%0 Journal Article %J Applied Soil Ecology %D 2024 %T An Antarctic worm and its soil ecosystem: A review of an emerging research program in ecological genomics %A Xue, Xia %A Thompson, Andrew R. %A Adams, Byron J. %K ecological amplitude %K ecological succession %K elemental stoichiometry %K extreme environments %K life history evolution %K model systems %X

Relationships between the evolution of species and their ecosystems can be difficult to accurately assess due to the high number of confounding biological variables (e.g., biotic interactions among community members and the resulting complex relationships between genetic pathways and organism phenotypes). Thus, progress in ecological genomics by making inferences about fundamental ecological patterns and processes is hampered by high biodiversity and subsequent complex biotic interactions. Study systems that are naturally low in biological and ecological complexity, and strongly structured by abiotic drivers, can serve as models for bridging the gap between controlled mesocosm experiments and natural ecosystems. The terrestrial ecosystems of the Antarctic dry valleys have low biodiversity and constrained ecological complexity, primarily because ecological communities are so strongly shaped by physical, rather than biological, factors. The harsh constraints of the physical environment on organismal evolution and the structure of ecological communities make this an optimal natural system for disentangling the influence of specific environmental parameters on genotype/phenotype and gene by environment interactions. This work reviews the biology, evolution, and ecology of an emerging model organism, the free-living nematode Plectus murrayi, in a model ecosystem, the McMurdo Dry Valleys (MDVs) of Antarctica. In the MDVs, habitat suitability, including nutrient availability, has been shown to drive organismal (nematode) life history evolution, including growth and reproduction, primarily by way of changes in the expression of developmental genes. Changes in growth rates and reproductive schedules are accomplished primarily through alterations of nuclear rRNA gene copy number. The predicted and observed responses to natural experiments have been replicated in the laboratory, providing a synthesis of field observations and experimental evolution. Studying such natural model systems as this could fill several persistent knowledge gaps in our understanding of how genetic variation, genomic architecture, and gene regulation drive the genotype-phenotype paradigm, and the consequent effects of these drivers on ecosystem structure and functioning.

%B Applied Soil Ecology %V 193 %P 105110 %8 01/2024 %G eng %U https://www.sciencedirect.com/science/article/pii/S0929139323003086 %R 10.1016/j.apsoil.2023.105110 %0 Journal Article %J Soil Biology and Biochemistry %D 2023 %T Ecological stoichiometry drives the evolution of soil nematode life history traits %A Xue, Xia %A Bishwo N. Adhikari %A Ball, Becky %A John E. Barrett %A Miao, Jinxin %A Perkes, Ammon %A Martin, Mac %A Breana L. Simmons %A Diana H. Wall %A Byron Adams %K elemental stoichiometry %K growth rate hypothesis %K life history theory %K molecular evolution %K nematoda %K rRNA %X

Ecological stoichiometry is a useful theoretical framework for understanding the sources and controls on nutrient availability that structure the composition and diversity of biotic communities. One such relationship is that organismal development rate is positively linked to cellular Phosphorus (P). We hypothesized that P availability, relative to other nutrients, e.g., nitrogen and carbon, would drive the evolution of traits associated with organismal growth and development. We examined the effects of P availability both in situ and in vitro, on free-living soil nematodes. We found that P-deficient environments produce predictable changes in the ecology and evolution of important life history traits. Our results identify altered rRNA gene copy number and subsequent changes in gene expression and protein synthesis as mechanisms by which P-deficiency influences these traits. These findings have important implications for explaining soil ecological and evolutionary patterns across multiple levels of organization, including the structure and functioning of organisms, populations, communities, and ecosystems.

%B Soil Biology and Biochemistry %V 177 %P 108891 %8 02/2023 %G eng %U https://www.sciencedirect.com/science/article/pii/S0038071722003480 %R 10.1016/j.soilbio.2022.108891 %0 Journal Article %J Science Advances %D 2023 %T Postglacial adaptations enabled colonization and quasi-clonal dispersal of ammonia-oxidizing archaea in modern European large lakes %A Ngugi, David Kamanda %A Salcher, Michaela M. %A Andrei, Adrian-Stefan %A Ghai, Rohit %A Klotz, Franziska %A Chiriac, Maria-Cecilia %A Ionescu, Danny %A Büsing, Petra %A Grossart, Hans-Peter %A Xing, Peng %A John C. Priscu %A Alymkulov, Salmor %A Pester, Michael %X

Ammonia-oxidizing archaea (AOA) play a key role in the aquatic nitrogen cycle. Their genetic diversity is viewed as the outcome of evolutionary processes that shaped ancestral transition from terrestrial to marine habitats. However, current genome-wide insights into AOA evolution rarely consider brackish and freshwater representatives or provide their divergence timeline in lacustrine systems. An unbiased global assessment of lacustrine AOA diversity is critical for understanding their origins, dispersal mechanisms, and ecosystem roles. Here, we leveraged continental-scale metagenomics to document that AOA species diversity in freshwater systems is remarkably low compared to marine environments. We show that the uncultured freshwater AOA, “Candidatus Nitrosopumilus limneticus,” is ubiquitous and genotypically static in various large European lakes where it evolved 13 million years ago. We find that extensive proteome remodeling was a key innovation for freshwater colonization of AOA. These findings reveal the genetic diversity and adaptive mechanisms of a keystone species that has survived clonally in lakes for millennia.

%B Science Advances %V 9 %P eadc9392 %8 02/2023 %G eng %U https://www.science.org/doi/10.1126/sciadv.adc9392 %N 5 %R 10.1126/sciadv.adc9392 %0 Journal Article %J Biology %D 2023 %T Temperature response of metabolic activity of an Antarctic nematode %A Robinson, Colin Michael %A Hansen, Lee D. %A Xue, Xia %A Adams, Byron J. %K Antarctica %K carbon cycling %K climate change %K nematode %K respiration rates %K soil temperature %X

Because of climate change, the McMurdo Dry Valleys of Antarctica (MCM) have experienced an increase in the frequency and magnitude of summer pulse warming and surface ice and snow melting events. In response to these environmental changes, some nematode species in the MCM have experienced steady population declines over the last three decades, but Plectus murrayi, a mesophilic nematode species, has responded with a steady increase in range and abundance. To determine how P. murrayi responds to increasing temperatures, we measured metabolic heat and CO2 production rates and calculated O2 consumption rates as a function of temperature at 5 °C intervals from 5 to 50 °C. Heat, CO2 production, and O2 consumption rates increase approximately exponentially up to 40 °C, a temperature never experienced in their polar habitat. Metabolic rates decline rapidly above 40 °C and are irreversibly lost at 50 °C due to thermal stress and mortality. Caenorhabditis elegans, a much more widespread nematode that is found in more temperate environments reaches peak metabolic heat rate at just 27 °C, above which it experiences high mortality due to thermal stress. At temperatures from 10 to 40 °C, P. murrayi produces about 6 times more CO2 than the O2 it consumes, a respiratory quotient indicative of either acetogenesis or de novo lipogenesis. No potential acetogenic microbes were identified in the P. murrayi microbiome, suggesting that P. murrayi is producing increased CO2 as a byproduct of de novo lipogenesis. This phenomenon, in conjunction with increased summer temperatures in their polar habitat, will likely lead to increased demand for carbon and subsequent increases in CO2 production, population abundance, and range expansion. If such changes are not concomitant with increased carbon inputs, we predict the MCM soil ecosystems will experience dramatic declines in functional and taxonomic diversity.

%B Biology %V 12 %P 109 %8 01/2023 %G eng %U https://www.mdpi.com/2079-7737/12/1/109 %N 1 %R 10.3390/biology12010109 %0 Journal Article %J Journal of Nematology %D 2022 %T A draft mitogenome of Plectus murrayi %A Xue, Xia %A Adams, Byron J. %A Dilman, Adler R. %K Antarctica %K genome decay %K genomics %K mitochondrial genome %K MitoZ %K phylogeny %X

Plectus murrayi is a free-living microbivorous nematode endemic to Antarctic soils. Our draft assembly of its mitogenome was 15,656 bp long, containing 12 protein-coding, eight transfer RNA (tRNA), and two ribosomal RNA (rRNA) genes. Mitophylogenomic analyses extend our understanding of mitochondrial evolution in Nematoda

%B Journal of Nematology %V 54 %8 02/2022 %G eng %U https://www.sciendo.com/article/10.2478/jofnem-2022-0035https://www.sciendo.com/pdf/10.2478/jofnem-2022-0035 %N 1 %R 10.2478/jofnem-2022-0035 %0 Report %D 2022 %T Ten scientific messages on risks and opportunities for life in the Antarctic %A Gutt, Julian %A Isla, Enrique %A Xavier, José C. %A Adams, Byron J. %A Ahn, In‐Young %A Cheng, C.‐H. Christina %A Colesie, Claudia %A Cummings, Vonda J. %A Griffiths, Huw J. %A Hogg, Ian D. %A McIntyre, Trevor %A Meiners, Klaus M. %A Pearce, David A. %A Lloyd S. Peck %A Piepenburg, Dieter %A Reisinger, Ryan R. %A Saba, Grace %A Schloss, Irene R. %A Signori, Camila N. %A Smith, Craig R. %A Vacchi, Marino %A Verde, Cinzia %A Diana H. Wall %X

Initiated by the SCAR scientific research programme “Antarctic Thresholds – Ecosystem Resilience and Adaptation” (AnT-ERA, 2013-2021), 26 experts synthesized knowledge on impacts and risks of climate-change on biological processes and ecosystem functions in the Antarctic. The ten main scientific messages that emerged addressed (1) accelerating marine and terrestrial biogeochemical cycles, (2) response to ocean acidification, (3) ecological changes in climate change hot spots, (4) unexpected dynamism of marine seafloor communities, (5) biodiversity shifts, (6) low temperature limitation of protein synthesis, (7) life intrinsically linked to changing sea ice conditions, (8) pollution, (9) genetically distinct terrestrial populations under threat, and (10) newly discovered habitats. Two-thirds of the literature included in this synthesis was published between 2010 and 2020 and only one-third was published earlier. The fast mounting, recent decadal evidence indicates various Antarctic biological communities now experience climate stress, or will experience such stress in the coming decades. The responses of organisms, ecosystem functions and services to environmental changes are complex and varied. Key knowledge gaps remain and need addressing to adequately assess future prospects for life in the Antarctic.

%B Information Summaries %I Antarctic Environments Portal %8 02/2022 %G eng %U https://environments.aq/publications/ten-scientific-messages-on-risks-and-opportunities-for-life-in-the-antarctic/ %0 Journal Article %J Biological Reviews %D 2021 %T Antarctic ecosystems in transition – life between stresses and opportunities %A Gutt, Julian %A Isla, Enrique %A Xavier, José C. %A Adams, Byron J. %A Ahn, In‐Young %A Cheng, C.‐H. Christina %A Colesie, Claudia %A Cummings, Vonda J. %A di Prisco, Guido %A Griffiths, Huw J. %A Ian Hawes %A Hogg, Ian D. %A McIntyre, Trevor %A Meiners, Klaus M. %A Pearce, David A. %A Lloyd S. Peck %A Piepenburg, Dieter %A Reisinger, Ryan R. %A Saba, Grace %A Schloss, Irene R. %A Signori, Camila N. %A Smith, Craig R. %A Vacchi, Marino %A Verde, Cinzia %A Diana H. Wall %K adaptation %K benthic dynamism %K biogeochemical cycles %K climate change %K invasion %K new habitats %K ocean acidification %K Primary production %K range shifts %K sea ice %X

Important findings from the second decade of the 21st century on the impact of environmental change on biological processes in the Antarctic were synthesised by 26 international experts. Ten key messages emerged that have stakeholder‐relevance and/or a high impact for the scientific community. They address (i) altered biogeochemical cycles, (ii) ocean acidification, (iii) climate change hotspots, (iv) unexpected dynamism in seabed‐dwelling populations, (v) spatial range shifts, (vi) adaptation and thermal resilience, (vii) sea ice related biological fluctuations, (viii) pollution, (ix) endangered terrestrial endemism and (x) the discovery of unknown habitats. Most Antarctic biotas are exposed to multiple stresses and considered vulnerable to environmental change due to narrow tolerance ranges, rapid change, projected circumpolar impacts, low potential for timely genetic adaptation, and migration barriers. Important ecosystem functions, such as primary production and energy transfer between trophic levels, have already changed, and biodiversity patterns have shifted. A confidence assessment of the degree of ‘scientific understanding’ revealed an intermediate level for most of the more detailed sub‐messages, indicating that process‐oriented research has been successful in the past decade. Additional efforts are necessary, however, to achieve the level of robustness in scientific knowledge that is required to inform protection measures of the unique Antarctic terrestrial and marine ecosystems, and their contributions to global biodiversity and ecosystem services.

%B Biological Reviews %8 06/2021 %G eng %U https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12679 %R 10.1111/brv.12679 %0 Journal Article %J G3 Genes|Genomes|Genetics %D 2021 %T Genome analysis of Plectus murrayi, a nematode from continental Antarctica %A Xue, Xia %A Suvorov, Anton %A Fujimoto, Stanley %A Dilman, Adler R. %A Byron Adams %K gene loss %K genome architecture %K genome assembly %K genome decay %K Plectus murrayi %X

Plectus murrayi is one of the most common and locally abundant invertebrates of continental Antarctic ecosystems. Because it is readily cultured on artificial medium in the laboratory and highly tolerant to an extremely harsh environment, Plectus murrayi is emerging as a model organism for understanding the evolutionary origin and maintenance of adaptive responses to multiple environmental stressors, including freezing and desiccation. The de novo assembled genome of Plectus murrayi contains 225.741 million base pairs and a total of 14,689 predicted genes. Compared to Caenorhabditis elegans, the architectural components of Plectus murrayi are characterized by a lower number of protein-coding genes, fewer transposable elements, but more exons, than closely related taxa from less harsh environments. We compared the transcriptomes of lab-reared Plectus murrayi with wild-caught Plectus murrayi and found genes involved in growth and cellular processing were up-regulated in lab-cultured Plectus murrayi, while a few genes associated with cellular metabolism and freeze tolerance were expressed at relatively lower levels. Preliminary comparative genomic and transcriptomic analyses suggest that the observed constraints on P. murrayi genome architecture and functional gene expression, including genome decay and intron retention, may be an adaptive response to persisting in a biotically simplified, yet consistently physically harsh environment.

%B G3 Genes|Genomes|Genetics %8 01/2021 %G eng %U https://academic.oup.com/g3journal/advance-article/doi/10.1093/g3journal/jkaa045/6044189 %R 10.1093/g3journal/jkaa045 %0 Thesis %B Department of Biology %D 2018 %T Genomics and transcriptomics of Antarctic nematodes reveal drivers of life history evolution and genome evolution %A Xue, Xia %A Byron Adams %K Antarctic nematodes %K Caenorhabditis elegans %K genome evolution %K growth rate hypothesis %K Plectus murrayi %K Scottnema lindsayae %K transcriptome %X

Elemental stoichiometry defines a critical understanding of the relationship between nutrient availability and usage throughout different levels of the biological community. We found there is a link between available phosphorus (P), cellular phosphorus, and nematode development as postulated by the growth rate hypothesis (GRH). I predicted that in a P-poor environment, cellular RNA concentrations would be lower than they are in P-rich environment, and thus the 18srRNA expression level will have reduced. To most efficiently regulate the uptake of limited P, I predicted that nematodes in P-poor environments would decrease the number of copies of the 18s rRNA gene in their genome. I measured life history traits as well as rRNA gene expression and gene copy number. We found that elemental stoichiometry predicts evolutionary changes consistent with the Growth Rate Hypothesis. We sequenced and assembled a draft genome of P. murrayi. Although we expected to find genes responsible for stress tolerance, we hypothesized that in response to strong selection pressure associated with living in a simplified ecosystem, over time the genome of P. murrayi should have undergone significant decay (gene loss) relative to species in ecosystems structured more strongly by biotic interactions. We found significantly fewer genes in P. murrayi. To compare patterns of gene expression between two highly divergent Antarctic nematode species, we sequenced and assembled the transcriptomes of S. lindsayae and P. murrayi. Under laboratory conditions at 4  ̊C, S. lindsayae had significantly lower rates of gene expression but expressed a significantly larger number of genes. We speculate that the differences in gene expression are correlated with life history traits (developmental rates) while the differences in the number of genes expressed can be explained by their different genetic systems (S. lindsayae is amphimictic, P. murrayi is parthenogenic) and the soil environments to which they are adapted. Since we previously showed that differences in available P content can influence the evolution of gene expression via gene copy number, and that this ultimately influences growth rate, we wondered how much of this response is driven by genetics versus how strongly these patterns are driven by temperature. To better understand this, we maintained wild type populations of P. murrayi in P-rich and P-poor conditions at 5  ̊C, 10  ̊C and 15 ̊C in the laboratory for over 40 generations and sequenced the transcriptomes prepared from each treatment group. We found that nutrient levels played an important role in gene expression when the temperature is optimal for P. murrayi culturing and that temperature is more important in gene expression when the available P is limited. This work underscores the utility of using principles of elemental stoichiometry coupled with genomic and transcriptomics research tools to make and test predictions about life history evolution. The results of my work also inform inferences about the ways in which nutrient availability also drives the organization of trophic interactions and ultimately ecosystems.

%B Department of Biology %I Brigham Young University %C Provo, UT %V Ph.D. %G eng %U https://search.proquest.com/docview/2081899003 %9 doctoral %0 Journal Article %J Journal of Geophysical Research: Atmospheres %D 2018 %T Near-surface refractory black carbon observations in the atmosphere and snow in the McMurdo Dry Valleys, Antarctica and potential impacts of foehn winds %A Khan, Alia L. %A McMeeking, Gavin %A Schwarz, Joshua P. %A Xian, Peng %A Kathleen A. Welch %A W. Berry Lyons %A Diane M. McKnight %X

Measurements of light absorbing particles in the boundary layer of the high southern latitudes are scarce, particularly in the McMurdo Dry Valleys (MDV), Antarctica. During the 2013 - 2014 austral summer near-surface boundary layer refractory black carbon (rBC) aerosols were measured in air by a single particle soot photometer (SP2) at multiple locations in the MDV. Near-continuous rBC atmospheric measurements were collected at Lake Hoare Camp (LH) over two months and for several hours at more remote locations away from established field camps. We investigated periods dominated by both up and down-valley winds to explore the causes of differences in rBC concentrations and size distributions. Snow samples were also collected in a 1m pit on a glacier near the camp. The range of concentrations rBC in snow were 0.3 1.2 ± 0.3 μg-rBC/L-H2O, and total organic carbon were 0.3 1.4 ± 0.3 mg/L. The rBC concentrations measured in this snow pit are not sufficient to reduce surface albedo, however, there is potential for accumulation of rBC on snow and ice surfaces at low elevation throughout the MDV which were not measured as part of this study. At LH, the average background rBC mass aerosol concentrations was 1.3 ng/m3. rBC aerosol mass concentrations were slightly lower, 0.09 1.3 ng/m3, at the most remote sites in the MDV. Concentration spikes as high as 200 ng/m3 were observed at LH, associated with local activities. During a foehn wind event, the average rBC mass concentration increased to 30-50 ng m-3. Here we show the rBC increase could be due to resuspension of locally produced BC from generators, rocket toilets, and helicopters, which may remain on the soil surface until redistributed during high wind events. Quantification of local production and long-range atmospheric transport of rBC to the MDV is necessary for understanding the impacts of this species on regional climate. 

 

%B Journal of Geophysical Research: Atmospheres %V 123 %P 2877 - 2887 %8 01/2018 %G eng %U http://doi.wiley.com/10.1002/2017JD027696 %N 5 %! J. Geophys. Res. Atmos. %R 10.1002/2017JD027696 %0 Journal Article %J Nature %D 2017 %T A communal catalogue reveals Earth’s multiscale microbial diversity %A Thompson, Luke R. %A Sanders, Jon G. %A McDonald, Daniel %A Amir, Amnon %A Ladau, Joshua %A Locey, Kenneth J. %A Prill, Robert J. %A Tripathi, Anupriya %A Gibbons, Sean M. %A Ackermann, Gail %A Navas-Molina, Jose A. %A Janssen, Stefan %A Kopylova, Evguenia %A Vázquez-Baeza, Yoshiki %A Antonio González %A Morton, James T. %A Mirarab, Siavash %A Zech Xu, Zhenjiang %A Jiang, Lingjing %A Haroon, Mohamed F. %A Kanbar, Jad %A Zhu, Qiyun %A Jin Song, Se %A Kosciolek, Tomasz %A Bokulich, Nicholas A. %A Lefler, Joshua %A Brislawn, Colin J. %A Humphrey, Gregory %A Owens, Sarah M. %A Hampton-Marcell, Jarrad %A Berg-Lyons, Donna %A McKenzie, Valerie %A Noah Fierer %A Fuhrman, Jed A. %A Clauset, Aaron %A Stevens, Rick L. %A Shade, Ashley %A Pollard, Katherine S. %A Goodwin, Kelly D. %A Jansson, Janet K. %A Gilbert, Jack A. %A Knight, Rob %A The Earth Microbiome Project Consortium %X

Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity.

%B Nature %V 551 %8 11/2017 %G eng %U https://www.nature.com/articles/nature24621 %& 457 %R 10.1038/nature24621 %0 Journal Article %J Geophysical Research Letters %D 2017 %T Dissolved black carbon in the global cryosphere: Concentrations and chemical signatures %A Khan, Alia L. %A Wagner, Sasha %A Jaffé, Rudolf %A Xian, Peng %A Williams, Mark %A Armstrong, Richard %A Diane M. McKnight %X

Black carbon (BC) is derived from the incomplete combustion of biomass and fossil fuels and can enhance glacial recession when deposited on snow and ice surfaces. Here we explore the influence of environmental conditions and the proximity to anthropogenic sources on the concentration and composition of dissolved black carbon (DBC), as measured by benzenepolycaroxylic acid (BPCA) markers, across snow, lakes, and streams from the global cryosphere. Data are presented from Antarctica, the Arctic, and high alpine regions of the Himalayas, Rockies, Andes, and Alps. DBC concentrations spanned from 0.62 μg/L to 170 μg/L. The median and (2.5, 97.5) quantiles in the pristine samples were 1.8 μg/L (0.62, 12), and nonpristine samples were 21 μg/L (1.6, 170). DBC is susceptible to photodegradation when exposed to solar radiation. This process leads to a less condensed BPCA signature. In general, DBC across the data set was composed of less polycondensed DBC. However, DBC from the Greenland Ice Sheet (GRIS) had a highly condensed BPCA molecular signature. This could be due to recent deposition of BC from Canadian wildfires. Variation in DBC appears to be driven by a combination of photochemical processing and the source combustion conditions under which the DBC was formed. Overall, DBC was found to persist across the global cryosphere in both pristine and nonpristine snow and surface waters. The high concentration of DBC measured in supraglacial melt on the GRIS suggests that DBC can be mobilized across ice surfaces. This is significant because these processes may jointly exacerbate surface albedo reduction in the cryosphere. 

%B Geophysical Research Letters %V 44 %P 6226-6234 %8 06/2017 %G eng %U http://doi.wiley.com/10.1002/2017GL073485 %N 12 %! Geophys. Res. Lett. %R 10.1002/2017GL073485 %0 Journal Article %J Antarctic Science %D 2015 %T A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond %A Kennicutt, M.C. %A Steven L. Chown %A Cassano, J.J. %A Liggett, D. %A Lloyd S. Peck %A Massom, R. %A Rintoul, S.R. %A Storey, J. %A Vaughan, D.G. %A Wilson, T.J. %A Allison, I. %A Ayton, J. %A Badhe, R. %A Baeseman, J. %A Barrett, P.J. %A Elanor R. Bell %A Bertler, N. %A Bo, S. %A Brandt, A. %A David Bromwich %A Craig S Cary %A Clark, M.S. %A Peter Convey %A Costa, E.S. %A Cowan, D. %A Deconto, R. %A Dunbar, R. %A Elfring, C. %A Escutia, C. %A Francis, J. %A Fricker, H.A. %A Fukuchi, M. %A Gilbert, N. %A Gutt, J. %A Havermans, C. %A Hik, D. %A Hosie, G. %A Jones, C. %A Kim, Y.D. %A Le Maho, Y. %A Lee, S.H. %A Leppe, M. %A Leitchenkov, G. %A Li, X. %A Lipenkov, V. %A Lochte, K. %A López-Martínez, J. %A üdecke, C. %A W. Berry Lyons %A Marenssi, S. %A Miller, H. %A Morozova, P. %A Naish, T. %A Nayak, S. %A Ravindra, R. %A Retamales, J. %A Ricci, C.A. %A Rogan-Finnemore, M. %A Ropert-Coudert, Y. %A Samah, A.A. %A Sanson, L. %A Scambos, T. %A I.R. Schloss %A Shiraishi, K. %A Siegert, M.J. %A Simões, J.C. %A Storey, B. %A Sparrow, M.D. %A Diana H. Wall %A Walsh, J.C. %A Wilson, G. %A Winther, J.G. %A J.C. Xavier %A Yang, H. %A Sutherland, W.J. %X

Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone

%B Antarctic Science %V 27 %P 3 - 18 %8 Jan-02-2015 %G eng %U http://www.journals.cambridge.org/abstract_S0954102014000674 %N 01 %! Antarctic Science %R 10.1017/S0954102014000674 %0 Journal Article %J Polarforschung %D 2013 %T Antarctic Thresholds - Ecosystem Resilience and Adaptation (AnT-ERA), a new SCAR-biology programme %A Gutt, J. %A Byron Adams %A T Bracegirdle %A Cowan, D. %A Vonda Cummings %A di Prisco, G. %A Gradinger, R. %A Isla, E. %A McIntyre, T. %A Murphy, E %A Lloyd S. Peck %A I.R. Schloss %A Smith, C. %A Suckling, C. C. %A Takahashi, A. %A Diana H. Wall %A J.C. Xavier %X

Stresses on Antarctic ecosystems result from environmental change, including extreme events, and from (other) human impacts. Consequently, Antarctic habitats are changing, some at a rapid pace while others are relatively stable. A cascade of responses from molecular through organismic to the community level are expected. The differences in biological complexity and evolutionary histories between both polar regions and the rest of the planet suggest that stresses on polar ecosystem function may have fundamentally different outcomes from those at lower latitudes. Polar ecosystem processes are therefore key to informing wider ecological debate about the nature of stability and potential changes across the biosphere. The main goal of AnT-ERA is to facilitate the science required to examine changes in biological processes in Antarctic and sub-Antarctic marine-, freshwater and terrestrial ecosystems. Tolerance limits, as well as thresholds, resistance and resilience to environmental change will be determined. AnT-ERA is classified into three overlapping themes, which represent three levels of biological organisation: (1) molecular and physiological performance, (2) population processes and species traits, (3) ecosystem function and services.

%B Polarforschung %V 82 %P 147-150. %8 10/2013 %G eng %U http://epic.awi.de/34238/1/Polarforschung_82-2_147-150.pdf %& 147 %0 Journal Article %J Review of Geophysics %D 2009 %T State of the Antarctic and the Southern Ocean climate system, %A Paul A. Mayewski %A David Bromwich %A Campbell, H %A Hamilton, G %A W. Berry Lyons %A Maasch, K %A Aoki, S %A Xiao, C %A van Ommen, T %A Meredith, M %A Summerhayes, C %A Turner, J %A Worby, A %A John E. Barrett %A Casassa, G %A Bertler, N %A T Bracegirdle %B Review of Geophysics %V 47 %G eng %R LTER