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Lee JR, Waterman MJ, Shaw JD, Bergstrom DM, Lynch HJ, Wall DH, Robinson SA. Islands in the ice: Potential impacts of habitat transformation on Antarctic biodiversity. GLOBAL CHANGE BIOLOGY 2022; 28:5865-5880. [PMID: 35795907 PMCID: PMC9542894 DOI: 10.1111/gcb.16331] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/15/2022] [Indexed: 05/04/2023]
Abstract
Antarctic biodiversity faces an unknown future with a changing climate. Most terrestrial biota is restricted to limited patches of ice-free land in a sea of ice, where they are adapted to the continent's extreme cold and wind and exploit microhabitats of suitable conditions. As temperatures rise, ice-free areas are predicted to expand, more rapidly in some areas than others. There is high uncertainty as to how species' distributions, physiology, abundance, and survivorship will be affected as their habitats transform. Here we use current knowledge to propose hypotheses that ice-free area expansion (i) will increase habitat availability, though the quality of habitat will vary; (ii) will increase structural connectivity, although not necessarily increase opportunities for species establishment; (iii) combined with milder climates will increase likelihood of non-native species establishment, but may also lengthen activity windows for all species; and (iv) will benefit some species and not others, possibly resulting in increased homogeneity of biodiversity. We anticipate considerable spatial, temporal, and taxonomic variation in species responses, and a heightened need for interdisciplinary research to understand the factors associated with ecosystem resilience under future scenarios. Such research will help identify at-risk species or vulnerable localities and is crucial for informing environmental management and policymaking into the future.
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Affiliation(s)
- Jasmine R. Lee
- British Antarctic SurveyNERCCambridgeUK
- Securing Antarctica's Environmental Future, School of Biology and Environmental ScienceQueensland University of TechnologyBrisbaneQLDAustralia
| | - Melinda J. Waterman
- Securing Antarctica's Environmental Future, School of Earth, Atmospheric and Life SciencesUniversity of WollongongWollongongNew South WalesAustralia
| | - Justine D. Shaw
- Securing Antarctica's Environmental Future, School of Biology and Environmental ScienceQueensland University of TechnologyBrisbaneQLDAustralia
| | - Dana M. Bergstrom
- Australian Antarctic Division, Department of AgricultureWater and the EnvironmentKingstonTASAustralia
- Global Challenges ProgramUniversity of WollongongWollongongNew South WalesAustralia
| | - Heather J. Lynch
- Department of Ecology and EvolutionStony Brook UniversityStony BrookNew YorkUSA
| | - Diana H. Wall
- Department of Biology and School of Global Environmental SustainabilityColorado State UniversityFort CollinsColoradoUSA
| | - Sharon A. Robinson
- Securing Antarctica's Environmental Future, School of Earth, Atmospheric and Life SciencesUniversity of WollongongWollongongNew South WalesAustralia
- Global Challenges ProgramUniversity of WollongongWollongongNew South WalesAustralia
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2
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Jackson AC, Jorna J, Chaston JM, Adams BJ. Glacial Legacies: Microbial Communities of Antarctic Refugia. BIOLOGY 2022; 11:biology11101440. [PMID: 36290344 PMCID: PMC9598129 DOI: 10.3390/biology11101440] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 11/06/2022]
Abstract
In the cold deserts of the McMurdo Dry Valleys (MDV) the suitability of soil for microbial life is determined by both contemporary processes and legacy effects. Climatic changes and accompanying glacial activity have caused local extinctions and lasting geochemical changes to parts of these soil ecosystems over several million years, while areas of refugia may have escaped these disturbances and existed under relatively stable conditions. This study describes the impact of historical glacial and lacustrine disturbance events on microbial communities across the MDV to investigate how this divergent disturbance history influenced the structuring of microbial communities across this otherwise very stable ecosystem. Soil bacterial communities from 17 sites representing either putative refugia or sites disturbed during the Last Glacial Maximum (LGM) (22-17 kya) were characterized using 16 S metabarcoding. Regardless of geographic distance, several putative refugia sites at elevations above 600 m displayed highly similar microbial communities. At a regional scale, community composition was found to be influenced by elevation and geographic proximity more so than soil geochemical properties. These results suggest that despite the extreme conditions, diverse microbial communities exist in these putative refugia that have presumably remained undisturbed at least through the LGM. We suggest that similarities in microbial communities can be interpreted as evidence for historical climate legacies on an ecosystem-wide scale.
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Affiliation(s)
- Abigail C. Jackson
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
- Correspondence: (A.C.J.); (J.J.)
| | - Jesse Jorna
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
- Correspondence: (A.C.J.); (J.J.)
| | - John M. Chaston
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA
| | - Byron J. Adams
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
- Monte L. Bean Museum, Brigham Young University, Provo, UT 84602, USA
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3
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Soil Nematodes as the Silent Sufferers of Climate-Induced Toxicity: Analysing the Outcomes of Their Interactions with Climatic Stress Factors on Land Cover and Agricultural Production. Appl Biochem Biotechnol 2022; 195:2519-2586. [PMID: 35593954 DOI: 10.1007/s12010-022-03965-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 05/10/2022] [Indexed: 11/02/2022]
Abstract
Unsustainable anthropogenic activities over the last few decades have resulted in alterations of the global climate. It can be perceived through changes in the rainfall patterns and rise in mean annual temperatures. Climatic stress factors exert their effects on soil health mainly by modifying the soil microenvironments where the soil fauna reside. Among the members of soil fauna, the soil nematodes have been found to be sensitive to these stress factors primarily because of their low tolerance limits. Additionally, because of their higher and diverse trophic positions in the soil food web they can integrate the effects of many stress factors acting together. This is important because under natural conditions the climatic stress factors do not exert their effect individually. Rather, they interact amongst themselves and other abiotic stress factors in the soil to generate their impacts. Some of these interactions may be synergistic while others may be antagonistic. As such, it becomes very difficult to assess their impacts on soil health by simply analysing the physicochemical properties of soil. This makes soil nematodes outstanding candidates for studying the effects of climatic stress factors on soil biology. The knowledge obtained therefrom can be used to design sustainable agricultural practices because most of the conventional techniques aim at short-term benefits with complete disregard of soil biology. This can partly ensure food security in the coming decades for the expanding population. Moreover, understanding soil biology can help to preserve landscapes that have developed over long periods of climatic stability and belowground soil biota interactions.
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4
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Jiang X, Van Horn DJ, Okie JG, Buelow HN, Schwartz E, Colman DR, Feeser KL, Takacs-Vesbach CD. Limits to the three domains of life: lessons from community assembly along an Antarctic salinity gradient. Extremophiles 2022; 26:15. [PMID: 35296937 DOI: 10.1007/s00792-022-01262-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/10/2022] [Indexed: 02/01/2023]
Abstract
Extremophiles exist among all three domains of life; however, physiological mechanisms for surviving harsh environmental conditions differ among Bacteria, Archaea and Eukarya. Consequently, we expect that domain-specific variation of diversity and community assembly patterns exist along environmental gradients in extreme environments. We investigated inter-domain community compositional differences along a high-elevation salinity gradient in the McMurdo Dry Valleys, Antarctica. Conductivity for 24 soil samples collected along the gradient ranged widely from 50 to 8355 µS cm-1. Taxonomic richness varied among domains, with a total of 359 bacterial, 2 archaeal, 56 fungal, and 69 non-fungal eukaryotic operational taxonomic units (OTUs). Richness for bacteria, archaea, fungi, and non-fungal eukaryotes declined with increasing conductivity (all P < 0.05). Principal coordinate ordination analysis (PCoA) revealed significant (ANOSIM R = 0.97) groupings of low/high salinity bacterial OTUs, while OTUs from other domains were not significantly clustered. Bacterial beta diversity was unimodally distributed along the gradient and had a nested structure driven by species losses, whereas in fungi and non-fungal eukaryotes beta diversity declined monotonically without strong evidence of nestedness. Thus, while increased salinity acts as a stressor in all domains, the mechanisms driving community assembly along the gradient differ substantially between the domains.
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Affiliation(s)
- Xiaoben Jiang
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, 48824, USA
| | - David J Van Horn
- Department of Biology, MSC03 2020 1UNM, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Jordan G Okie
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Heather N Buelow
- Department of Biology, MSC03 2020 1UNM, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Egbert Schwartz
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Daniel R Colman
- Department of Biology, MSC03 2020 1UNM, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Kelli L Feeser
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
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5
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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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6
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Thompson AR, Roth-Monzón AJ, Aanderud ZT, Adams BJ. Phagotrophic Protists and Their Associates: Evidence for Preferential Grazing in an Abiotically Driven Soil Ecosystem. Microorganisms 2021; 9:1555. [PMID: 34442632 PMCID: PMC8398437 DOI: 10.3390/microorganisms9081555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 11/17/2022] Open
Abstract
The complex relationship between ecosystem function and soil food web structure is governed by species interactions, many of which remain unmapped. Phagotrophic protists structure soil food webs by grazing the microbiome, yet their involvement in intraguild competition, susceptibility to predator diversity, and grazing preferences are only vaguely known. These species-dependent interactions are contextualized by adjacent biotic and abiotic processes, and thus obfuscated by typically high soil biodiversity. Such questions may be investigated in the McMurdo Dry Valleys (MDV) of Antarctica because the physical environment strongly filters biodiversity and simplifies the influence of abiotic factors. To detect the potential interactions in the MDV, we analyzed the co-occurrence among shotgun metagenome sequences for associations suggestive of intraguild competition, predation, and preferential grazing. In order to control for confounding abiotic drivers, we tested co-occurrence patterns against various climatic and edaphic factors. Non-random co-occurrence between phagotrophic protists and other soil fauna was biotically driven, but we found no support for competition or predation. However, protists predominately associated with Proteobacteria and avoided Actinobacteria, suggesting grazing preferences were modulated by bacterial cell-wall structure and growth rate. Our study provides a critical starting-point for mapping protist interactions in native soils and highlights key trends for future targeted molecular and culture-based approaches.
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Affiliation(s)
- Andrew R. Thompson
- Department of Biology, Brigham Young University, Provo, UT 84602, USA; (A.J.R.-M.); (B.J.A.)
| | - Andrea J. Roth-Monzón
- Department of Biology, Brigham Young University, Provo, UT 84602, USA; (A.J.R.-M.); (B.J.A.)
- Department of Ecology and Evolutionary Biology, University of Connecticut, Mansfield, CT 06269, USA
| | - Zachary T. Aanderud
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA;
| | - Byron J. Adams
- Department of Biology, Brigham Young University, Provo, UT 84602, USA; (A.J.R.-M.); (B.J.A.)
- Monte L. Bean Life Science Museum, Brigham Young University, Provo, UT 84602, USA
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7
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Bottos EM, Laughlin DC, Herbold CW, Lee CK, McDonald IR, Cary SC. Abiotic factors influence patterns of bacterial diversity and community composition in the Dry Valleys of Antarctica. FEMS Microbiol Ecol 2020; 96:5815075. [PMID: 32239205 DOI: 10.1093/femsec/fiaa042] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 03/23/2020] [Indexed: 11/13/2022] Open
Abstract
The Dry Valleys of Antarctica are a unique ecosystem of simple trophic structure, where the abiotic factors that influence soil bacterial communities can be resolved in the absence of extensive biotic interactions. This study evaluated the degree to which aspects of topographic, physicochemical and spatial variation explain patterns of bacterial richness and community composition in 471 soil samples collected across a 220 square kilometer landscape in Southern Victoria Land. Richness was most strongly influenced by physicochemical soil properties, particularly soil conductivity, though significant trends with several topographic and spatial variables were also observed. Structural equation modeling (SEM) supported a final model in which variation in community composition was best explained by physicochemical variables, particularly soil water content, and where the effects of topographic variation were largely mediated through their influence on physicochemical variables. Community dissimilarity increased with distance between samples, and though most of this variation was explained by topographic and physicochemical variation, a small but significant relationship remained after controlling for this environmental variation. As the largest survey of terrestrial bacterial communities of Antarctica completed to date, this work provides fundamental knowledge of the Dry Valleys ecosystem, and has implications globally for understanding environmental factors that influence bacterial distributions.
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Affiliation(s)
- Eric M Bottos
- School of Science, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.,The International Centre for Terrestrial Antarctic Research, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Daniel C Laughlin
- School of Science, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Craig W Herbold
- School of Science, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.,The International Centre for Terrestrial Antarctic Research, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Charles K Lee
- School of Science, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.,The International Centre for Terrestrial Antarctic Research, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Ian R McDonald
- School of Science, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.,The International Centre for Terrestrial Antarctic Research, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - S Craig Cary
- School of Science, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.,The International Centre for Terrestrial Antarctic Research, The University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
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8
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Estimating microbial mat biomass in the McMurdo Dry Valleys, Antarctica using satellite imagery and ground surveys. Polar Biol 2020. [DOI: 10.1007/s00300-020-02742-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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9
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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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10
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Sommers P, Fontenele RS, Kringen T, Kraberger S, Porazinska DL, Darcy JL, Schmidt SK, Varsani A. Single-Stranded DNA Viruses in Antarctic Cryoconite Holes. Viruses 2019; 11:E1022. [PMID: 31689942 PMCID: PMC6893807 DOI: 10.3390/v11111022] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 10/28/2019] [Accepted: 10/31/2019] [Indexed: 12/28/2022] Open
Abstract
Antarctic cryoconite holes, or small melt-holes in the surfaces of glaciers, create habitable oases for isolated microbial communities with tightly linked microbial population structures. Viruses may influence the dynamics of polar microbial communities, but the viromes of the Antarctic cryoconite holes have yet to be characterized. We characterize single-stranded DNA (ssDNA) viruses from three cryoconite holes in the Taylor Valley, Antarctica, using metagenomics. Half of the assembled metagenomes cluster with those in the viral family Microviridae (n = 7), and the rest with unclassified circular replication associated protein (Rep)-encoding single-stranded (CRESS) DNA viruses (n = 7). An additional 18 virus-like circular molecules encoding either a Rep, a capsid protein gene, or other unidentified but viral-like open reading frames were identified. The samples from which the genomes were identified show a strong gradient in microbial diversity and abundances, and the number of viral genomes detected in each sample mirror that gradient. Additionally, one of the CRESS genomes assembled here shares ~90% genome-wide pairwise identity with a virus identified from a freshwater pond on the McMurdo Ice Shelf (Antarctica). Otherwise, the similarity of these viruses to those previously identified is relatively low. Together, these patterns are consistent with the presence of a unique regional virome present in fresh water host populations of the McMurdo Dry Valley region.
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Affiliation(s)
- Pacifica Sommers
- Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Rafaela S Fontenele
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA.
| | - Tayele Kringen
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA.
| | - Simona Kraberger
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA.
| | - Dorota L Porazinska
- Entomology and Nematology Department, University of Florida, Gainesville, FL 32611, USA.
| | - John L Darcy
- Division of Biomedical Informatics and Personalized Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - Steven K Schmidt
- Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO 80309, USA.
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ 85287-5001, USA.
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, University of Cape Town, Observatory, Cape Town 7701, South Africa.
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11
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Geyer KM, Barrett JE. Unimodal productivity–diversity relationships among bacterial communities in a simple polar soil ecosystem. Environ Microbiol 2019; 21:2523-2532. [DOI: 10.1111/1462-2920.14639] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/20/2019] [Accepted: 04/23/2019] [Indexed: 11/27/2022]
Affiliation(s)
- Kevin M. Geyer
- Department of Natural Resources and the EnvironmentUniversity of New Hampshire Durham New Hampshire USA
- Department of Biological SciencesVirginia Polytechnic Institute and State University Blacksburg Virginia USA
| | - John E. Barrett
- Department of Biological SciencesVirginia Polytechnic Institute and State University Blacksburg Virginia USA
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12
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Treonis AM, Sutton KA, Unangst SK, Wren JE, Dragan ES, McQueen JP. Soil organic matter determines the distribution and abundance of nematodes on alluvial fans in Death Valley, California. Ecosphere 2019. [DOI: 10.1002/ecs2.2659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Amy M. Treonis
- Department of Biology University of Richmond Richmond Virginia 23173 USA
| | - Kelsey A. Sutton
- Department of Biology University of Richmond Richmond Virginia 23173 USA
| | | | - Julia E. Wren
- Department of Biology University of Richmond Richmond Virginia 23173 USA
| | - Emma S. Dragan
- Department of Biology University of Richmond Richmond Virginia 23173 USA
| | - J. Parr McQueen
- Department of Biology University of Richmond Richmond Virginia 23173 USA
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13
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Sommers P, Darcy JL, Gendron EMS, Stanish LF, Bagshaw EA, Porazinska DL, Schmidt SK. Diversity patterns of microbial eukaryotes mirror those of bacteria in Antarctic cryoconite holes. FEMS Microbiol Ecol 2019; 94:4705885. [PMID: 29228256 DOI: 10.1093/femsec/fix167] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/29/2017] [Indexed: 11/13/2022] Open
Abstract
Ice-lidded cryoconite holes on glaciers in the Taylor Valley, Antarctica, provide a unique system of natural mesocosms for studying community structure and assembly. We used high-throughput DNA sequencing to characterize both microbial eukaryotic communities and bacterial communities within cryoconite holes across three glaciers to study similarities in their spatial patterns. We expected that the alpha (phylogenetic diversity) and beta (pairwise community dissimilarity) diversity patterns of eukaryotes in cryoconite holes would be related to those of bacteria, and that they would be related to the biogeochemical gradient within the Taylor Valley. We found that eukaryotic alpha and beta diversity were strongly related to those of bacteria across scales ranging from 140 m to 41 km apart. Alpha diversity of both was significantly related to position in the valley and surface area of the cryoconite hole, with pH also significantly correlated with the eukaryotic diversity. Beta diversity for both bacteria and eukaryotes was significantly related to position in the valley, with bacterial beta diversity also related to nitrate. These results are consistent with transport of sediments onto glaciers occurring primarily at local scales relative to the size of the valley, thus creating feedbacks in local chemistry and diversity.
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Affiliation(s)
- Pacifica Sommers
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - John L Darcy
- Department of Botany, University of Hawai'i at Manoa, Honolulu, HI 96822, USA
| | - Eli M S Gendron
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO 80309, USA.,Department of Molecular, Cellular, and Development Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Lee F Stanish
- National Ecological Observatory Network, Boulder, CO 80301, USA
| | | | - Dorota L Porazinska
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Steven K Schmidt
- Department of Ecology and Evolutionary Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
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14
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Feeser KL, Van Horn DJ, Buelow HN, Colman DR, McHugh TA, Okie JG, Schwartz E, Takacs-Vesbach CD. Local and Regional Scale Heterogeneity Drive Bacterial Community Diversity and Composition in a Polar Desert. Front Microbiol 2018; 9:1928. [PMID: 30186257 PMCID: PMC6110917 DOI: 10.3389/fmicb.2018.01928] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/30/2018] [Indexed: 02/01/2023] Open
Abstract
The distribution of organisms in an environment is neither uniform nor random but is instead spatially patterned. The factors that control this patterning are complex and the underlying mechanisms are poorly understood. Soil microbes are critical to ecosystem function but exhibit highly complex distributions and community dynamics due in large part to the scale-dependent effects of environmental heterogeneity. To better understand the impact of environmental heterogeneity on the distribution of soil microbes, we sequenced the 16S rRNA gene from bacterial communities in the microbe-dominated polar desert ecosystem of the McMurdo Dry Valleys (MDV), Antarctica. Significant differences in key edaphic variables and alpha diversity were observed among the three lake basins of the Taylor Valley (Kruskal-Wallis; pH: χ2 = 68.89, P < 0.001, conductivity: χ2 = 35.03, P < 0.001, observed species: χ2 = 7.98, P = 0.019 and inverse Simpson: χ2 = 18.52, P < 0.001) and each basin supported distinctive microbial communities (ANOSIM R = 0.466, P = 0.001, random forest ratio of 14.1). However, relationships between community structure and edaphic characteristics were highly variable and contextual, ranging in magnitude and direction across regional, basin, and local scales. Correlations among edaphic factors (pH and soil conductivity) and the relative abundance of specific phyla were most pronounced along local environmental gradients in the Lake Fryxell basin where Acidobacteria, Bacteroidetes, and Proteobacteria declined while Deinococcus-Thermus and Gemmatimonadetes increased with soil conductivity (all P < 0.1). Species richness was most strongly related to the soil conductivity gradient present within this study system. We suggest that the relative importance of pH versus soil conductivity in structuring microbial communities is related to the length of edaphic gradients and the spatial scale of sampling. These results highlight the importance of conducting studies over large ranges of key environmental gradients and across multiple spatial scales to assess the influence of environmental heterogeneity on the composition and diversity of microbial communities.
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Affiliation(s)
- Kelli L. Feeser
- Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - David J. Van Horn
- Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - Heather N. Buelow
- Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - Daniel R. Colman
- Department of Biology, University of New Mexico, Albuquerque, NM, United States
| | - Theresa A. McHugh
- Department of Biological Sciences, Colorado Mesa University, Grand Junction, CO, United States
| | - Jordan G. Okie
- School of Life Sciences, School of Earth and Space Exploration, Arizona State University, Tempe, AZ, United States
| | - Egbert Schwartz
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, United States
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15
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Liddicoat C, Bi P, Waycott M, Glover J, Breed M, Weinstein P. Ambient soil cation exchange capacity inversely associates with infectious and parasitic disease risk in regional Australia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 626:117-125. [PMID: 29335166 DOI: 10.1016/j.scitotenv.2018.01.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/08/2018] [Accepted: 01/08/2018] [Indexed: 06/07/2023]
Abstract
Human contact with soil may be important for building and maintaining normal healthy immune defence mechanisms, however this idea remains untested at the population-level. In this continent-wide, cross-sectional study we examine the possible public health benefit of ambient exposures to soil of high cation exchange capacity (CEC), a surrogate for potential immunomodulatory soil microbial diversity. We compare distributions of normalized mean 2011/12-2012/13 age-standardized public hospital admission rates (cumulative incidence) for infectious and parasitic diseases across regional Australia (representing an average of 29,516 patients/year in 228 local government areas), within tertiles of socioeconomic status and soil exposure. To test the significance of soil CEC, we use probabilistic individual-level environmental exposure data (with or without soil), and group-level variables, in robust non-parametric multilevel modelling to predict disease rates in unseen groups. Our results show that in socioeconomically-deprived areas with high CEC soils, rates of infectious and parasitic disease are significantly lower than areas with low CEC soils. Also, health inequality (relative risk) due to socioeconomic status is significantly lower in areas with high CEC soils compared to low CEC soils (Δ relative risk = 0.47; 95% CI: 0.13, 0.82). Including soil exposure when modelling rates of infectious and parasitic disease significantly improves prediction performance, explaining an additional 7.5% (Δ r2 = 0.075; 95% CI: 0.05, 0.10) of variation in disease risk, in local government areas that were not used for model building. Our findings suggest that exposure to high CEC soils (typically high soil biodiversity) associates with reduced risk of infectious and parasitic diseases, particularly in lower socioeconomic areas.
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Affiliation(s)
- Craig Liddicoat
- School of Biological Sciences and The Environment Institute, The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia.
| | - Peng Bi
- School of Public Health, The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Michelle Waycott
- School of Biological Sciences and The Environment Institute, The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia; Department of Environment, Water and Natural Resources, GPO Box 1047, Adelaide, SA 5001, Australia
| | - John Glover
- Public Health Information Development Unit, Torrens University Australia, Level 1, 200 Victoria Square, Adelaide, SA 5000, Australia
| | - Martin Breed
- School of Biological Sciences and The Environment Institute, The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Philip Weinstein
- School of Biological Sciences and The Environment Institute, The University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
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16
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Ma H, Yan W, Xiao X, Shi G, Li Y, Sun B, Dou Y, Zhang Y. Ex Situ Culturing Experiments Revealed Psychrophilic Hydrogentrophic Methanogenesis Being the Potential Dominant Methane-Producing Pathway in Subglacial Sediment in Larsemann Hills, Antarctic. Front Microbiol 2018. [PMID: 29515536 PMCID: PMC5826372 DOI: 10.3389/fmicb.2018.00237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
It was recognized only recently that subglacial ecosystems support considerable methanogenic activity, thus significantly contributing the global methane production. However, only limited knowledge is available on the physiological characteristics of this kind of methanogenic community because of the technical constraints associated with sampling and cultivation under corresponding environmental conditions. To elucidate methanogenesis beneath the glacial margin in East Antarctic Ice Sheet, we took an integrated approach that included cultivation of microbes associated with the sediment samples in the lab and analysis of mcrA gene therein. After 7 months of incubation, the highest rate of methanogenesis [398 (pmol/day)/gram] was observed at 1°C on a supply of H2. The rates of methanogenesis were lower on acetate or unamended substrate than on H2. The rates on these two substrates increased when the temperature was raised. Methanomicrobiales predominated before and after prolonged incubation, regardless whether H2, acetate, or unamended substrate were the energy source. Therefore, it was inferred that psychrophilic hydrogenotrophic methanogenesis was the primary methane-producing pathway in the subglacial ecosystem we sampled. These findings highlight the effects of temperature and substrate on potential methanogenesis in the subglacial sediment of this area, and may help us for a better estimation on the Antarctica methane production in a changing climate.
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Affiliation(s)
- Hongmei Ma
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Wenkai Yan
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Xiao
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Guitao Shi
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Yuansheng Li
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Bo Sun
- SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China
| | - Yinke Dou
- College of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan, China
| | - Yu Zhang
- State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai, China.,Institute of Oceanography, Shanghai Jiao Tong University, Shanghai, China
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17
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Delgado-Baquerizo M, Reith F, Dennis PG, Hamonts K, Powell JR, Young A, Singh BK, Bissett A. Ecological drivers of soil microbial diversity and soil biological networks in the Southern Hemisphere. Ecology 2018; 99:583-596. [PMID: 29315530 DOI: 10.1002/ecy.2137] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/08/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023]
Abstract
The ecological drivers of soil biodiversity in the Southern Hemisphere remain underexplored. Here, in a continental survey comprising 647 sites, across 58 degrees of latitude between tropical Australia and Antarctica, we evaluated the major ecological patterns in soil biodiversity and relative abundance of ecological clusters within a co-occurrence network of soil bacteria, archaea and eukaryotes. Six major ecological clusters (modules) of co-occurring soil taxa were identified. These clusters exhibited strong shifts in their relative abundances with increasing distance from the equator. Temperature was the major environmental driver of the relative abundance of ecological clusters when Australia and Antarctica are analyzed together. Temperature, aridity, soil properties and vegetation types were the major drivers of the relative abundance of different ecological clusters within Australia. Our data supports significant reductions in the diversity of bacteria, archaea and eukaryotes in Antarctica vs. Australia linked to strong reductions in temperature. However, we only detected small latitudinal variations in soil biodiversity within Australia. Different environmental drivers regulate the diversity of soil archaea (temperature and soil carbon), bacteria (aridity, vegetation attributes and pH) and eukaryotes (vegetation type and soil carbon) across Australia. Together, our findings provide new insights into the mechanisms driving soil biodiversity in the Southern Hemisphere.
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Affiliation(s)
- Manuel Delgado-Baquerizo
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, 2751, Australia.,Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, 80309, USA.,Departamento de Biología, Geología, Física y Química Inorgánica, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, c/ Tulipán s/n, Móstoles, 28933, Spain
| | - Frank Reith
- Department of Molecular and Cellular Biology, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia.,Land and Water, Environmental Contaminant Mitigation and Technologies, PMB2, Glen Osmond, South Australia, 5064, Australia
| | - Paul G Dennis
- School of Earth and Environmental Sciences, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Kelly Hamonts
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, 2751, Australia
| | - Jeff R Powell
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, 2751, Australia
| | - Andrew Young
- National Research Collections Australia, CSIRO, Canberra, Australian Capital Territory, 2601, Australia
| | - Brajesh K Singh
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, 2751, Australia.,Global Centre for Land-Based Innovation, Western Sydney University, Penrith South DC, New South Wales, 2751, Australia
| | - Andrew Bissett
- CSIRO, Oceans and Atmosphere, Hobart, Tasmania, 7000, Australia
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18
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Andriuzzi WS, Adams BJ, Barrett JE, Virginia RA, Wall DH. Observed trends of soil fauna in the Antarctic Dry Valleys: early signs of shifts predicted under climate change. Ecology 2018; 99:312-321. [PMID: 29315515 DOI: 10.1002/ecy.2090] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/06/2017] [Accepted: 11/08/2017] [Indexed: 11/09/2022]
Abstract
Long-term observations of ecological communities are necessary for generating and testing predictions of ecosystem responses to climate change. We investigated temporal trends and spatial patterns of soil fauna along similar environmental gradients in three sites of the McMurdo Dry Valleys, Antarctica, spanning two distinct climatic phases: a decadal cooling trend from the early 1990s through the austral summer of February 2001, followed by a shift to the current trend of warming summers and more frequent discrete warming events. After February 2001, we observed a decline in the dominant species (the nematode Scottnema lindsayae) and increased abundance and expanded distribution of less common taxa (rotifers, tardigrades, and other nematode species). Such diverging responses have resulted in slightly greater evenness and spatial homogeneity of taxa. However, total abundance of soil fauna appears to be declining, as positive trends of the less common species so far have not compensated for the declining numbers of the dominant species. Interannual variation in the proportion of juveniles in the dominant species was consistent across sites, whereas trends in abundance varied more. Structural equation modeling supports the hypothesis that the observed biological trends arose from dissimilar responses by dominant and less common species to pulses of water availability resulting from enhanced ice melt. No direct effects of mean summer temperature were found, but there is evidence of indirect effects via its weak but significant positive relationship with soil moisture. Our findings show that combining an understanding of species responses to environmental change with long-term observations in the field can provide a context for validating and refining predictions of ecological trends in the abundance and diversity of soil fauna.
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Affiliation(s)
- W S Andriuzzi
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - B J Adams
- Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Brigham Young University, Provo, Utah, 84602, USA
| | - J E Barrett
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, 24061, USA
| | - R A Virginia
- Environmental Studies Program, Dartmouth College, Hanover, New Hampshire, 03755, USA
| | - D H Wall
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA.,School of Global Environmental Sustainability, Colorado State University, Fort Collins, Colorado, 80523, USA
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19
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Higuera-Llantén S, Vásquez-Ponce F, Núñez-Gallegos M, Pavlov MS, Marshall S, Olivares-Pacheco J. Phenotypic and genotypic characterization of a novel multi-antibiotic-resistant, alginate hyperproducing strain of Pseudomonas mandelii isolated in Antarctica. Polar Biol 2017. [DOI: 10.1007/s00300-017-2206-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Knox MA, Andriuzzi WS, Buelow HN, Takacs-Vesbach C, Adams BJ, Wall DH. Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze-thaw cycles, in the Antarctic Dry Valleys. Ecol Lett 2017; 20:1242-1249. [PMID: 28797136 DOI: 10.1111/ele.12819] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 06/30/2017] [Accepted: 07/09/2017] [Indexed: 11/30/2022]
Abstract
Altered temperature profiles resulting in increased warming and freeze-thaw cycle (FTC) frequency pose great ecological challenges to organisms in alpine and polar ecosystems. We performed a laboratory microcosm experiment to investigate how temperature variability affects soil bacterial cell numbers, and abundance and traits of soil microfauna (the microbivorous nematode Scottnema lindsayae) from McMurdo Dry Valleys, Antarctica. FTCs and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTCs reduced both bacterial and nematode abundance, but bacterial cell numbers also declined under warming, demonstrating decoupled consumer-prey responses. We predict that higher occurrence of FTCs in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTCs could lead to divergent responses in soil bacteria and their microinvertebrate consumers, potentially affecting energy and nutrient transfer rates in soil food webs of cold ecosystems.
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Affiliation(s)
- Matthew A Knox
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.,Hopkirk Research Institute, IVABS, Massey University, Private Bag 11-222, Palmerston North, 4474, New Zealand
| | - Walter S Andriuzzi
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Heather N Buelow
- Department of Biology, University of New Mexico, Albuquerque, NM, 87131, USA
| | | | - Byron J Adams
- Department of Biology, Evolutionary Ecology Laboratories, and Monte L. Bean Museum, Brigham Young University, Provo, UT, 84602, USA
| | - Diana H Wall
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA.,School of Global Environmental Sustainability, Colorado State University, Fort Collins, CO, 80523, USA
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21
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Geyer KM, Takacs-Vesbach CD, Gooseff MN, Barrett JE. Primary productivity as a control over soil microbial diversity along environmental gradients in a polar desert ecosystem. PeerJ 2017; 5:e3377. [PMID: 28761776 PMCID: PMC5530992 DOI: 10.7717/peerj.3377] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/04/2017] [Indexed: 11/20/2022] Open
Abstract
Primary production is the fundamental source of energy to foodwebs and ecosystems, and is thus an important constraint on soil communities. This coupling is particularly evident in polar terrestrial ecosystems where biological diversity and activity is tightly constrained by edaphic gradients of productivity (e.g., soil moisture, organic carbon availability) and geochemical severity (e.g., pH, electrical conductivity). In the McMurdo Dry Valleys of Antarctica, environmental gradients determine numerous properties of soil communities and yet relatively few estimates of gross or net primary productivity (GPP, NPP) exist for this region. Here we describe a survey utilizing pulse amplitude modulation (PAM) fluorometry to estimate rates of GPP across a broad environmental gradient along with belowground microbial diversity and decomposition. PAM estimates of GPP ranged from an average of 0.27 μmol O2/m2/s in the most arid soils to an average of 6.97 μmol O2/m2/s in the most productive soils, the latter equivalent to 217 g C/m2/y in annual NPP assuming a 60 day growing season. A diversity index of four carbon-acquiring enzyme activities also increased with soil productivity, suggesting that the diversity of organic substrates in mesic environments may be an additional driver of microbial diversity. Overall, soil productivity was a stronger predictor of microbial diversity and enzymatic activity than any estimate of geochemical severity. These results highlight the fundamental role of environmental gradients to control community diversity and the dynamics of ecosystem-scale carbon pools in arid systems.
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Affiliation(s)
- Kevin M. Geyer
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA
| | | | - Michael N. Gooseff
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA
- Department of Civil, Environmental and Architectural Engineering, University of Colorado, Boulder, CO, USA
| | - John E. Barrett
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, USA
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22
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Yan X, Wang K, Song L, Wang X, Wu D. Daytime warming has stronger negative effects on soil nematodes than night-time warming. Sci Rep 2017; 7:44888. [PMID: 28317914 PMCID: PMC5358016 DOI: 10.1038/srep44888] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/14/2017] [Indexed: 11/09/2022] Open
Abstract
Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatment significantly decreased soil nematodes density, and night-time warming treatment marginally affected the density. The response of bacterivorous nematode and fungivorous nematode to experimental warming showed the same trend with the total density. Redundancy analysis revealed an opposite effect of soil moisture and soil temperature, and the most important of soil moisture and temperature in night-time among the measured environment factors, affecting soil nematode community. Our findings suggested that daily minimum temperature and warming induced drying are most important factors affecting soil nematode community under the current global asymmetric warming.
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Affiliation(s)
- Xiumin Yan
- School of Geography and Tourism, Guizhou Education University, Guiyang 550018, P. R. China.,Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, P. R. China
| | - Kehong Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, P. R. China.,College of Resources and Environmental Science, Chongqing University, Chongqing 40044, P. R. China
| | - Lihong Song
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, P. R. China.,College of Agriculture, Guizhou University, Guiyang 550025, P. R. China
| | - Xuefeng Wang
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, P. R. China.,School of Chinese Medicinal Materials, Jilin Agricultural University, Changchun 130117, P. R. China
| | - Donghui Wu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130012, P. R. China
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23
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Daytime warming has stronger negative effects on soil nematodes than night-time warming. Sci Rep 2017; 7:108. [PMID: 28273897 PMCID: PMC5428061 DOI: 10.1038/s41598-017-00218-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/14/2017] [Indexed: 11/18/2022] Open
Abstract
Warming of the climate system is unequivocal, that is, stronger warming during night-time than during daytime. Here we focus on how soil nematodes respond to the current asymmetric warming. A field infrared heating experiment was performed in the western of the Songnen Plain, Northeast China. Three warming modes, i.e. daytime warming, night-time warming and diurnal warming, were taken to perform the asymmetric warming condition. Our results showed that the daytime and diurnal warming treatment significantly decreased soil nematodes density, and night-time warming treatment marginally affected the density. The response of bacterivorous nematode and fungivorous nematode to experimental warming showed the same trend with the total density. Redundancy analysis revealed an opposite effect of soil moisture and soil temperature, and the most important of soil moisture and temperature in night-time among the measured environment factors, affecting soil nematode community. Our findings suggested that daily minimum temperature and warming induced drying are most important factors affecting soil nematode community under the current global asymmetric warming.
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24
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Okie JG, Van Horn DJ, Storch D, Barrett JE, Gooseff MN, Kopsova L, Takacs-Vesbach CD. Niche and metabolic principles explain patterns of diversity and distribution: theory and a case study with soil bacterial communities. Proc Biol Sci 2016; 282:20142630. [PMID: 26019154 DOI: 10.1098/rspb.2014.2630] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The causes of biodiversity patterns are controversial and elusive due to complex environmental variation, covarying changes in communities, and lack of baseline and null theories to differentiate straightforward causes from more complex mechanisms. To address these limitations, we developed general diversity theory integrating metabolic principles with niche-based community assembly. We evaluated this theory by investigating patterns in the diversity and distribution of soil bacteria taxa across four orders of magnitude variation in spatial scale on an Antarctic mountainside in low complexity, highly oligotrophic soils. Our theory predicts that lower temperatures should reduce taxon niche widths along environmental gradients due to decreasing growth rates, and the changing niche widths should lead to contrasting α- and β-diversity patterns. In accord with the predictions, α-diversity, niche widths and occupancies decreased while β-diversity increased with increasing elevation and decreasing temperature. The theory also successfully predicts a hump-shaped relationship between α-diversity and pH and a negative relationship between α-diversity and salinity. Thus, a few simple principles explained systematic microbial diversity variation along multiple gradients. Such general theory can be used to disentangle baseline effects from more complex effects of temperature and other variables on biodiversity patterns in a variety of ecosystems and organisms.
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Affiliation(s)
- Jordan G Okie
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - David J Van Horn
- Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - David Storch
- Center for Theoretical Study, Charles University, Prague, Czech Republic Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic Department of Biological Sciences, Virginia Technological Institute, Blacksburg, VA, USA
| | - John E Barrett
- Department of Biological Sciences, Virginia Technological Institute, Blacksburg, VA, USA
| | - Michael N Gooseff
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA
| | - Lenka Kopsova
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
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25
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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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26
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Pulschen AA, Rodrigues F, Duarte RTD, Araujo GG, Santiago IF, Paulino-Lima IG, Rosa CA, Kato MJ, Pellizari VH, Galante D. UV-resistant yeasts isolated from a high-altitude volcanic area on the Atacama Desert as eukaryotic models for astrobiology. Microbiologyopen 2015; 4:574-88. [PMID: 26147800 PMCID: PMC4554453 DOI: 10.1002/mbo3.262] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 03/18/2015] [Accepted: 03/27/2015] [Indexed: 11/17/2022] Open
Abstract
The Sairecabur volcano (5971 m), in the Atacama Desert, is a high-altitude extreme environment with high daily temperature variations, acidic soils, intense UV radiation, and low availability of water. Four different species of yeasts were isolated from this region using oligotrophic media, identified and characterized for their tolerance to extreme conditions. rRNA sequencing revealed high identity (>98%) to Cryptococcus friedmannii, Exophiala sp., Holtermanniella watticus, and Rhodosporidium toruloides. To our knowledge, this is the first report of these yeasts in the Atacama Desert. All isolates showed high resistance to UV-C, UV-B and environmental-UV radiation, capacity to grow at moderate saline media (0.75–2.25 mol/L NaCl) and at moderate to cold temperatures, being C. friedmannii and H. watticus able to grow in temperatures down to −6.5°C. The presence of pigments, analyzed by Raman spectroscopy, correlated with UV resistance in some cases, but there is evidence that, on the natural environment, other molecular mechanisms may be as important as pigmentation, which has implications for the search of spectroscopic biosignatures on planetary surfaces. Due to the extreme tolerances of the isolated yeasts, these organisms represent interesting eukaryotic models for astrobiological purposes.
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Affiliation(s)
- André A Pulschen
- Chemistry Institute, Universidade de São Paulo, São Paulo, Brazil
| | - Fabio Rodrigues
- Chemistry Institute, Universidade de São Paulo, São Paulo, Brazil
| | - Rubens T D Duarte
- Microbiology, Immunology and Parasitology Department, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Gabriel G Araujo
- Interunities Graduate Program in Biotechnology, Universidade de São Paulo, São Paulo, Brazil.,Brazilian Synchrotron Light Laboratory, Campinas, Brazil
| | - Iara F Santiago
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ivan G Paulino-Lima
- NASA Postdoctoral Program Fellow at NASA Ames Research Center, Moffett Field, California
| | - Carlos A Rosa
- Department of Microbiology, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Massuo J Kato
- Chemistry Institute, Universidade de São Paulo, São Paulo, Brazil
| | | | - Douglas Galante
- Interunities Graduate Program in Biotechnology, Universidade de São Paulo, São Paulo, Brazil.,Brazilian Synchrotron Light Laboratory, Campinas, Brazil
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27
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Niederberger TD, Sohm JA, Gunderson TE, Parker AE, Tirindelli J, Capone DG, Carpenter EJ, Cary SC. Microbial community composition of transiently wetted Antarctic Dry Valley soils. Front Microbiol 2015; 6:9. [PMID: 25674080 PMCID: PMC4309182 DOI: 10.3389/fmicb.2015.00009] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/05/2015] [Indexed: 11/13/2022] Open
Abstract
During the summer months, wet (hyporheic) soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DVs) become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here, we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~5 μg/cm3 for chlorophyll a, respectively). Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira, and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridiplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.
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Affiliation(s)
| | - Jill A Sohm
- Wrigley Institute for Environmental Studies and Department of Biological Sciences, University of Southern California Los Angeles, CA, USA
| | - Troy E Gunderson
- Wrigley Institute for Environmental Studies and Department of Biological Sciences, University of Southern California Los Angeles, CA, USA
| | - Alexander E Parker
- Romberg Tiburon Center for Environmental Studies, San Francisco State University Tiburon, CA, USA
| | - Joëlle Tirindelli
- Romberg Tiburon Center for Environmental Studies, San Francisco State University Tiburon, CA, USA
| | - Douglas G Capone
- Wrigley Institute for Environmental Studies and Department of Biological Sciences, University of Southern California Los Angeles, CA, USA
| | - Edward J Carpenter
- Romberg Tiburon Center for Environmental Studies, San Francisco State University Tiburon, CA, USA
| | - Stephen C Cary
- College of Marine and Earth Sciences, University of Delaware Lewes, DE, USA ; School of Science, University of Waikato Hamilton, New Zealand
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28
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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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29
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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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30
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Soil microbial responses to increased moisture and organic resources along a salinity gradient in a polar desert. Appl Environ Microbiol 2014; 80:3034-43. [PMID: 24610850 DOI: 10.1128/aem.03414-13] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Microbial communities in extreme environments often have low diversity and specialized physiologies suggesting a limited resistance to change. The McMurdo Dry Valleys (MDV) are a microbially dominated, extreme ecosystem currently undergoing climate change-induced disturbances, including the melting of massive buried ice, cutting through of permafrost by streams, and warming events. These processes are increasing moisture across the landscape, altering conditions for soil communities by mobilizing nutrients and salts and stimulating autotrophic carbon inputs to soils. The goal of this study was to determine the effects of resource addition (water/organic matter) on the composition and function of microbial communities in the MDV along a natural salinity gradient representing an additional gradient of stress in an already extreme environment. Soil respiration and the activity of carbon-acquiring extracellular enzymes increased significantly (P < 0.05) with the addition of resources at the low- and moderate-salinity sites but not the high-salinity site. The bacterial community composition was altered, with an increase in Proteobacteria and Firmicutes with water and organic matter additions at the low- and moderate-salinity sites and a near dominance of Firmicutes at the high-salinity site. Principal coordinate analyses of all samples using a phylogenetically informed distance matrix (UniFrac) demonstrated discrete clustering among sites (analysis of similarity [ANOSIM], P < 0.05 and R > 0.40) and among most treatments within sites. The results from this experimental work suggest that microbial communities in this environment will undergo rapid change in response to the altered resources resulting from climate change impacts occurring in this region.
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31
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The ecological role of moss in a polar desert: implications for aboveground–belowground and terrestrial–aquatic linkages. Polar Biol 2014. [DOI: 10.1007/s00300-014-1465-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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32
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Distribution and diversity of soil microfauna from East Antarctica: assessing the link between biotic and abiotic factors. PLoS One 2014; 9:e87529. [PMID: 24498126 PMCID: PMC3909186 DOI: 10.1371/journal.pone.0087529] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 12/27/2013] [Indexed: 11/19/2022] Open
Abstract
Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw), with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw). Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3− and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity.
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33
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Ball BA, Virginia RA. Microbial biomass and respiration responses to nitrogen fertilization in a polar desert. Polar Biol 2014. [DOI: 10.1007/s00300-014-1459-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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34
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Sokol ER, Herbold CW, Lee CK, Cary SC, Barrett JE. Local and regional influences over soil microbial metacommunities in the Transantarctic Mountains. Ecosphere 2013. [DOI: 10.1890/es13-00136.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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35
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Geyer KM, Altrichter AE, Van Horn DJ, Takacs-Vesbach CD, Gooseff MN, Barrett JE. Environmental controls over bacterial communities in polar desert soils. Ecosphere 2013. [DOI: 10.1890/es13-00048.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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36
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Factors Controlling Soil Microbial Biomass and Bacterial Diversity and Community Composition in a Cold Desert Ecosystem: Role of Geographic Scale. PLoS One 2013; 8:e66103. [PMID: 23824063 PMCID: PMC3688848 DOI: 10.1371/journal.pone.0066103] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 05/02/2013] [Indexed: 02/01/2023] Open
Abstract
Understanding controls over the distribution of soil bacteria is a fundamental step toward describing soil ecosystems, understanding their functional capabilities, and predicting their responses to environmental change. This study investigated the controls on the biomass, species richness, and community structure and composition of soil bacterial communities in the McMurdo Dry Valleys, Antarctica, at local and regional scales. The goals of the study were to describe the relationships between abiotic characteristics and soil bacteria in this unique, microbially dominated environment, and to test the scale dependence of these relationships in a low complexity ecosystem. Samples were collected from dry mineral soils associated with snow patches, which are a significant source of water in this desert environment, at six sites located in the major basins of the Taylor and Wright Valleys. Samples were analyzed for a suite of characteristics including soil moisture, pH, electrical conductivity, soil organic matter, major nutrients and ions, microbial biomass, 16 S rRNA gene richness, and bacterial community structure and composition. Snow patches created local biogeochemical gradients while inter-basin comparisons encompassed landscape scale gradients enabling comparisons of microbial controls at two distinct spatial scales. At the organic carbon rich, mesic, low elevation sites Acidobacteria and Actinobacteria were prevalent, while Firmicutes and Proteobacteria were dominant at the high elevation, low moisture and biomass sites. Microbial parameters were significantly related with soil water content and edaphic characteristics including soil pH, organic matter, and sulfate. However, the magnitude and even the direction of these relationships varied across basins and the application of mixed effects models revealed evidence of significant contextual effects at local and regional scales. The results highlight the importance of the geographic scale of sampling when determining the controls on soil microbial community characteristics.
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37
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O’Neill T, Balks M, Stevenson B, López-Martínez J, Aislabie J, Rhodes P. The short-term effects of surface soil disturbance on soil bacterial community structure at an experimental site near Scott Base, Antarctica. Polar Biol 2013. [DOI: 10.1007/s00300-013-1322-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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38
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LEE JENNIFERE, LE ROUX PETERC, MEIKLEJOHN KIAN, CHOWN STEVENL. Species distribution modelling in low-interaction environments: Insights from a terrestrial Antarctic system. AUSTRAL ECOL 2012. [DOI: 10.1111/j.1442-9993.2012.02401.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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39
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Nielsen UN, Wall DH, Adams BJ, Virginia RA, Ball BA, Gooseff MN, McKnight DM. The ecology of pulse events: insights from an extreme climatic event in a polar desert ecosystem. Ecosphere 2012. [DOI: 10.1890/es11-00325.1] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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40
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Lee CK, Barbier BA, Bottos EM, McDonald IR, Cary SC. The Inter-Valley Soil Comparative Survey: the ecology of Dry Valley edaphic microbial communities. ISME JOURNAL 2011; 6:1046-57. [PMID: 22170424 DOI: 10.1038/ismej.2011.170] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent applications of molecular genetics to edaphic microbial communities of the McMurdo Dry Valleys and elsewhere have rejected a long-held belief that Antarctic soils contain extremely limited microbial diversity. The Inter-Valley Soil Comparative Survey aims to elucidate the factors shaping these unique microbial communities and their biogeography by integrating molecular genetic approaches with biogeochemical analyses. Although the microbial communities of Dry Valley soils may be complex, there is little doubt that the ecosystem's food web is relatively simple, and evidence suggests that physicochemical conditions may have the dominant role in shaping microbial communities. To examine this hypothesis, bacterial communities from representative soil samples collected in four geographically disparate Dry Valleys were analyzed using molecular genetic tools, including pyrosequencing of 16S rRNA gene PCR amplicons. Results show that the four communities are structurally and phylogenetically distinct, and possess significantly different levels of diversity. Strikingly, only 2 of 214 phylotypes were found in all four valleys, challenging a widespread assumption that the microbiota of the Dry Valleys is composed of a few cosmopolitan species. Analysis of soil geochemical properties indicated that salt content, alongside altitude and Cu(2+), was significantly correlated with differences in microbial communities. Our results indicate that the microbial ecology of Dry Valley soils is highly localized and that physicochemical factors potentially have major roles in shaping the microbiology of ice-free areas of Antarctica. These findings hint at links between Dry Valley glacial geomorphology and microbial ecology, and raise previously unrecognized issues related to environmental management of this unique ecosystem.
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Affiliation(s)
- Charles K Lee
- Department of Biological Sciences, University of Waikato, Hamilton, New Zealand
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41
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Physical, chemical and microbial soil properties of frost boils at Browning Peninsula, Antarctica. Polar Biol 2011. [DOI: 10.1007/s00300-011-1076-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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42
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Experimentally increased snow accumulation alters soil moisture and animal community structure in a polar desert. Polar Biol 2010. [DOI: 10.1007/s00300-010-0766-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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43
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Cary SC, McDonald IR, Barrett JE, Cowan DA. On the rocks: the microbiology of Antarctic Dry Valley soils. Nat Rev Microbiol 2010; 8:129-38. [DOI: 10.1038/nrmicro2281] [Citation(s) in RCA: 414] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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45
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Landscape Distribution of Microbial Activity in the McMurdo Dry Valleys: Linked Biotic Processes, Hydrology, and Geochemistry in a Cold Desert Ecosystem. Ecosystems 2009. [DOI: 10.1007/s10021-009-9242-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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46
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Ayres E, Nkem JN, Wall DH, Adams BJ, Barrett JE, Broos EJ, Parsons AN, Powers LE, Simmons BL, Virginia RA. Effects of human trampling on populations of soil fauna in the McMurdo Dry Valleys, Antarctica. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2008; 22:1544-1551. [PMID: 18759772 DOI: 10.1111/j.1523-1739.2008.01034.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Antarctic ecosystems are often considered nearly pristine because levels of anthropogenic disturbance are extremely low there. Nevertheless, over recent decades there has been a rapid increase in the number of people, researchers and tourists, visiting Antarctica. We evaluated, over 10 years, the direct impact of foot traffic on the abundance of soil animals and soil properties in Taylor Valley within the McMurdo Dry Valleys region of Antarctica. We compared soils from minimally disturbed areas with soils from nearby paths that received intermediate and high levels of human foot traffic (i.e., up to approximately 80 passes per year). The nematodes Scottnema lindsayae and Eudorylaimus sp. were the most commonly found animal species, whereas rotifers and tardigrades were found only occasionally. On the highly trampled footpaths, abundance of S. lindsayae and Eudorylaimus sp. was up to 52 and 76% lower, respectively, than in untrampled areas. Moreover, reduction in S. lindsayae abundance was more pronounced after 10 years than 2 years and in the surface soil than in the deeper soil, presumably because of the longer period of disturbance and the greater level of physical disturbance experienced by the surface soil. The ratio of living to dead Eudorylaimus sp. also declined with increased trampling intensity, which is indicative of increased mortality or reduced fecundity. At one site there was evidence that high levels of trampling reduced soil CO(2) fluxes, which is related to total biological activity in the soil. Our results show that even low levels of human traffic can significantly affect soil biota in this ecosystem and may alter ecosystem processes, such as carbon cycling. Consequently, management and conservation plans for Antarctic soils should consider the high sensitivity of soil fauna to physical disturbance as human presence in this ecosystem increases.
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Affiliation(s)
- Edward Ayres
- Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, USA.
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47
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Niederberger TD, McDonald IR, Hacker AL, Soo RM, Barrett JE, Wall DH, Cary SC. Microbial community composition in soils of Northern Victoria Land, Antarctica. Environ Microbiol 2008; 10:1713-24. [PMID: 18373679 DOI: 10.1111/j.1462-2920.2008.01593.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Biotic communities and ecosystem dynamics in terrestrial Antarctica are limited by an array of extreme conditions including low temperatures, moisture and organic matter availability, high salinity, and a paucity of biodiversity to facilitate key ecological processes. Recent studies have discovered that the prokaryotic communities in these extreme systems are highly diverse with patchy distributions. Investigating the physical and biological controls over the distribution and activity of microbial biodiversity in Victoria Land is essential to understanding ecological functioning in this region. Currently, little information on the distribution, structure and activity of soil communities anywhere in Victoria Land are available, and their sensitivity to potential climate change remains largely unknown. We investigated soil microbial communities from low- and high-productivity habitats in an isolated Antarctic location to determine how the soil environment impacts microbial community composition and structure. The microbial communities in Luther Vale, Northern Victoria Land were analysed using bacterial 16S rRNA gene clone libraries and were related to soil geochemical parameters and classical morphological analysis of soil metazoan invertebrate communities. A total of 323 16S rRNA gene sequences analysed from four soils spanning a productivity gradient indicated a high diversity (Shannon-Weaver values > 3) of phylotypes within the clone libraries and distinct differences in community structure between the two soil productivity habitats linked to water and nutrient availability. In particular, members of the Deinococcus/Thermus lineage were found exclusively in the drier, low-productivity soils, while Gammaproteobacteria of the genus Xanthomonas were found exclusively in high-productivity soils. However, rarefaction curves indicated that these microbial habitats remain under-sampled. Our results add to the recent literature suggesting that there is a higher biodiversity within Antarctic soils than previously expected.
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48
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Species diversity and random distribution of microfauna in extremely isolated habitable patches on Antarctic nunataks. Polar Biol 2008. [DOI: 10.1007/s00300-008-0420-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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49
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Wall DH. Global change tipping points: above- and below-ground biotic interactions in a low diversity ecosystem. Philos Trans R Soc Lond B Biol Sci 2007; 362:2291-306. [PMID: 17553769 PMCID: PMC2443177 DOI: 10.1098/rstb.2006.1950] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Low diversity ecosystems are expected to be more vulnerable to global changes although they have received less attention than high diversity ecosystems. Addressing the present state of the Antarctic Dry Valley region by focusing on the potential global changes that may alter the coupling of above- and below-ground species and ecosystem processes is a realistic and critical need that has value beyond the Antarctic community. Presented here are suggested implications of global change on the Dry Valley terrestrial systems and how these effects might be manifested in the future.
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Affiliation(s)
- Diana H Wall
- Department of Biology and Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO 80523-1499, USA.
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50
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Warren-Rhodes KA, Dungan JL, Piatek J, Stubbs K, Gómez-Silva B, Chen Y, McKay CP. Ecology and spatial pattern of cyanobacterial community island patches in the Atacama Desert, Chile. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jg000305] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Jennifer Piatek
- Department of Earth and Planetary Sciences; University of Tennessee; Knoxville Tennessee USA
| | - Kristin Stubbs
- Robotics Institute; Carnegie Mellon University; Pittsburgh Pennsylvania USA
| | - Benito Gómez-Silva
- Departmento de Biomédico and Instituto del Desierto; Universidad de Antofagasta; Antofagasta Chile
| | - Yong Chen
- Department of Mechanical and Industrial Engineering; University of Iowa; Iowa City Iowa USA
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