion assay was utilized to show that allelochemical compounds mediate competitive interactions. Both microscopy and 16S rRNA sequencing show that these mats contain significant populations of cyanobacteria known to produce allelochemicals. Two compounds were isolated from these microbial mats that might be important in the chemical ecology of these psychrophiles. In other disk:mat pairings, including extract versus mat of origin, the allelochemicals exhibited no effect. Taken together, these results indicate that Antarctic lake microbial mats can compete via allelopathy.
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Affiliation(s)
- Marc Slattery
- Department of BioMolecular Sciences, University of Mississippi, Oxford, MS 38677, USA
| | - Michael P Lesser
- School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, NH 03824, USA
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26
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Wei STS, Lacap-Bugler DC, Lau MCY, Caruso T, Rao S, de Los Rios A, Archer SK, Chiu JMY, Higgins C, Van Nostrand JD, Zhou J, Hopkins DW, Pointing SB. Taxonomic and Functional Diversity of Soil and Hypolithic Microbial Communities in Miers Valley, McMurdo Dry Valleys, Antarctica. Front Microbiol 2016; 7:1642. [PMID: 27812351 PMCID: PMC5071352 DOI: 10.3389/fmicb.2016.01642] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Accepted: 10/03/2016] [Indexed: 12/04/2022] Open
Abstract
The McMurdo Dry Valleys of Antarctica are an extreme polar desert. Mineral soils support subsurface microbial communities and translucent rocks support development of hypolithic communities on ventral surfaces in soil contact. Despite significant research attention, relatively little is known about taxonomic and functional diversity or their inter-relationships. Here we report a combined diversity and functional interrogation for soil and hypoliths of the Miers Valley in the McMurdo Dry Valleys of Antarctica. The study employed 16S rRNA fingerprinting and high throughput sequencing combined with the GeoChip functional microarray. The soil community was revealed as a highly diverse reservoir of bacterial diversity dominated by actinobacteria. Hypolithic communities were less diverse and dominated by cyanobacteria. Major differences in putative functionality were that soil communities displayed greater diversity in stress tolerance and recalcitrant substrate utilization pathways, whilst hypolithic communities supported greater diversity of nutrient limitation adaptation pathways. A relatively high level of functional redundancy in both soil and hypoliths may indicate adaptation of these communities to fluctuating environmental conditions.
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Affiliation(s)
- Sean T S Wei
- Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology Auckland, New Zealand
| | - Donnabella C Lacap-Bugler
- Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology Auckland, New Zealand
| | - Maggie C Y Lau
- Department of Geosciences, Princeton University Princeton, NJ, USA
| | - Tancredi Caruso
- School of Biological Sciences, Queen's University Belfast Belfast, Northern Ireland
| | - Subramanya Rao
- Department of Health Technology and Informatics, Hong Kong Polytechnic University Hong Kong, China
| | - Asunción de Los Rios
- Departamento de Biogeoquímica y Ecología Microbiana, Museo Nacional de Ciencias Naturales Madrid, Spain
| | - Stephen K Archer
- Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology Auckland, New Zealand
| | - Jill M Y Chiu
- Department of Biology, Hong Kong Baptist University Hong Kong, China
| | - Colleen Higgins
- Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of Technology Auckland, New Zealand
| | - Joy D Van Nostrand
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of Oklahoma Norman, OK, USA
| | - Jizhong Zhou
- Department of Microbiology and Plant Biology, Institute for Environmental Genomics, University of OklahomaNorman, OK, USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua UniversityBeijing, China; Earth Sciences Division, Lawrence Berkeley National LaboratoryBerkeley, CA, USA
| | - David W Hopkins
- School of Agriculture, Food and Environment, The Royal Agricultural University Gloucestershire, UK
| | - Stephen B Pointing
- Institute for Applied Ecology New Zealand, School of Applied Sciences, Auckland University of TechnologyAuckland, New Zealand; Institute of Nature and Environmental Technology, Kanazawa UniversityKanazawa, Japan
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27
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Fountain AG, Saba G, Adams B, Doran P, Fraser W, Gooseff M, Obryk M, Priscu JC, Stammerjohn S, Virginia RA. The Impact of a Large-Scale Climate Event on Antarctic Ecosystem Processes. Bioscience 2016. [DOI: 10.1093/biosci/biw110] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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28
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Bowman JS, Vick-Majors TJ, Morgan-Kiss R, Takacs-Vesbach C, Ducklow HW, Priscu JC. Microbial Community Dynamics in Two Polar Extremes: The Lakes of the McMurdo Dry Valleys and the West Antarctic Peninsula Marine Ecosystem. Bioscience 2016. [DOI: 10.1093/biosci/biw103] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Obryk MK, Doran PT, Friedlaender AS, Gooseff MN, Li W, Morgan-Kiss RM, Priscu JC, Schofield O, Stammerjohn SE, Steinberg DK, Ducklow HW. Responses of Antarctic Marine and Freshwater Ecosystems to Changing Ice Conditions. Bioscience 2016. [DOI: 10.1093/biosci/biw109] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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30
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Evidence for dispersal and habitat controls on pond diatom communities from the McMurdo Sound Region of Antarctica. Polar Biol 2016. [DOI: 10.1007/s00300-016-1901-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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31
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Musilova M, Wright G, Ward JM, Dartnell LR. Isolation of Radiation-Resistant Bacteria from Mars Analog Antarctic Dry Valleys by Preselection, and the Correlation between Radiation and Desiccation Resistance. ASTROBIOLOGY 2015; 15:1076-1090. [PMID: 26684506 PMCID: PMC4683558 DOI: 10.1089/ast.2014.1278] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 10/08/2015] [Indexed: 05/31/2023]
Abstract
UNLABELLED Extreme radiation-resistant microorganisms can survive doses of ionizing radiation far greater than are present in the natural environment. Radiation resistance is believed to be an incidental adaptation to desiccation resistance, as both hazards cause similar cellular damage. Desert soils are, therefore, promising targets to prospect for new radiation-resistant strains. This is the first study to isolate radiation-resistant microbes by using gamma-ray exposure preselection from the extreme cold desert of the Antarctic Dry Valleys (a martian surface analogue). Halomonads, identified by 16S rRNA gene sequencing, were the most numerous survivors of the highest irradiation exposures. They were studied here for the first time for both their desiccation and irradiation survival characteristics. In addition, the association between desiccation and radiation resistance has not been investigated quantitatively before for a broad diversity of microorganisms. Thus, a meta-analysis of scientific literature was conducted to gather a larger data set. A strong correlation was found between desiccation and radiation resistance, indicating that an increase in the desiccation resistance of 5 days corresponds to an increase in the room-temperature irradiation survival of 1 kGy. Irradiation at -79°C (representative of average martian surface temperatures) increases the microbial radiation resistance 9-fold. Consequently, the survival of the cold-, desiccation-, and radiation-resistant organisms isolated here has implications for the potential habitability of dormant or cryopreserved life on Mars. KEY WORDS Extremophiles-Halomonas sp.-Antarctica-Mars-Ionizing radiation-Cosmic rays.
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Affiliation(s)
| | - Gary Wright
- Department of Engineering and Applied Science, Cranfield University, Shrivenham, Swindon, UK
| | - John M. Ward
- Department of Biochemical Engineering, University College London, London, UK
| | - Lewis R. Dartnell
- UCL Institute for Origins, University College London, London, UK
- The Centre for Planetary Sciences at UCL/Birkbeck, Earth Sciences, University College London, London, UK
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32
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Impact of diurnal freeze–thaw cycles on the soil nematode Scottnema lindsayae in Taylor Valley, Antarctica. Polar Biol 2015. [DOI: 10.1007/s00300-015-1809-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Life in the Main Channel: Long-Term Hydrologic Control of Microbial Mat Abundance in McMurdo Dry Valley Streams, Antarctica. Ecosystems 2014. [DOI: 10.1007/s10021-014-9829-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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34
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Bishop JL, Englert PAJ, Patel S, Tirsch D, Roy AJ, Koeberl C, Böttger U, Hanke F, Jaumann R. Mineralogical analyses of surface sediments in the Antarctic Dry Valleys: coordinated analyses of Raman spectra, reflectance spectra and elemental abundances. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:rsta.2014.0198. [PMID: 25368345 DOI: 10.1098/rsta.2014.0198] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Surface sediments at Lakes Fryxell, Vanda and Brownworth in the Antarctic Dry Valleys (ADV) were investigated as analogues for the cold, dry environment on Mars. Sediments were sampled from regions surrounding the lakes and from the ice cover on top of the lakes. The ADV sediments were studied using Raman spectra of individual grains and reflectance spectra of bulk particulate samples and compared with previous analyses of subsurface and lakebottom sediments. Elemental abundances were coordinated with the spectral data in order to assess trends in sediment alteration. The surface sediments in this study were compared with lakebottom sediments (Bishop JL et al. 2003 Int. J. Astrobiol. 2, 273-287 (doi:10.1017/S1473550403001654)) and samples from soil pits (Englert P et al. 2013 In European Planetary Science Congress, abstract no. 96; Englert P et al. 2014 In 45th Lunar and Planetary Science Conf., abstract no. 1707). Feldspar, quartz and pyroxene are common minerals found in all the sediments. Minor abundances of carbonate, chlorite, actinolite and allophane are also found in the surface sediments, and are similar to minerals found in greater abundance in the lakebottom sediments. Surface sediment formation is dominated by physical processes; a few centimetres below the surface chemical alteration sets in, whereas lakebottom sediments experience biomineralization. Characterizing the mineralogical variations in these samples provides insights into the alteration processes occurring in the ADV and supports understanding alteration in the cold and dry environment on Mars.
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Affiliation(s)
- Janice L Bishop
- Carl Sagan Center, SETI Institute, 189 Bernardo Avenue, Mountain View, CA, USA NASA Ames Research Center, Moffett Field, CA, USA
| | - Peter A J Englert
- Hawaii Institute of Geophysics and Planetology, University of Hawaii at Mânoa, HI, USA
| | - Shital Patel
- Carl Sagan Center, SETI Institute, 189 Bernardo Avenue, Mountain View, CA, USA Department of Chemistry, San Jose State University, San Jose, CA, USA
| | | | - Alex J Roy
- Department of Land and Natural Resources, Honolulu, HI, USA
| | - Christian Koeberl
- Department of Lithospheric Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria Natural History Museum, Burgring 7, 1010 Vienna, Austria
| | - Ute Böttger
- German Aerospace Center (DLR), Berlin, Germany
| | - Franziska Hanke
- German Aerospace Center (DLR), Berlin, Germany Technische Universität Berlin, Berlin, Germany
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Dreesens LL, Lee CK, Cary SC. The Distribution and Identity of Edaphic Fungi in the McMurdo Dry Valleys. BIOLOGY 2014; 3:466-83. [PMID: 25079129 PMCID: PMC4192622 DOI: 10.3390/biology3030466] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/14/2014] [Accepted: 07/16/2014] [Indexed: 11/30/2022]
Abstract
Contrary to earlier assumptions, molecular evidence has demonstrated the presence of diverse and localized soil bacterial communities in the McMurdo Dry Valleys of Antarctica. Meanwhile, it remains unclear whether fungal signals so far detected in Dry Valley soils using both culture-based and molecular techniques represent adapted and ecologically active biomass or spores transported by wind. Through a systematic and quantitative molecular survey, we identified significant heterogeneities in soil fungal communities across the Dry Valleys that robustly correlate with heterogeneities in soil physicochemical properties. Community fingerprinting analysis and 454 pyrosequencing of the fungal ribosomal intergenic spacer region revealed different levels of heterogeneity in fungal diversity within individual Dry Valleys and a surprising abundance of Chytridiomycota species, whereas previous studies suggested that Dry Valley soils were dominated by Ascomycota and Basidiomycota. Critically, we identified significant differences in fungal community composition and structure of adjacent sites with no obvious barrier to aeolian transport between them. These findings suggest that edaphic fungi of the Antarctic Dry Valleys are adapted to local environments and represent an ecologically relevant (and possibly important) heterotrophic component of the ecosystem.
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Affiliation(s)
- Lisa L Dreesens
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton 3216, New Zealand.
| | - Charles K Lee
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton 3216, New Zealand.
| | - S Craig Cary
- International Centre for Terrestrial Antarctic Research, University of Waikato, Hamilton 3216, New Zealand.
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36
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Li Y, Kromer B, Schukraft G, Bubenzer O, Huang MR, Wang ZM, Bian LG, Li CS. Growth rate of Usnea aurantiacoatra (Jacq.) Bory on Fildes Peninsula, Antarctica and its climatic background. PLoS One 2014; 9:e100735. [PMID: 24968131 PMCID: PMC4072682 DOI: 10.1371/journal.pone.0100735] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/30/2014] [Indexed: 11/21/2022] Open
Abstract
The ages of a fruticose lichen of Usnea aurantiacoatra (Jacq.) Bory, from Fildes Peninsula, King George Island, Southwest Antarctic, were determined by radiocarbon (14C), and it is 1993–1996 at bottom and 2006–2007 at top of the lichen branch. The growth rates of U. aurantiacoatra calculated are 4.3 to 5.5 mm year−1 based on its length and ages. The comparisons show that the growth rates of U. aurantiacoatra are higher than those of U. antarctica (0.4 to 1.1 mm year−1). The growth rates of fruticose lichens are always higher, usually >2 mm year−1, than those of crustose ones, usually <1 mm year−1, in polar areas. A warming trend on Fildes Peninsula is recorded in the period from 1969 to 2010 obviously: the mean annual temperature rose from −2.75 to −1.9°C and the average temperature of summer months from 0.95 to 1.4°C, as well as the average temperature of winter months from −6.75 to −5.5°C. The alteration of lichen growth rates in polar areas may respond to the climatic and environmental changes, and the lichens may act as bio-monitor of natural condition.
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Affiliation(s)
- Ying Li
- Institute of Botany, Beijing, China
- Heidelberg University, Heidelberg, Germany
| | - Bernd Kromer
- Klaus-Tschira-Labor (Curt-Engelhorn-Zentrum Archäometrie gGmbH), Mannheim, Germany
| | | | | | | | | | - Lin-Gen Bian
- Chinese Academy of Meteorological Sciences, Beijing, China
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Adams BJ, Wall DH, Virginia RA, Broos E, Knox MA. Ecological biogeography of the terrestrial nematodes of victoria land, antarctica. Zookeys 2014:29-71. [PMID: 25061360 PMCID: PMC4109451 DOI: 10.3897/zookeys.419.7180] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 04/10/2014] [Indexed: 11/12/2022] Open
Abstract
The terrestrial ecosystems of Victoria Land, Antarctica are characteristically simple in terms of biological diversity and ecological functioning. Nematodes are the most commonly encountered and abundant metazoans of Victoria Land soils, yet little is known of their diversity and distribution. Herein we present a summary of the geographic distribution, habitats and ecology of the terrestrial nematodes of Victoria Land from published and unpublished sources. All Victoria Land nematodes are endemic to Antarctica, and many are common and widely distributed at landscape scales. However, at smaller spatial scales, populations can have patchy distributions, with the presence or absence of each species strongly influenced by specific habitat requirements. As the frequency of nematode introductions to Antarctica increases, and soil habitats are altered in response to climate change, our current understanding of the environmental parameters associated with the biogeography of Antarctic nematofauna will be crucial to monitoring and possibly mitigating changes to these unique soil ecosystems.
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Affiliation(s)
- Byron J Adams
- Department of Biology, and Evolutionary Ecology Laboratories, Brigham Young University, Provo, UT 84602
| | - Diana H Wall
- Department of Biology and Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499
| | - Ross A Virginia
- Environmental Studies Program, Dartmouth College, Hanover, NH 03755
| | - Emma Broos
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499
| | - Matthew A Knox
- Department of Biology and Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499
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Convey P, Chown SL, Clarke A, Barnes DKA, Bokhorst S, Cummings V, Ducklow HW, Frati F, Green TGA, Gordon S, Griffiths HJ, Howard-Williams C, Huiskes AHL, Laybourn-Parry J, Lyons WB, McMinn A, Morley SA, Peck LS, Quesada A, Robinson SA, Schiaparelli S, Wall DH. The spatial structure of Antarctic biodiversity. ECOL MONOGR 2014. [DOI: 10.1890/12-2216.1] [Citation(s) in RCA: 232] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Richter I, Herbold CW, Lee CK, McDonald IR, Barrett JE, Cary SC. Influence of soil properties on archaeal diversity and distribution in the McMurdo Dry Valleys, Antarctica. FEMS Microbiol Ecol 2014; 89:347-59. [PMID: 24646164 DOI: 10.1111/1574-6941.12322] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/27/2014] [Accepted: 03/05/2014] [Indexed: 11/29/2022] Open
Abstract
Archaea are the least understood members of the microbial community in Antarctic mineral soils. Although their occurrence in Antarctic coastal soils has been previously documented, little is known about their distribution in soils across the McMurdo Dry Valleys, Victoria Land. In this study, terminal-restriction fragment length polymorphism (t-RFLP) analysis and 454 pyrosequencing were coupled with a detailed analysis of soil physicochemical properties to characterize archaeal diversity and identify environmental factors that might shape and maintain archaeal communities in soils of the three southern most McMurdo Dry Valleys (Garwood, Marshall, and Miers Valley). Archaea were successfully detected in all inland and coastal mineral soils tested, revealing a low overall richness (mean of six operational taxonomic units [OTUs] per sample site). However, OTU richness was higher in some soils and this higher richness was positively correlated with soil water content, indicating water as a main driver of archaeal community richness. In total, 18 archaeal OTUs were detected, predominately Thaumarchaeota affiliated with Marine Group 1.1b (> 80% of all archaeal sequences recovered). Less abundant OTUs (2% of all archaeal sequences) were loosely related to members of the phylum Euryarchaeota. This is the first comprehensive study showing a widespread presence and distribution of Archaea in inland Antarctic soils.
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Affiliation(s)
- Ingrid Richter
- School of Science, University of Waikato, Hamilton, New Zealand
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40
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Accelerated thermokarst formation in the McMurdo Dry Valleys, Antarctica. Sci Rep 2014; 3:2269. [PMID: 23881292 PMCID: PMC3721085 DOI: 10.1038/srep02269] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/01/2013] [Indexed: 11/08/2022] Open
Abstract
Thermokarst is a land surface lowered and disrupted by melting ground ice. Thermokarst is a major driver of landscape change in the Arctic, but has been considered to be a minor process in Antarctica. Here, we use ground-based and airborne LiDAR coupled with timelapse imaging and meteorological data to show that 1) thermokarst formation has accelerated in Garwood Valley, Antarctica; 2) the rate of thermokarst erosion is presently ~ 10 times the average Holocene rate; and 3) the increased rate of thermokarst formation is driven most strongly by increasing insolation and sediment/albedo feedbacks. This suggests that sediment enhancement of insolation-driven melting may act similarly to expected increases in Antarctic air temperature (presently occurring along the Antarctic Peninsula), and may serve as a leading indicator of imminent landscape change in Antarctica that will generate thermokarst landforms similar to those in Arctic periglacial terrains.
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41
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Bramley-Alves J, King DH, Robinson SA, Miller RE. Dominating the Antarctic Environment: Bryophytes in a Time of Change. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-007-6988-5_17] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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42
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43
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Quayle WC, Convey P, Peck LS, Ellis-Evans CJ, Butler HG, Peat HJ. Ecological Responses of Maritime Antarctic Lakes to Regional Climate Change. ANTARCTIC PENINSULA CLIMATE VARIABILITY: HISTORICAL AND PALEOENVIRONMENTAL PERSPECTIVES 2013. [DOI: 10.1029/ar079p0159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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44
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Response of Wintertime Antarctic Temperatures to the Antarctic Oscillation: Results of a Regional Climate Model. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/ar079p0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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45
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Nielsen UN, Wall DH. The future of soil invertebrate communities in polar regions: different climate change responses in the Arctic and Antarctic? Ecol Lett 2013; 16:409-19. [DOI: 10.1111/ele.12058] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 09/13/2012] [Accepted: 11/26/2012] [Indexed: 11/28/2022]
Affiliation(s)
| | - Diana H. Wall
- Natural Resource Ecology Laboratory and Department of Biology; Colorado State University; Fort Collins; CO; 80523; USA
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46
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Warnock JP, Doran PT. Distribution of Siliceous-Walled Algae in Taylor Valley, Antarctica Lakes. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ijg.2013.44064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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47
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Screen JA, Simmonds I. Half-century air temperature change above Antarctica: Observed trends and spatial reconstructions. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017885] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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48
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Meiring TL, Tuffin IM, Cary C, Cowan DA. Genome sequence of temperate bacteriophage Psymv2 from Antarctic Dry Valley soil isolate Psychrobacter sp. MV2. Extremophiles 2012; 16:715-26. [PMID: 22760730 DOI: 10.1007/s00792-012-0467-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 06/14/2012] [Indexed: 11/24/2022]
Abstract
A temperate phage, Psymv2, was isolated from an Antarctic soil bacterium, Psychrobacter sp. MV2. The morphology of Psymv2 was typical of the Siphoviridae, with an isometric head and non-contractile tail. The Psymv2 genome was found to be 35,725 bp in length, had a G + C content of 44.5 %, with 49 protein-coding genes and one tRNA gene predicted. Integration of Psymv2 occurred at an ssrA gene, with the last 27 bases of this gene directly repeated at the prophage ends. The genome was organised in a modular fashion: integration, regulation, packaging, head assembly, tail assembly, host specificity and lysis. While the genome sequence had little similarity on a nucleotide level to previously reported phage sequences, the genome architecture resembled that of Siphoviridae of low G + C Gram-positive bacteria. The closest relatives to Psymv2 were uncharacterized putative prophages within the P. arcticus 273-4 and Acinetobacter baumannii 6013113 genomes. Global alignment of the Psymv2 genome and these prophages revealed significant conservation of the structural modules despite the large spatial divergence of their hosts. A number of unique ORFs were identified in the Psymv2 genome that may contribute to phage and lysogen fitness.
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Affiliation(s)
- Tracy L Meiring
- Institute for Microbial Biotechnology and Metagenomics, University of the Western Cape, Office 2117, Level 2 Life Sciences Building, Modderdam Rd, Bellville 7535, South Africa
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49
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Bohuslavová O, Šmilauer P, Elster J. Usnea lichen community biomass estimation on volcanic mesas, James Ross Island, Antarctica. Polar Biol 2012. [DOI: 10.1007/s00300-012-1197-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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50
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Jungblut AD, Wood SA, Hawes I, Webster-Brown J, Harris C. The Pyramid Trough Wetland: environmental and biological diversity in a newly created Antarctic protected area. FEMS Microbiol Ecol 2012; 82:356-66. [DOI: 10.1111/j.1574-6941.2012.01380.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 03/02/2012] [Accepted: 03/30/2012] [Indexed: 11/27/2022] Open
Affiliation(s)
| | | | - Ian Hawes
- Waterways Centre for Freshwater Management and Gateway Antarctica; University of Canterbury; Christchurch; New Zealand
| | - Jenny Webster-Brown
- Waterways Centre for Freshwater Management; University of Canterbury & Lincoln; Christchurch; New Zealand
| | - Colin Harris
- Environmental Research and Assessment; Cambridge; UK
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