%0 Journal Article %J Science of Remote Sensing %D 2024 %T Remotely characterizing photosynthetic biocrust in snowpack-fed microhabitats of Taylor Valley, Antarctica %A Power, Sarah N. %A Salvatore, Mark R. %A Eric R. Sokol %A Lee F. Stanish %A Borges, Schuyler R. %A Byron Adams %A John E. Barrett %K Antarctica %K biocrust %K carbon %K reflectance spectroscopy %K snow %K soil ecology %X

Microbial communities are the primary drivers of carbon cycling in the McMurdo Dry Valleys of Antarctica. Dense microbial mats, consisting mainly of photosynthetic cyanobacteria, occupy aquatic areas associated with streams and lakes. Other microbial communities also occur at lower densities as patchy surface biological soil crusts (hereafter, biocrusts) across the terrestrial landscape. Multispectral satellite data have been used to model microbial mat abundance in high-density areas like stream and lake margins, but no previous studies have investigated the lower detection limits of biocrusts. Here, we describe remote sensing and field-based survey and sampling approaches to study the detectability and distribution of biocrusts in the McMurdo Dry Valleys. Using a combination of multi- and hyperspectral tools and spectral linear unmixing, we modeled the abundances of biocrust in eastern Taylor Valley. Our spectral approaches can detect low masses of biocrust material in laboratory microcosms down to biocrust concentrations of 1% by mass. These techniques also distinguish the spectra of biocrust from both surface rock and mineral signatures from orbit. We found that biocrusts are present throughout the soils of eastern Taylor Valley and are associated with diverse underlying soil communities. The densest biocrust communities identified in this study had total organic carbon 5x greater than the content of typical arid soils. The most productive biocrusts were located downslope of melting snowpacks in unique soil ecosystems that are distinct from the surrounding arid landscape. There are similarities between the snowpack and stream sediment communities (high diversity of soil invertebrates) as well as their ecosystem properties (e.g., persistence of liquid water, high transfer of available nutrients, lower salinity from flushing) compared to the typical arid terrestrial ecosystem of the dry valleys. Our approach extends the capability of orbital remote sensing of photosynthetic communities out of the aquatic margins and into the drier soils which comprise most of this landscape. This interdisciplinary work is critical for measuring and monitoring terrestrial carbon stocks and predicting future ecosystem dynamics in this currently water-limited but increasingly dynamic Antarctic landscape, which is particularly climate-sensitive and difficult to access.

%B Science of Remote Sensing %P 100120 %8 02/2024 %G eng %U https://www.sciencedirect.com/science/article/pii/S266601722400004X %R 10.1016/j.srs.2024.100120 %0 Journal Article %J Genes %D 2023 %T Biogeography and genetic diversity of terrestrial mites in the Ross Sea region, Antarctica %A Gemma E. Collins %A Young, Monica R. %A Peter Convey %A Steven L. Chown %A Craig S Cary %A Byron Adams %A Diana H. Wall %A Hogg, Ian D. %K Acari %K Antarctic conservation %K DNA barcoding %K geographic isolation %K speciation %X

Free-living terrestrial mites (Acari) have persisted through numerous glacial cycles in Antarctica. Very little is known, however, of their genetic diversity and distribution, particularly within the Ross Sea region. To redress this gap, we sampled mites throughout the Ross Sea region, East Antarctica, including Victoria Land and the Queen Maud Mountains (QMM), covering a latitudinal range of 72–85 °S, as well as Lauft Island near Mt. Siple (73 °S) in West Antarctica and Macquarie Island (54 °S) in the sub-Antarctic. We assessed genetic diversity using mitochondrial cytochrome c oxidase subunit I gene sequences (COI-5P DNA barcode region), and also morphologically identified voucher specimens. We obtained 130 sequences representing four genera: Nanorchestes (n = 30 sequences), Stereotydeus (n = 46), Coccorhagidia (n = 18) and Eupodes (n = 36). Tree-based analyses (maximum likelihood) revealed 13 genetic clusters, representing as many as 23 putative species indicated by barcode index numbers (BINs) from the Barcode of Life Datasystems (BOLD) database. We found evidence for geographically-isolated cryptic species, e.g., within Stereotydeus belli and S. punctatus, as well as unique genetic groups occurring in sympatry (e.g., Nanorchestes spp. in QMM). Collectively, these data confirm high genetic divergence as a consequence of geographic isolation over evolutionary timescales. From a conservation perspective, additional targeted sampling of understudied areas in the Ross Sea region should be prioritised, as further diversity is likely to be found in these short-range endemic mites.

%B Genes %V 14 %P 606 %8 03/2023 %G eng %U https://www.mdpi.com/2073-4425/14/3/606 %N 3 %R 10.3390/genes14030606 %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 Global Change Biology %D 2022 %T Community assembly in the wake of glacial retreat: A meta‐analysis %A Pothula, Satyendra K. %A Byron Adams %K chronosequence %K climate change %K community assembly %K deglaciation %K ecological succession %K glacial forefields %K soil ecosystems %X

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.

%B Global Change Biology %8 09/2022 %G eng %U https://onlinelibrary.wiley.com/doi/10.1111/gcb.16427 %R 10.1111/gcb.16427 %0 Journal Article %J mSystems %D 2022 %T Elevational constraints on the composition and genomic attributes of microbial communities in Antarctic soils %A Dragone, Nicholas B. %A Henley, Jessica B. %A Holland-Moritz, Hannah %A Melisa A. Diaz %A Hogg, Ian D. %A W. Berry Lyons %A Diana H. Wall %A Byron Adams %A Noah Fierer %E Mackelprang, Rachel %K Antarctica %K microbial ecology %K soil microbiology %K soils %X

The inland soils found on the Antarctic continent represent one of the more challenging environments for microbial life on Earth. Nevertheless, Antarctic soils harbor unique bacterial and archaeal (prokaryotic) communities able to cope with extremely cold and dry conditions. These communities are not homogeneous, and the taxonomic composition and functional capabilities (genomic attributes) of these communities across environmental gradients remain largely undetermined. We analyzed the prokaryotic communities in soil samples collected from across the Shackleton Glacier region of Antarctica by coupling quantitative PCR, marker gene amplicon sequencing, and shotgun metagenomic sequencing. We found that elevation was the dominant factor explaining differences in the structures of the soil prokaryotic communities, with the drier and saltier soils found at higher elevations harboring less diverse communities and unique assemblages of cooccurring taxa. The higher-elevation soil communities also had lower maximum potential growth rates (as inferred from metagenome-based estimates of codon usage bias) and an overrepresentation of genes associated with trace gas metabolism. Together, these results highlight the utility of assessing community shifts across pronounced environmental gradients to improve our understanding of the microbial diversity found in Antarctic soils and the strategies used by soil microbes to persist at the limits of habitability.

%B mSystems %V 7 %P e01330-21 %8 01/2022 %G eng %U https://journals.asm.org/doi/full/10.1128/msystems.01330-21 %N 1 %R 10.1128/msystems.01330-21 %0 Journal Article %J Global Change Biology %D 2022 %T Response of Antarctic soil fauna to climate‐driven changes since the Last Glacial Maximum %A Franco, André L. C. %A Byron Adams %A Melisa A. Diaz %A Lemoine, Nathan P. %A Dragone, Nicholas B. %A Noah Fierer %A W. Berry Lyons %A Hogg, Ian D. %A Diana H. Wall %K biodiversity %K climate change %K glacial retreat %K nematodes %K Shackleton Glacier %K soil invertebrates %X

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 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.

%B Global Change Biology %V 28 %8 01/2022 %G eng %U https://onlinelibrary.wiley.com/doi/10.1111/gcb.15940 %N 2 %R 10.1111/gcb.15940 %0 Journal Article %J Proceedings of the National Academy of Sciences %D 2022 %T The time is right for an Antarctic biorepository network %A O’Brien, Kristin M. %A Crockett, Elizabeth L. %A Byron Adams %A Amsler, Charles D. %A Appiah-Madson, Hannah J. %A Collins, Allen %A Desvignes, Thomas %A Detrich, H. William %A Distel, Daniel L. %A Eppley, Sarah M. %A Frable, Benjamin W. %A Franz, Nico M. %A Grim, Jeffrey M. %A Kocot, Kevin M. %A Mahon, Andrew R. %A Mayfield-Meyer, Teresa J. %A Jill A. Mikucki %A Moser, William E. %A Schmull, Michaela %A Seid, Charlotte A. %A Smith, Craig R. %A Todgham, Anne E. %A Watkins-Colwell, Gregory J. %X

Antarctica is a central driver of the Earth’s climate and health. The Southern Ocean surrounding Antarctica serves as a major sink for anthropogenic CO2 and heat, and the loss of Antarctic ice sheets contributes significantly to sea level rise and will continue to do so as the loss of ice sheets accelerates, with sufficient water stores to raise sea levels by 58 m. Antarctica's marine environment is home to a number of iconic species, and the terrestrial realm harbors a remarkable oasis for life, much of which has yet to be discovered. Distinctive oceanographic features of the Southern Ocean—including the Antarctic Circumpolar Current, the Antarctic Polar Front, and exceptional depths surrounding the continent—coupled with chronically cold temperatures have fostered the evolution of a vast number of uniquely coldadapted species, many of which are found nowhere else on the Earth. The Antarctic marine biota, for example, displays the highest level of species endemism on the Earth. However, warming, ocean acidification, pollution, and commercial exploitation threaten the integrity of Antarctic ecosystems. Understanding changes in the biota and its capacities for adaptation is imperative for establishing effective policies for mitigating the impacts of climate change and sustaining the Antarctic ecosystems that are vital to global health.

%B Proceedings of the National Academy of Sciences %V 119 %8 12/2022 %G eng %U https://www.pnas.org/doi/10.1073/pnas.2212800119 %N 50 %! Proc. Natl. Acad. Sci. U.S.A. %R 10.1073/pnas.2212800119 %0 Journal Article %J Frontiers in Microbiology %D 2021 %T Antarctic water tracks: Microbial community responses to variation in soil moisture, pH, and salinity %A George, Scott F. %A Noah Fierer %A Joseph S. Levy %A Byron Adams %K Antarctica %K extremophiles %K Mars analog %K microbial ecology %K water tracks %X

Ice-free soils in the McMurdo Dry Valleys select for taxa able to cope with challenging environmental conditions, including extreme chemical water activity gradients, freeze-thaw cycling, desiccation, and solar radiation regimes. The low biotic complexity of Dry Valley soils makes them well suited to investigate environmental and spatial influences on bacterial community structure. Water tracks are annually wetted habitats in the cold-arid soils of Antarctica that form briefly each summer with moisture sourced from snow melt, ground ice thaw, and atmospheric deposition via deliquescence and vapor flow into brines. Compared to neighboring arid soils, water tracks are highly saline and relatively moist habitats. They represent a considerable area (∼5–10 km2) of the Dry Valley terrestrial ecosystem, an area that is expected to increase with ongoing climate change. The goal of this study was to determine how variation in the environmental conditions of water tracks influences the composition and diversity of microbial communities. We found significant differences in microbial community composition between on- and off-water track samples, and across two distinct locations. Of the tested environmental variables, soil salinity was the best predictor of community composition, with members of the Bacteroidetes phylum being relatively more abundant at higher salinities and the Actinobacteria phylum showing the opposite pattern. There was also a significant, inverse relationship between salinity and bacterial diversity. Our results suggest water track formation significantly alters dry soil microbial communities, likely influencing subsequent ecosystem functioning. We highlight how Dry Valley water tracks could be a useful model system for understanding the potential habitability of transiently wetted environments found on the surface of Mars.

%B Frontiers in Microbiology %V 12 %8 01/2021 %G eng %U https://www.frontiersin.org/articles/10.3389/fmicb.2021.616730 %! Front. Microbiol. %R 10.3389/fmicb.2021.616730 %0 Journal Article %J Ecosphere %D 2021 %T Connectivity: Insights from the U.S. Long Term Ecological Research Network %A Iwaniec, David M. %A Michael N. Gooseff %A Suding, Katharine N. %A Johnson, David Samuel %A Reed, Daniel C. %A Debra P. C. Peters %A Byron Adams %A John E. Barrett %A Bestelmeyer, Brandon T. %A Castorani, Max C. N. %A Cook, Elizabeth M. %A Davidson, Melissa J. %A Groffman, Peter M. %A Hanan, Niall P. %A Huenneke, L %A Johnson, Pieter T. J. %A Diane M. McKnight %A Miller, Robert J. %A Okin, Gregory S. %A Preston, Daniel L. %A Rassweiler, Andrew %A Ray, Chris %A Osvaldo E. Sala %A Schooley, Robert %A Seastedt, Timothy %A Spasojevic, Marko J. %A Vivoni, Enrique R. %K alpine tundra %K Antarctic polar desert %K arid grassland %K arid shrubland %K coastal %K estuary %K salt marsh %K Special Feature: Forecasting Earth’s Ecosystems with Long-Term Ecological Research %K urban ecosystem %X

Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation-funded Long-Term Ecological Research (LTER) network addressing the core research area of “populations and communities.” The objective of this effort was to show the importance of long-term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case study about what their site could look like in 50–100 yr as human and environmental drivers influencing specific ecosystems change. As the case studies were prepared, five themes emerged, and the studies were grouped into papers in this LTER Futures Special Feature addressing state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the “connectivity” theme and has examples from the Phoenix (urban), Niwot Ridge (alpine tundra), McMurdo Dry Valleys (polar desert), Plum Island (coastal), Santa Barbara Coastal (coastal), and Jornada (arid grassland and shrubland) sites. Connectivity has multiple dimensions, ranging from multi-scalar interactions in space to complex interactions over time that govern the transport of materials and the distribution and movement of organisms. The case studies presented here range widely, showing how land-use legacies interact with climate to alter the structure and function of arid ecosystems and flows of resources and organisms in Antarctic polar desert, alpine, urban, and coastal marine ecosystems. Long-term ecological research demonstrates that connectivity can, in some circumstances, sustain valuable ecosystem functions, such as the persistence of foundation species and their associated biodiversity or, it can be an agent of state change, as when it increases wind and water erosion. Increased connectivity due to warming can also lead to species range expansions or contractions and the introduction of undesirable species. Continued long-term studies are essential for addressing the complexities of connectivity. The diversity of ecosystems within the LTER network is a strong platform for these studies.

%B Ecosphere %V 12 %P e03432 %8 05/2021 %G eng %U https://onlinelibrary.wiley.com/doi/10.1002/ecs2.3432 %N 5 %R 10.1002/ecs2.v12.510.1002/ecs2.3432 %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 Journal Article %J Proceedings of the National Academy of Sciences %D 2020 %T Genetic diversity of soil invertebrates corroborates timing estimates for past collapses of the West Antarctic Ice Sheet %A Gemma E. Collins %A Hogg, Ian D. %A Convey, Peter %A Sancho, Leopoldo G. %A Cowan, Don A. %A W. Berry Lyons %A Byron Adams %A Diana H. Wall %A Allan Green, T. G. %K climate change %K microarthropods %K molecular clock %K phylogeography %K terrestrial biodiversity %X

During austral summer field seasons between 1999 and 2018, we sampled at 91 locations throughout southern Victoria Land and along the Transantarctic Mountains for six species of endemic microarthropods (Collembola), covering a latitudinal range from 76.0°S to 87.3°S. We assembled individual mitochondrial cyto-chrome c oxidase subunit 1 (COI) sequences (n = 866) and found high levels of sequence divergence at both small (<10 km) and large (>600 km) spatial scales for four of the six Collembola species. We applied molecular clock estimates and assessed genetic divergences relative to the timing of past glacial cycles, including collapses of the West Antarctic Ice Sheet (WAIS). We found that genetically distinct lineages within three species have likely been isolated for at least 5.54 My to 3.52 My, while the other three species diverged more recently (<2 My). We suggest that Collembola had greater dispersal opportunities under past warmer climates, via flotation along coastal margins. Similarly increased opportunities for dispersal may occur under contemporary climate warming scenarios, which could influence the genetic structure of extant populations. As Collembola are a living record of past landscape evolution within Antarctica, these findings provide biological evidence to support geological and glaciological estimates of historical WAIS dynamics over the last ca. 5 My.

%B Proceedings of the National Academy of Sciences %8 08/2020 %G eng %U https://www.pnas.org/content/early/2020/08/19/2007925117 %R 10.1073/pnas.2007925117 %0 Journal Article %J Earth and Planetary Science Letters %D 2020 %T Geochemistry of aeolian material from the McMurdo Dry Valleys, Antarctica: Insights into Southern Hemisphere dust sources %A Melisa A. Diaz %A Welch, Susan A. %A Sheets, J. M. %A Kathleen A. Welch %A Khan, Alia L. %A Byron Adams %A Diane M. McKnight %A Craig S Cary %A W. Berry Lyons %K aeolian material %K Antarctica %K major oxides %K mineralogy %K rare earth elements %K trace elements %X

In the Southern Hemisphere, the major sources of dust and other aeolian materials are from Patagonia, South Africa, Australia, and New Zealand. Dust from Patagonia and New Zealand has been identified in ice cores throughout Antarctica, suggesting that during arid and windy periods, such as glacial periods, dust can be entrained and transported onto the continent. However, little information exists on modern Antarctic dust sources, transport, and its role in the Southern Hemisphere dust cycle. We present the first geochemical characterization of aeolian materials collected at five heights (between 5 cm and 100 cm) above the surface in four valleys within the McMurdo Dry Valleys, the largest ice-free area in Antarctica. Our mineralogy data indicate that these materials are primarily derived from local rocks of the McMurdo Volcanics, Ferrar Dolerite, Beacon Sandstone and Granite Harbor Intrusives, with varying contributions of each rock type dependent on the valley location. While major oxide, trace element and rare earth element data show that low elevation and coastal locations (with respect to the Ross Sea) are dominated by local sources, high elevation and inland locations have accumulated both local materials and dust from other distant Southern Hemisphere sources. This far-traveled material may not be accumulating today, but represents a paleo source that is resuspended from the soils. By geochemically “fingerprinting” aeolian materials from the MDV, we can better inform future studies on the transport of materials within Antarctica and between Southern Hemisphere land masses.

%B Earth and Planetary Science Letters %V 547 %8 10/2020 %G eng %U https://www.sciencedirect.com/science/article/pii/S0012821X20304040 %R 10.1016/j.epsl.2020.116460 %0 Journal Article %J Scientific Data %D 2020 %T A global database of soil nematode abundance and functional group composition %A van den Hoogen, Johan %A Geisen, Stefan %A Diana H. Wall %A Wardle, D %A Traunspurger, Walter %A de Goede, Ron G. M. %A Byron Adams %A Ahmad, Wasim %A Ferris, Howard %A Richard D. Bardgett %A Bonkowski, Michael %A Campos-Herrera, Raquel %A Cares, Juvenil E. %A Caruso, Tancredi %A de Brito Caixeta, Larissa %A Chen, Xiaoyun %A Costa, Sofia R. %A Creamer, Rachel %A da Cunha e Castro, José %A Dam, Marie %A Djigal, Djibril %A Escuer, Miguel %A Griffiths, Bryan S. %A Gutiérrez, Carmen %A Hohberg, Karin %A Kalinkina, Daria %A Kardol, Paul %A Kergunteuil, Alan %A Korthals, Gerard %A Krashevska, Valentyna %A Kudrin, Alexey A. %A Li, Qi %A Liang, Wenju %A Magilton, Matthew %A Marais, Mariette %A Martín, José Antonio Rodríguez %A Matveeva, Elizaveta %A Mayad, El Hassan %A Mzough, E. %A Mulder, Christian %A Mullin, Peter %A Neilson, Roy %A Nguyen, T. A. Duong %A Uffe N. Nielsen %A Okada, Hiroaki %A Rius, Juan Emilio Palomares %A Pan, Kaiwen %A Peneva, Vlada %A Pellissier, Loïc %A Carlos Pereira da Silva, Julio %A Pitteloud, Camille %A Powers, Thomas O. %A Powers, Kirsten %A Quist, Casper W. %A Rasmann, Sergio %A Moreno, Sara Sánchez %A Scheu, Stefan %A Setälä, Heikki %A Sushchuk, Anna %A Tiunov, Alexei V. %A Trap, Jean %A Vestergård, Mette %A Villenave, Cecile %A Waeyenberge, Lieven %A Wilschut, Rutger %A Wright, Daniel G. %A Keith, Aidan M. %A Yang, Jiue-in %A Schmidt, Olaf %A Bouharroud, R. %A Ferji, Z. %A van der Putten, Wim H. %A Routh, Devin %A Crowther, Thomas Ward %X

As the most abundant animals on earth, nematodes are a dominant component of the soil community. they play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.

%B Scientific Data %V 7 %8 03/2020 %G eng %U https://www.nature.com/articles/s41597-020-0437-3 %N 1 %R 10.1038/s41597-020-0437-3 %0 Journal Article %J Environmental Microbiology %D 2020 %T Shotgun metagenomics reveal a diverse assemblage of protists in a model Antarctic soil ecosystem %A Thompson, Andrew R. %A Geisen, Stefan %A Byron Adams %K Antarctica %K extremophiles %K functional groups %K metagenomics %K protozoa %K soil microbiology %X

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.

%B Environmental Microbiology %8 08/2020 %G eng %U https://sfamjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1462-2920.15198 %R 10.1111/1462-2920.15198 %0 Journal Article %J Communications Biology %D 2019 %T Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem %A Charles K. Lee %A Laughlin, Daniel C. %A Bottos, Eric M. %A Caruso, Tancredi %A Joy, Kurt %A John E. Barrett %A Brabyn, Lars %A Uffe N. Nielsen %A Byron Adams %A Diana H. Wall %A D. W. Hopkins %A Pointing, Steve B. %A McDonald, Ian R. %A Cowan, Don A. %A Banks, Jonathan C. %A Stichbury, Glen A. %A Jones, Irfon %A Zawar-Reza, Peyman %A Katurji, Marwan %A Hogg, Ian D. %A Sparrow, Ashley D. %A Storey, Bryan C. %A Allan Green, T. G. %A Craig S Cary %X

Abiotic and biotic factors control ecosystem biodiversity, but their relative contributions remain unclear. The ultraoligotrophic ecosystem of the Antarctic Dry Valleys, a simple yet highly heterogeneous ecosystem, is a natural laboratory well-suited for resolving the abiotic and biotic controls of community structure. We undertook a multidisciplinary investigation to capture ecologically relevant biotic and abiotic attributes of more than 500 sites in the Dry Valleys, encompassing observed landscape heterogeneities across more than 200 km2. Using richness of autotrophic and heterotrophic taxa as a proxy for functional complexity, we linked measured variables in a parsimonious yet comprehensive structural equation model that explained significant variations in biological complexity and identified landscape-scale and fine-scale abiotic factors as the primary drivers of diversity. However, the inclusion of linkages among functional groups was essential for constructing the best-fitting model. Our findings support the notion that biotic interactions make crucial contributions even in an extremely simple ecosystem.

%B Communications Biology %V 2 %8 02/2019 %G eng %U https://www.nature.com/articles/s42003-018-0274-5 %N 1 %! Commun Biol %R 10.1038/s42003-018-0274-5 %0 Journal Article %J Journal of Geophysical Research: Biogeosciences %D 2019 %T The hydroecology of an ephemeral wetland in the McMurdo Dry Valleys, Antarctica %A Wlostowski, Adam %A Schulte, Nicholas O. %A Byron Adams %A Ball, Becky %A Rhea M.M. Esposito %A Michael N. Gooseff %A W. Berry Lyons %A Uffe N. Nielsen %A Ross A. Virginia %A Diana H. Wall %A Kathleen A. Welch %A Diane M. McKnight %K Antarctica %K desert hydrology %K diatom biodiversity %K hyporheic interactions %K wetlands %X

The McMurdo Dry Valleys (MDV) is a polar desert on the coast of East Antarctica where ephemeral wetlands become hydrologically active during warm and sunny summers when sub‐surface flows are generated from melting snowfields. To understand the structure and function of polar wetland ecosystems, we investigated the hydroecology of one such wetland, the Wormherder Creek wetland, during the warm and sunny summer of 2008 – 2009, when the wetland was hydrologically reactivated. Conservative tracer (LiCl) was injected for a 2‐hour period into a stream above the wetland to determine flow path orientations and hydrologic residence times. Tracer results indicated that surface water is rapidly exchanged with wetland groundwater and wetland residence times may exceed two austral summers. Major ion concentrations were uniform in samples from surface water and shallow groundwater throughout the wetland. Microbial mats in the wetland had high autotrophic index values (the ratios of chlorophyll a [Chl‐a]/ash‐free dry mass [AFDM]), ranging from 9‐38 μg Chl‐a/mg AFDM, indicative of actively photosynthesizing mat communities. The diatom communities in the mats were relatively uniform compared to those in mats from regularly flowing MDV streams, with four endemic and one widespread diatom taxa of the genus Luticola accounting for an average of 86% of the community. These results indicate that the hydrologic characteristics of the wetland contribute to uniform geochemical conditions. In turn, uniform geochemical conditions may explain the high autotrophic index values of the microbial mats and relatively low spatial variation of the diatom community.

%B Journal of Geophysical Research: Biogeosciences %8 11/2019 %G eng %U https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JG005153 %R 10.1029/2019JG005153 %0 Journal Article %J Communications Biology %D 2019 %T Nematodes in a polar desert reveal the relative role of biotic interactions in the coexistence of soil animals %A Caruso, Tancredi %A Hogg, Ian D. %A Uffe N. Nielsen %A Bottos, Eric M. %A Charles K. Lee %A D. W. Hopkins %A Craig S Cary %A John E. Barrett %A Green, T. G. Allan %A Storey, Bryan C. %A Diana H. Wall %A Byron Adams %X

Abiotic factors are major determinants of soil animal distributions and their dominant role is pronounced in extreme ecosystems, with biotic interactions seemingly playing a minor role. We modelled co-occurrence and distribution of the three nematode species that dominate the soil food web of the McMurdo Dry Valleys (Antarctica). Abiotic factors, other biotic groups, and autocorrelation all contributed to structuring nematode species distributions. However, after removing their effects, we found that the presence of the most abundant nematode species greatly, and negatively, affected the probability of detecting one of the other two species. We observed similar patterns in relative abundances for two out of three pairs of species. Harsh abiotic conditions alone are insufficient to explain contemporary nematode distributions whereas the role of negative biotic interactions has been largely underestimated in soil. The future challenge is to understand how the effects of global change on biotic interactions will alter species coexistence.

%B Communications Biology %V 2 %8 02/2019 %G eng %U http://www.nature.com/articles/s42003-018-0260-y %N 1 %! Commun Biol %R 10.1038/s42003-018-0260-y %0 Journal Article %J Antarctic Science %D 2019 %T Provisional checklist of terrestrial heterotrophic protists from Antarctica %A Thompson, Andrew R. %A Powell, Gareth S. %A Byron Adams %X

Heterotrophic soil protists encompass lineages that are both evolutionarily ancient and highly diverse, providing an untapped wealth of scientific insight. Yet the diversity of free-living heterotrophic terrestrial protists is still largely unknown. To contribute to our understanding of this diversity, we present a checklist of heterotrophic protists currently reported from terrestrial Antarctica, for which no comprehensive evaluation currently exists. As a polar continent, Antarctica is especially susceptible to rising temperatures caused by anthropogenic climate change. Establishing a baseline for future conservation efforts of Antarctic protists is therefore important. We performed a literature search and found 236 taxa identified to species and an additional 303 taxa identified to higher taxonomic levels in 54 studies spanning over 100 years of research. Isolated by distance, climate and the circumpolar vortex, Antarctica is the most extreme continent on Earth: it is not unreasonable to think that it may host physiologically and evolutionarily unique species of protists, yet currently most species discovered in Antarctica are considered cosmopolitan. Additional sampling of the more extreme intra-continental zones will probably result in the discovery of more novel and unique taxa.

%B Antarctic Science %8 11/2019 %G eng %U https://www.cambridge.org/core/journals/antarctic-science/article/provisional-checklist-of-terrestrial-heterotrophic-protists-from-antarctica/DC08D89ABDC5AF2CC83E38B1C6F1F78C %! Antarctic Science %R 10.1017/S0954102019000361 %0 Journal Article %J Nature %D 2019 %T Soil nematode abundance and functional group composition at a global scale %A van den Hoogen, Johan %A Geisen, Stefan %A Routh, Devin %A Ferris, Howard %A Traunspurger, Walter %A Wardle, D %A de Goede, Ron G. M. %A Byron Adams %A Ahmad, Wasim %A Andriuzzi, Walter S. %A Richard D. Bardgett %A Bonkowski, Michael %A Campos-Herrera, Raquel %A Cares, Juvenil E. %A Caruso, Tancredi %A de Brito Caixeta, Larissa %A Chen, Xiaoyun %A Costa, Sofia R. %A Creamer, Rachel %A Mauro da Cunha Castro, José %A Dam, Marie %A Djigal, Djibril %A Escuer, Miguel %A Griffiths, Bryan S. %A Gutiérrez, Carmen %A Hohberg, Karin %A Kalinkina, Daria %A Kardol, Paul %A Kergunteuil, Alan %A Korthals, Gerard %A Krashevska, Valentyna %A Kudrin, Alexey A. %A Li, Qi %A Liang, Wenju %A Magilton, Matthew %A Marais, Mariette %A Martín, José Antonio Rodríguez %A Matveeva, Elizaveta %A Mayad, El Hassan %A Mulder, Christian %A Mullin, Peter %A Neilson, Roy %A Nguyen, T. A. Duong %A Uffe N. Nielsen %A Okada, Hiroaki %A Rius, Juan Emilio Palomares %A Pan, Kaiwen %A Peneva, Vlada %A Pellissier, Loïc %A Carlos Pereira da Silva, Julio %A Pitteloud, Camille %A Powers, Thomas O. %A Powers, Kirsten %A Quist, Casper W. %A Rasmann, Sergio %A Moreno, Sara Sánchez %A Scheu, Stefan %A Setälä, Heikki %A Sushchuk, Anna %A Tiunov, Alexei V. %A Trap, Jean %A van der Putten, W %A Vestergård, Mette %A Villenave, Cecile %A Waeyenberge, Lieven %A Diana H. Wall %A Wilschut, Rutger %A Wright, Daniel G. %A Yang, Jiue-in %A Crowther, Thomas Ward %X

Soil organisms are a crucial part of the terrestrial biosphere. Despite their importance for ecosystem functioning, few quantitative, spatially explicit models of the active belowground community currently exist. In particular, nematodes are the most abundant animals on Earth, filling all trophic levels in the soil food web. Here we use 6,759 georeferenced samples to generate a mechanistic understanding of the patterns of the global abundance of nematodes in the soil and the composition of their functional groups. The resulting maps show that 4.4 ± 0.64 × 1020 nematodes (with a total biomass of approximately 0.3 gigatonnes) inhabit surface soils across the world, with higher abundances in sub-Arctic regions (38% of total) than in temperate (24%) or tropical (21%) regions. Regional variations in these global trends also provide insights into local patterns of soil fertility and functioning. These high-resolution models provide the first steps towards representing soil ecological processes in global biogeochemical models and will enable the prediction of elemental cycling under current and future climate scenarios.

%B Nature %V 572 %8 08/2019 %G eng %U https://www.nature.com/articles/s41586-019-1418-6 %N 7768 %R 10.1038/s41586-019-1418-6 %0 Journal Article %J Journal of Geophysical Research: Earth Surface %D 2018 %T Aeolian material transport and its role in landscape connectivity in the McMurdo Dry Valleys, Antarctica %A Melisa A. Diaz %A Byron Adams %A Kathleen A. Welch %A Sue Welch %A Opiyo, Stephen O. %A Khan, Alia L. %A Diane M. McKnight %A Craig S Cary %A W. Berry Lyons %X

Arid regions, particularly polar and alpine desert environments, have diminished landscape connectivity compared to temperate regions due to limited and/or seasonal hydrological processes. For these environments, aeolian processes play a particularly important role in landscape evolution and biotic community vitality through nutrient and solute additions. The McMurdo Dry Valleys (MDV) are the largest ice-free area in Antarctica and are potentially a major source of aeolian material for the continent. From this region, samples were collected at five heights (~5, 10, 20, 50, and 100 cm) above the surface seasonally for 2013 through 2015 from Alatna Valley, Victoria Valley, Miers Valley, and Taylor Valley (Taylor Glacier, East Lake Bonney, F6 (Lake Fryxell), and Explorer’s Cove). Despite significant geological separation and varying glacial histories, low-elevation and coastal sites had similar major ion chemistries, as did high-elevation and inland locations. This locational clustering of compositions was also evident in scanning electron microscopy images and principal component analyses, particularly for samples collected at ~100 cm above the surface. Compared to published soil literature, aeolian material in Taylor Valley demonstrates a primarily down-valley transport of material toward the coast. Soluble N:P ratios in the aeolian material reflect relative nutrient enrichments seen in MDV soils and lakes, where younger, coastal soils are relatively N depleted, while older, up-valley soils are relatively P depleted. The aeolian transport of materials, including water-soluble nutrients, is an important vector of connectivity within the MDV and provides a mechanism to help “homogenize” the geochemistry of both soil and aquatic ecosystems.

%B Journal of Geophysical Research: Earth Surface %V 123 %P 3323 - 3337 %8 12/2018 %G eng %U https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017JF004589 %N 12 %! J. Geophys. Res. Earth Surf. %R 10.1029/2017JF004589 %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 Ecology %D 2018 %T Observed trends of soil fauna in the Antarctic Dry Valleys: early signs of shifts predicted under climate change %A Andriuzzi, Walter S. %A Byron Adams %A John E. Barrett %A Ross A. Virginia %A Diana H. Wall %X

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 cool- ing 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 compen- sated for the declining numbers of the dominant species. Interannual variation in the propor- tion 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 spe- cies 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 signif- icant positive relationship with soil moisture. Our findings show that combining an under- standing 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 abun- dance and diversity of soil fauna. 

%B Ecology %V 99 %P 312 - 321 %8 02/2018 %G eng %U http://doi.wiley.com/10.1002/ecy.2090/full %N 2 %! Ecology %R 10.1002/ecy.2090 %0 Journal Article %J Soil Biology and Biochemistry %D 2018 %T Soil biological responses to C, N and P fertilization in a polar desert of Antarctica %A Ball, Becky %A Byron Adams %A John E. Barrett %A Diana H. Wall %A Ross A. Virginia %X

 

In the polar desert ecosystem of the McMurdo Dry Valleys of Antarctica, biology is constrained by available liquid water, low temperatures, as well as the availability of organic matter and nutrient elements. These soil ecosystems are climate-sensitive, where projected future warming may have profound effects on biological communities and biogeochemical cycling. Warmer temperatures will mobilize meltwater from permafrost and glaciers, may increase precipitation and may be accompanied by pulses of nutrient availability. Enhanced water and nutrient availability have the potential to greatly influence desert soil biology and ecosystem processes. The objectives of this 5-year study were to determine which nutrient elements (C, N, P) are most limiting to dry valley soil communities and whether landscape history (i.e., in situ soil type and stoichiometry) influences soil community response to nutrient additions. After 3 years of no noticeable response, soil CO2 flux was significantly higher under addition of C+ N than the other treatments, regardless of in situ soil stoichiometry, but microbial biomass and invertebrate abundance were variable and not influenced in the same manner. A stable isotope incubation suggests that fertilization increases C and N mineralization from organic matter via stimulating microbial activity, with loss of both the applied treatments as well in situ C and N. However, these responses are relatively short-lived, suggesting long-term impacts on C and N cycling would only occur if meltwater and nutrient pulses are sustained over time, a scenario that is increasingly likely for the dry valleys.

 

%B Soil Biology and Biochemistry %V 122 %8 07/2018 %G eng %U http://linkinghub.elsevier.com/retrieve/pii/S0038071718301081 %! Soil Biology and Biochemistry %& 7 %R 10.1016/j.soilbio.2018.03.025 %0 Journal Article %J Journal of Geophysical Research: Biogeosciences %D 2018 %T Soil Moisture Controls the Thermal Habitat of Active Layer Soils in the McMurdo Dry Valleys, Antarctica %A Wlostowski, Adam %A Michael N. Gooseff %A Byron Adams %X

Antarctic soil ecosystems are strongly controlled by abiotic habitat variables. Regional climate change in the McMurdo Dry Valleys is expected to cause warming over the next century, leading to an increase in frequency of freeze-thaw cycling in the soil habitat. Previous studies show that physiological stress associated with freeze-thaw cycling adversely affects invertebrate populations by decreasing abundance and positively selecting for larger body sizes. However, it remains unclear whether or not climate warming will indeed enhance the frequency of annual freeze-thaw cycling and associated physiological stresses. This research quantifies the frequency, rate, and spatial heterogeneity of active layer freezing to better understand how regional climate change may affect active layer soil thermodynamics, and, in turn, affect soil macroinvertebrate communities. Shallow active layer temperature, specific conductance, and soil moisture were observed along natural wetness gradients. Field observations show that the frequency and rate of freeze events are nonlinearly related to freezable soil moisture (θf). Over a 2 year period, soils at θf < 0.080 m3/m3 experienced between 15 and 35 freeze events and froze rapidly compared to soils with θf > 0.080 m3/m3, which experienced between 2 and 6 freeze events and froze more gradually. A numerical soil thermodynamic model is able to simulate observed freezing rates across a range of θf, reinforcing a well-known causal relationship between soil moisture and active layer freezing dynamics. Findings show that slight increases in soil moisture can potentially offset the effect of climate warming on exacerbating soil freeze-thaw cycling.

%B Journal of Geophysical Research: Biogeosciences %V 123 %8 01/2018 %G eng %U https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JG004018 %N 1 %! J. Geophys. Res. Biogeosci. %& 46-59 %R 10.1002/2017JG004018 %0 Journal Article %J Polar Biology %D 2018 %T Spatial and temporal patterns of microbial mats and associated invertebrates along an Antarctic stream %A Andriuzzi, Walter S. %A Lee F. Stanish %A Breana L. Simmons %A Chris Jaros %A Byron Adams %A Diana H. Wall %A Diane M. McKnight %K diatoms %K Disturbance %K Dry valleys %K Epilithon %K Microfauna %K Stream flow %X

 

Microbial biofilms are biological hotspots in many alpine and polar ecosystems, but the controls on and functional significance of their fauna are little known. We studied cyanobacterial mats and the underlying sediment in a glacial meltwater stream in the McMurdo Dry Valleys, Antarctica. We investigated mat biomass (total and phototrophic), diatoms, and micro-meiofauna (nematodes, rotifers, and tardigrades) at nine sites along a 1670 m stream reach in a cold, low-flow growing season, and in a warmer growing season in which peak flows (above 100 L s−1) scoured the mats. Diatom and invertebrate communities were not related, but mat biomass in the low-flow year was negatively related to nematode abundance, including that of the omnivore Eudorylaimus. In the high-flow year that followed, invertebrate abundance was reduced in the mats, diatom community structure was altered, and mat biomass was higher. The difference in invertebrate abundance between years was greater in mats in upstream reaches, where the greatest increases in flow velocity may have occurred, and was negligible in mats in downstream reaches as well as in the sediment beneath the mats. Integrating our results with previous findings, we generate two predictive hypotheses to be tested in glacial meltwater streams: (1) under peak flows invertebrates decline in the microbial mats, while (2) the sediment beneath the mats is a refuge from the flow disturbance. Our results also suggest that, under stable flow conditions, microinvertebrate grazers could exert top-down control on microbial mat biomass.

 

%B Polar Biology %V 41 %P 1911–1921 %8 10/2018 %G eng %U http://link.springer.com/10.1007/s00300-018-2331-4 %N 10 %! Polar Biol %R 10.1007/s00300-018-2331-4 %0 Journal Article %J Polar Biology %D 2018 %T Stable C and N isotope ratios reveal soil food web structure and identify the nematode Eudorylaimus antarcticus as an omnivore–predator in Taylor Valley, Antarctica %A Shaw, E. Ashley %A Byron Adams %A John E. Barrett %A W. Berry Lyons %A Ross A. Virginia %A Diana H. Wall %X

Soil food webs of the McMurdo Dry Valleys, Antarctica are simple. These include primary trophic levels of mosses, algae, cyanobacteria, bacteria, archaea, and fungi, and their protozoan and metazoan consumers (including relatively few species of nematodes, tardigrades, rotifers, and microarthropods). These biota are patchily distributed across the landscape, with greatest faunal biodiversity associated with wet soil. Understanding trophic structure is critical to studies of biotic interactions and distribution; yet, McMurdo Dry Valley soil food web structure has been inferred from limited laboratory culturing and micro- scopic observations. To address this, we measured stable isotope natural abundance ratios of C (13C/12C) and N (15N/14N) for di erent metazoan taxa (using whole body biomass) to determine soil food web structure in Taylor Valley, Antarctica. Nitrogen isotopes were most useful in di erentiating trophic levels because they fractionated predictably at higher trophic levels. Using 15N/14N, we found that three trophic levels were present in wet soil habitats. While cyanobacterial mats were the primary trophic level, the nematode Plectus murrayi, tardigrade Acutuncus antarcticus, and rotifers composed a secondary trophic level of grazers. Eudorylaimus antarcticus had a 15N/14N ratio that was 2–4‰ higher than that of grazers, indicating that this species is the sole member of a tertiary trophic level. Understanding the trophic positions of soil fauna is critical to predictions of current and future species interactions and their distributions for the McMurdo Dry Valleys, Antarctica.

%B Polar Biology %V 41 %P 1013–1018 %8 05/2018 %G eng %U http://link.springer.com/10.1007/s00300-017-2243-8 %N 5 %! Polar Biol %R 10.1007/s00300-017-2243-8 %0 Journal Article %J Frontiers in Microbiology %D 2018 %T Stoichiometric Shifts in Soil C:N:P Promote Bacterial Taxa Dominance, Maintain Biodiversity, and Deconstruct Community Assemblages %A Aanderud, Zachary T. %A Saurey, Sabrina D. %A Ball, Becky %A Diana H. Wall %A John E. Barrett %A Muscarella, Mario E. %A Griffin, Natasha A. %A Ross A. Virginia %A Byron Adams %K ecological stoichiometry %K Lake Fryxell Basin %K McMurdo Dry Valleys %K network community modeling %K nutrient colimitation %K Solirubrobacteriaceae %X

Imbalances in C:N:P supply ratios may cause bacterial resource limitations and constrain biogeochemical processes, but the importance of shifts in soil stoichiometry are complicated by the nearly limitless interactions between an immensely rich species pool and a multiple chemical resource forms. To more clearly identify the impact of soil C:N:P on bacteria, we evaluated the cumulative effects of single and coupled long-term nutrient additions (i.e., C as mannitol, N as equal concentrations NH4 + and NO3 − , and P as Na3PO4) and water on communities in an Antarctic polar desert, Taylor Valley. Untreated soils possessed relatively low bacterial diversity, simplified organic C sources due to the absence of plants, limited inorganic N, and excess soil P potentially attenuating links between C:N:P. After 6 years of adding resources, an alleviation of C and N colimitation allowed one rare Micrococcaceae, an Arthrobacter species, to dominate, comprising 47% of the total community abundance and elevating soil respiration by 136% relative to untreated soils. The addition of N alone reduced C:N ratios, elevated bacterial richness and diversity, and allowed rare taxa relying on ammonium and nitrite for metabolism to become more abundant [e.g., nitrite oxidizing Nitrospira species (Nitrosomonadaceae), denitrifiers utilizing nitrite (Gemmatimonadaceae) and members of Rhodobacteraceae with a high affinity for ammonium]. Based on community co-occurrence networks, lower C:P ratios in soils following P and CP additions created more diffuse and less connected communities by disrupting 73% of species interactions and selecting for taxa potentially exploiting abundant P. Unlike amended nutrients, water additions alone elicited no lasting impact on communities. Our results suggest that as soils become nutrient rich a wide array of outcomes are possible from species dominance and the deconstruction of species interconnectedness to the maintenance of biodiversity.

%B Frontiers in Microbiology %V 9 %8 07/2018 %G eng %U https://www.frontiersin.org/article/10.3389/fmicb.2018.01401/full %! Front. Microbiol. %R 10.3389/fmicb.2018.01401 %0 Journal Article %J Nature Ecology & Evolution %D 2017 %T Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica %A Michael N. Gooseff %A John E. Barrett %A Byron Adams %A Peter T. Doran %A Andrew G Fountain %A W. Berry Lyons %A Diane M. McKnight %A John C. Priscu %A Eric R. Sokol %A Cristina D. Takacs-Vesbach %A Martijn L. Vandegehuchte %A Ross A. Virginia %A Diana H. Wall %B Nature Ecology & Evolution %V 1 %P 1334-1338 %8 09/2017 %G eng %U https://www.nature.com/articles/s41559-017-0253-0 %N 9 %! Nat Ecol Evol %R 10.1038/s41559-017-0253-0 %0 Journal Article %J Ecology Letters %D 2017 %T Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze-thaw cycles, in the Antarctic Dry Valleys %A Matthew Knox %A Andriuzzi, Walter S. %A Heather N. Buelow %A Cristina D. Takacs-Vesbach %A Byron Adams %A Diana H. Wall %X

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.

%B Ecology Letters %V 20 %P 1242-1249 %8 10/2017 %G eng %U http://onlinelibrary.wiley.com/doi/10.1111/ele.12819/full %N 10 %! Ecol Lett %R 10.1111/ele.12819 %0 Journal Article %J Frontiers in Microbiology %D 2016 %T Aerobiology Over Antarctica – A New Initiative for Atmospheric Ecology %A Pearce, David A. %A Alekhina, Irina A. %A Terauds, Aleks %A Wilmotte, Annick %A Quesada, Antonio %A Edwards, Arwyn %A Dommergue, Aurelien %A Sattler, Birgit %A Byron Adams %A Magalhaes, Catarina %A Chu, Wan-Loy %A Lau, Maggie C. Y. %A Craig S Cary %A Smith, David J. %A Diana H. Wall %A Eguren, Gabriela %A Matcher, Gwynneth %A Bradley, James A. %A de Vera, Jean-Pierre %A Elster, Josef %A Hughes, Kevin A. %A Cuthbertson, Lewis %A Benning, Liane G. %A Gunde-Cimerman, Nina %A Convey, Peter %A Hong, Soon Gyu %A Pointing, Steve B. %A Pellizari, Vivian H. %A Vincent, Warwick F. %B Frontiers in Microbiology %V 776796194610314927235011365134445142846479110123936574 %8 02/2016 %G eng %U http://journal.frontiersin.org/Article/10.3389/fmicb.2016.00016/abstract %N 53307413 %! Front. Microbiol. %R 10.3389/fmicb.2016.00016 %0 Journal Article %J Genome %D 2016 %T Genetic diversity among populations of Antarctic springtails (Collembola) within the Mackay Glacier ecotone 1 %A Clare R. Beet %A Hogg, Ian D. %A Gemma E. Collins %A Cowan, Don A. %A Diana H. Wall %A Byron Adams %A John-James Wilson %B Genome %V 59 %P 762 - 770 %8 Jan-09-2016 %G eng %U http://www.nrcresearchpress.com/doi/10.1139/gen-2015-0194 %N 9 %! Genome %R 10.1139/gen-2015-0194 %0 Journal Article %J Biological Journal of the Linnean Society %D 2016 %T High levels of intraspecific genetic divergences revealed for Antarctic springtails: evidence for small-scale isolation during Pleistocene glaciation %A Bennett, Kristi R. %A Hogg, Ian D. %A Byron Adams %A Hebert, Paul D. N. %B Biological Journal of the Linnean Society %V 119 %P 166 - 178 %8 Jan-09-2016 %G eng %U https://academic.oup.com/biolinnean/article-lookup/doi/10.1111/bij.12796https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fbij.12796 %N 1 %! Biol. J. Linn. Soc. %R 10.1111/bij.12796 %0 Journal Article %J BioScience %D 2016 %T The Impact of a Large-Scale Climate Event on Antarctic Ecosystem Processes %A Andrew G Fountain %A Saba, Grace %A Byron Adams %A Peter T. Doran %A Fraser, William %A Michael N. Gooseff %A Maciek K. Obryk %A John C. Priscu %A Sharon E. Stammerjohn %A Ross A. Virginia %X

Extreme climate and weather events, such as a drought, hurricanes, or ice storms, can strongly imprint ecosystem processing and may alter ecosystem structure. Ecosystems in extreme environments are particularly vulnerable because of their adaptation to severe limitations in energy, water, or nutrients. The vulnerability can be expressed as a relatively long-lasting ecosystem response to a small or brief change in environmental conditions. Such an event occurred in Antarctica and affected two vastly different ecosystems: a marine-dominated coastal system and a terrestrial polar desert. Both sites experienced winds that warmed air temperatures above the 0°C threshold, resulting in extensive snow and ice melt and triggering a series of cascading effects through the ecosystems that are continuing to play out more than a decade later. This highlights the sensitivity of Antarctic ecosystems to warming events, which should occur more frequently in the future with global climate warming.

%B BioScience %V 66 %P 848 - 863 %8 10/2016 %G eng %U http://academic.oup.com/bioscience/article-pdf/66/10/848/7510601/biw110.pdf %N 10 %R 10.1093/biosci/biw110 %0 Journal Article %J Polar Biology %D 2016 %T Impact of diurnal freeze–thaw cycles on the soil nematode Scottnema lindsayae in Taylor Valley, Antarctica %A Matthew Knox %A Diana H. Wall %A Ross A. Virginia %A Martijn L. Vandegehuchte %A Inigo San Gil %A Byron Adams %B Polar Biology %V 39 %P 583 - 592 %8 04/2016 %G eng %U https://link.springer.com/article/10.1007/s00300-015-1809-6 %N 4 %! Polar Biol %R 10.1007/s00300-015-1809-6 %0 Journal Article %J Invertebrate Systematics %D 2015 %T Mitochondrial DNA analyses reveal widespread tardigrade diversity in Antarctica %A Velasco-Castrillon, Alejandro %A McInnes, Sandra J. %A Schultz, Mark B. %A Arroniz-Crespo, Maria %A D'Haese, Cyrille A. %A Gibson, John A. E. %A Byron Adams %A Page, Timothy J. %A Austin, Andrew D. %A Cooper, Steven J. B. %A Stevens, Mark I. %B Invertebrate Systematics %V 29 %P 578 %8 12/2015 %G eng %U http://www.publish.csiro.au/?paper=IS14019 %N 6 %! Invert. Systematics %R 10.1071/IS14019 %0 Journal Article %J ZooKeys %D 2014 %T Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica %A Byron Adams %A Diana H. Wall %A Ross A. Virginia %A Broos, Emma %A Matthew Knox %B ZooKeys %V 419 %P 29 - 71 %8 06/2015 %G eng %U http://zookeys.pensoft.net/articles.php?id=3899 %! ZK %R 10.3897/zookeys.419.7180 %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 Journal of nematology %D 2013 %T The Life Cycle of the Antarctic Nematode Plectus murrayi Under Laboratory Conditions. %A Cecilia M. Tomasel %A Byron Adams %A Fernando G. Tomasel %A Diana H. Wall %B Journal of nematology %V 45 %P 39-42 %8 2013 Mar %G eng %U http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3625130/ %N 1 %0 Journal Article %J Eos, Transactions American Geophysical Union %D 2013 %T Understanding Terrestrial Ecosystem Response to Antarctic Climate Change %A Joseph S. Levy %A W. Berry Lyons %A Byron Adams %B Eos, Transactions American Geophysical Union %V 94 %P 33 - 33 %8 01/2013 %G eng %U http://onlinelibrary.wiley.com/doi/10.1002/2013EO030009/abstract %N 3 %R 10.1002/2013EO030009 %0 Journal Article %J Invertebrate Systematics %D 2012 %T Antarctic Tardigrada: a first step in understanding molecular operational taxonomic units (MOTUs) and biogeography of cryptic meiofauna %A Czechowski, Paul %A Sands, Chester J. %A Byron Adams %A D'Haese, Cyrille A. %A John A. E. Gibson %A McInnes, Sandra J. %A Stevens, Mark I. %B Invertebrate Systematics %V 26 %P 526 %8 12/2012 %G eng %N 6 %R 10.1071/IS12034 %0 Journal Article %J Proceedings Bational Academy of Sciences %D 2012 %T Cross-biome metagenomic analyses of soil microbial communities and their functional attributes %A Noah Fierer %A Jonathan W. Leff %A Byron Adams %A Uffe N. Nielsen %A Scott T. Bates %A Christian L. Lauber %A Sarah Owens %A Jack A. Gilbert %A Diana H. Wall %A J. Gregory Caporaso %B Proceedings Bational Academy of Sciences %8 11/2012 %G eng %U www.pnas.org/cgi/doi/10.1073/pnas.1215210110 %R 10.1073/pnas.1215210110 %0 Journal Article %J Ecosphere %D 2012 %T The ecology of pulse events: insights from an extreme climatic event in a polar desert ecosystem %A Uffe N. Nielsen %A Diana H. Wall %A Byron Adams %A Ross A. Virginia %A Ball, Becky %A Michael N. Gooseff %A Diane M. McKnight %B Ecosphere %V 3 %P art17 %8 02/2012 %G eng %U http://www.esajournals.org/doi/abs/10.1890/ES11-00325.1 %N 2 %R 10.1890/ES11-00325.1 %0 Journal Article %J Pedobiologia %D 2012 %T Thawing permafrost alters nematode populations and soil habitat characteristics in an Antarctic polar desert ecosystem %A Smith, T.E. %A Diana H. Wall %A Hogg, I %A Byron Adams %A Uffe N. Nielsen %A Ross A. Virginia %B Pedobiologia %V 55 %P 75 - 81 %8 3/2012 %G eng %U http://www.sciencedirect.com/science/article/pii/S0031405611001156 %N 2 %R 10.1016/j.pedobi.2011.11.001 %0 Journal Article %J Polar Biology %D 2011 %T Antarctic nematode communities: observed and predicted responses to climate change %A Uffe N. Nielsen %A Diana H. Wall %A Byron Adams %A Ross A. Virginia %B Polar Biology %V 34 %P 1701 - 1711 %8 11/2011 %G eng %U http://www.springerlink.com/content/v588t5671p1w1323/ %N 11 %R 10.1007/s00300-011-1021-2 %0 Book Section %B Molecular and Physiological Basis of Nematode Survival %D 2011 %T Molecular analysis of desiccation survival in Antarctic nematodes %A Bishwo N. Adhikari %A Byron Adams %B Molecular and Physiological Basis of Nematode Survival %I CABI International %C Wallingford %P 205-232 %@ 9781845936877 %G eng %0 Book %D 2011 %T Molecular and physiological basis of nematode survival: Molecular analyses of desiccation survival in Antarctic nematodes. %A Bishwo N. Adhikari %A Byron Adams %E Perry, R. N. %E Wharton, D. A. %I CABI %C Wallingford %P 205 - 232 %G eng %R 10.1079/9781845936877.0205 %0 Journal Article %J Antarctic Science %D 2011 %T Nematode communities of Byers Peninsula, Livingston Island, maritime Antarctica %A Uffe N. Nielsen %A Diana H. Wall %A Li, Grace %A Toro, Manuel %A Byron Adams %A Ross A. Virginia %B Antarctic Science %V 23 %P 349 - 357 %8 8/2011 %G eng %N 04 %R 10.1017/S0954102011000174 %0 Journal Article %J Cold Spring Harbor Protocols %D 2010 %T The Antarctic Nematode Plectus murrayi: An Emerging Model to Study Multiple Stress Survival %A Bishwo N. Adhikari %A Cecilia M. Tomasel %A Li, G %A Diana H. Wall %A Byron Adams %B Cold Spring Harbor Protocols %V 2010 %P pdb.emo142 - pdb.emo142 %8 11/2010 %G eng %N 11 %R 10.1101/pdb.emo142 %0 Journal Article %J Cold Spring Harbor Protocols %D 2010 %T Culturing the Antarctic Nematode Plectus murrayi %A Bishwo N. Adhikari %A Cecilia M. Tomasel %A Li, G %A Diana H. Wall %A Byron Adams %B Cold Spring Harbor Protocols %V 2010 %P pdb.prot5522 - pdb.prot5522 %8 11/2010 %G eng %U http://cshprotocols.cshlp.org/content/2010/11/pdb.emo142.short %N 11 %R 10.1101/pdb.prot5522 %0 Journal Article %J Journal of Experimental Biology %D 2010 %T Effect of slow desiccation and freezing on gene transcription and stress survival of an Antarctic nematode %A Bishwo N. Adhikari %A Diana H. Wall %A Byron Adams %B Journal of Experimental Biology %V 213 %P 1803 - 1812 %8 06/2010 %G eng %N 11 %R 10.1242/jeb.032268 %0 Journal Article %J Polar Biology %D 2010 %T Experimentally increased snow accumulation alters soil moisture and animal community structure in a polar desert %A Edward Ayres %A Johnson N. Nkem %A Diana H. Wall %A Byron Adams %A John E. Barrett %A Breana L. Simmons %A Ross A. Virginia %A Andrew G Fountain %B Polar Biology %V 33 %P 897 - 907 %8 7/2010 %G eng %N 7 %R 10.1007/s00300-010-0766-3 %0 Thesis %B Department of Biology %D 2010 %T Genomic analysis of nematode-environment interaction %A Bishwo N. Adhikari %A Byron Adams %K anhydrobiosis %K Antarctic nematode %K comparative transcriptomics %K complementary DNA library %K desiccation %K functional analysis %K Heterorhabditis bacteriophora %K McMurdo Dry Valleys %K microarray analysis %K Plectus murrayi %K quantative real-time polymerase chain reaction %K Scottnema lindsayae %K stoichiometry %K stress survival %K subtractive hybridization %K trait deterioration %K transcriptional profiling %X

The natural environments of organisms present a multitude of biotic and abiotic challenges that require both short-term ecological and long-term evolutionary responses. Though most environmental response studies have focused on effects at the ecosystem, community and organismal levels, the ultimate controls of these responses are located in the genome of the organism. Soil nematodes are highly responsive to, and display a wide variety of responses to changing environmental conditions, making them ideal models for the study of organismal interactions with their environment. In an attempt to examine responses to environmental stress (desiccation and freezing), genomic level analyses of gene expression during anhydrobiosis of the Antarctic nematode Plectus murrayi was undertaken. An EST library representative of the desiccation induced transcripts was established and the transcripts differentially expressed during desiccation stress were identified. The expressed genome of P. murrayi showed that desiccation survival in nematodes involves differential expression of a suite of genes from diverse functional areas, and constitutive expression of a number of stress related genes. My study also revealed that exposure to slow desiccation and freezing plays an important role in the transcription of stress related genes, improves desiccation and freezing survival of nematodes. Deterioration of traits essential for biological control has been recognized in diverse biological control agents including insect pathogenic nematodes. I studied the genetic mechanisms behind such deterioration using expression profiling. My results showed that trait deterioration of insect pathogenic nematode induces substantial overall changes in the nematode transcriptome and exhibits a general pattern of metabolic shift causing massive changes in metabolic and other processes. Finally, through field observations and molecular laboratory experiments the validity of the growth rate hypothesis in natural populations of Antarctic nematodes was tested. My results indicated that elemental stoichiometry influences evolutionary adaptations in gene expression and genome evolution. My study, in addition to providing immediate insight into the mechanisms by which multicellular animals respond to their environment, is transformative in its potential to inform other fundamental ecological and evolutionary questions, such as the evolution of life-history patterns and the relationship between community structure and ecological function in ecosystems.

%B Department of Biology %I Brigham Young University %C Provo, UT %V Ph.D. %8 08/2010 %G eng %U https://scholarsarchive.byu.edu/etd/2578 %9 doctoral %0 Journal Article %J Antarctic Science %D 2010 %T Latitudinal distribution and mitochondrial DNA (COI) variability of Stereotydeus spp. (Acari: Prostigmata) in Victoria Land and the central Transantarctic Mountains %A Demetras, Nicholas J. %A Hogg, I %A Banks, Jonathan C. %A Byron Adams %B Antarctic Science %V 22 %P 749 - 756 %8 12/2010 %G eng %N 06 %R 10.1017/S0954102010000659 %0 Journal Article %J BMC GENOMICS %D 2009 %T Desiccation survival in an Antarctic nematode: molecular analysis using expressed sequenced tags. %A Bishwo N. Adhikari %A Diana H. Wall %A Byron Adams %B BMC GENOMICS %V 10 %P 69 %8 09/2009 %G eng %U http://www.biomedcentral.com/1471-2164/10/69 %R 10.1186/1471-2164-10-69 %0 Journal Article %J BMC Ecology %D 2009 %T Environmental DNA sequencing primers for eutardigrades and bdelloid rotifers %A Robeson, Michael S %A Costello, Elizabeth K %A Freeman, Kristen R %A Whiting, Jeremy %A Byron Adams %A Martin, Andrew P %A Schmidt, Steve K %B BMC Ecology %V 9 %P 25 %8 11/2009 %G eng %N 1 %R 10.1186/1472-6785-9-25 %0 Journal Article %J Soil Biology & Biochemistry %D 2009 %T Long-term experimental warming reduces soil nematode populations in the McMurdo Dry Valleys, Antarctica %A Breana L. Simmons %A Diana H. Wall %A Byron Adams %A Edward Ayres %A John E. Barrett %A Ross A. Virginia %B Soil Biology & Biochemistry %V 41 %P 2052-2060 %G eng %R 10.1016/j.soilbio.2009.07.009 %0 Journal Article %J Polar Biology %D 2009 %T Terrestrial mesofauna in above- and below-ground habitats: Taylor Valley, Antarctica %A Breana L. Simmons %A Diana H. Wall %A Byron Adams %A Edward Ayres %A John E. Barrett %A Ross A. Virginia %B Polar Biology %V 32 %P 1549-1558 %G eng %R LTER %0 Journal Article %J Oikos %D 2009 %T Where's the ecology in molecular ecology? %A Jerry B. Johnson %A Scott M. Peat %A Byron Adams %B Oikos %V 118 %P 1601-1609 %8 05/2009 %G eng %R 10.1111/j.1600-0706.2009.17557.x %0 Journal Article %J Global Change Biology %D 2008 %T Decline in a dominant invertebrate species contributes to altered carbon cycling in a low-diversity soil ecosystem %A John E. Barrett %A Ross A. Virginia %A Diana H. Wall %A Byron Adams %B Global Change Biology %V 14 %P 1734-1744 %G eng %R LTER %0 Journal Article %J Conservation Biology %D 2008 %T Effects of Human Trampling on Populations of Soil Fauna in the McMurdo Dry Valleys, Antarctica. %A Edward Ayres %A Johnson N. Nkem %A Diana H. Wall %A Byron Adams %A John E. Barrett %A Broos, E %A Andrew N. Parsons %A Powers, Laura E. %A Breana L. Simmons %A Ross A. Virginia %X

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 CO2 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.

%B Conservation Biology %V 22 %P 1544-1551 %8 12/2008 %G eng %N 6 %R 10.1111/j.1523-1739.2008.01034.x %0 Journal Article %J Polar Biology %D 2007 %T The southernmost worm, Scottnema lindsayae (Nematoda): diversity, dispersal and ecological stability. %A Byron Adams %A Diana H. Wall %A Gozel, U %A Dillman, A %A Chaston, J %A Hogg, I %B Polar Biology %V 30 %P 809-815 %G eng %R LTER %0 Journal Article %J Ecosystems %D 2007 %T Unique similarity of faunal communities across aquatic terrestrial interfaces in a polar desert ecosystem %A Edward Ayres %A Diana H. Wall %A Byron Adams %A John E. Barrett %A Ross A. Virginia %B Ecosystems %G eng %R LTER %0 Journal Article %J Soil Biology and Biochemistry %D 2006 %T Biotic interactions in Antarctic terrestrial ecosystems: Are they a factor? %A Hogg, I %A Diana H. Wall %A Craig S Cary %A Convey, K %A Newsham, K %A ODonnell, G %A Byron Adams %A Aislabie, J %A Francesco Frati %A Stevens, M %B Soil Biology and Biochemistry %V 38 %P 3035-3040 %G eng %U http://www.sciencedirect.com/science/article/pii/S0038071706002173 %N 10 %R 10.1016/j.soilbio.2006.04.026 %0 Journal Article %J Antarctic Science %D 2006 %T Co-variation in soil biodiversity and biogeochemistry in Northern and Southern Victoria Land, Antarctica %A John E. Barrett %A Ross A. Virginia %A Diana H. Wall %A Craig S Cary %A Byron Adams %A Hacker, A %A Aislabie, J %B Antarctic Science %V 18 %P 535-548 %G eng %U https://www.cambridge.org/core/journals/antarctic-science/article/covariation-in-soil-biodiversity-and-biogeochemistry-in-northern-and-southern-victoria-land-antarctica/C3514C28DB75F3A19DB5F266D4B1B56E %R 10.1017/S0954102006000587 %0 Journal Article %J Soil Biology and Biochemistry %D 2006 %T Diversity and distribution of Victoria Land biota %A Byron Adams %A Connell, L %A Peter Convey %A Fell, J %A Francesco Frati %A Hogg, I %A Newsham, K %A O'Donnell, A %A Russell, N %A Seppelt, R %A Stevens, M %A Richard D. Bardgett %A Edward Ayres %A Diana H. Wall %A Aislabie, J %A Bamforth, S %A Bargagli, R %A Craig S Cary %A Cavacini, P %B Soil Biology and Biochemistry %V 38 %P 3003-3018 %G eng %U https://www.sciencedirect.com/science/article/abs/pii/S0038071706002215 %R 10.1016/j.soilbio.2006.04.030 %0 Journal Article %J Soil Biology and Biochemistry %D 2006 %T A synthesis of soil biodiversity and ecosystem functioning in Victoria Land, Antarctica %A Diana H. Wall %A Byron Adams %A John E. Barrett %A D. W. Hopkins %B Soil Biology and Biochemistry %V 38 %P 3001-3002 %G eng %R LTER %0 Journal Article %J Polar Biology %D 2006 %T Wind dispersal of soil invertebrates in the McMurdo Dry Valleys, Antarctica %A Johnson N. Nkem %A Diana H. Wall %A Ross A. Virginia %A John E. Barrett %A Broos, E %A Porazinska, D %A Byron Adams %K Biggie %X

Dispersal of soil organisms is crucial for their spatial distribution and adaptation to the prevailing conditions of the Antarctic Dry Valleys. This study investigated the possibility of wind dispersal of soil invertebrates within the dry valleys. Soil invertebrates were evaluated in (1) pockets of transported sediments to lake ice and glacier surfaces, (2) wind-transported dust particles in collection pans (Bundt pans) 100 cm above the soil surface, and (3) sediments transported closer to the surface (<50 cm) and collected in open top chambers (OTCs). Invertebrates were extracted and identified. Nematodes were identified to species and classified according to life stage and sex. Three species of nematodes were recovered and Scottnema lindsayae was the most dominant. There were more juveniles (∼71%) in the transported sediments than adults (29%). Tardigrades and rotifers were more abundant in sediments on lake and glacier surfaces while nematodes were more abundant in the dry sediment collections of Bundt pans and OTCs. The abundance of immobile (dead) nematodes in the Bundt pans and OTCs was three times greater than active (live) nematodes. Anhydrobiosis constitutes a survival mechanism that allows wind dispersal of nematodes in the McMurdo Dry Valleys. Our results show that soil invertebrates are dispersed by wind in the Dry Valleys and are viable in ice communities on lake surfaces and glaciers.

%B Polar Biology %V 29 %P 346-352 %G eng %U http://link.springer.com/content/pdf/10.1007%2Fs00300-005-0061-x %R 10.1007/s00300-005-0061-x