@article {4842, title = {Biogeography and genetic diversity of terrestrial mites in the Ross Sea region, Antarctica}, journal = {Genes}, volume = {14}, year = {2023}, month = {03/2023}, pages = {606}, abstract = {

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.

}, keywords = {LTER-MCM, Acari, Antarctic conservation, DNA barcoding, geographic isolation, speciation}, doi = {10.3390/genes14030606}, url = {https://www.mdpi.com/2073-4425/14/3/606}, author = {Gemma E. Collins and Young, Monica R. and Peter Convey and Steven L. Chown and Craig S Cary and Byron Adams and Diana H. Wall and Hogg, Ian D.} } @article {4153, title = {Biotic interactions are an unexpected yet critical control on the complexity of an abiotically driven polar ecosystem}, journal = {Communications Biology}, volume = {2}, year = {2019}, month = {02/2019}, abstract = {

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.

}, keywords = {LTER-MCM}, doi = {10.1038/s42003-018-0274-5}, url = {https://www.nature.com/articles/s42003-018-0274-5}, author = {Charles K. Lee and Laughlin, Daniel C. and Bottos, Eric M. and Caruso, Tancredi and Joy, Kurt and John E. Barrett and Brabyn, Lars and Uffe N. Nielsen and Byron Adams and Diana H. Wall and D. W. Hopkins and Pointing, Steve B. and McDonald, Ian R. and Cowan, Don A. and Banks, Jonathan C. and Stichbury, Glen A. and Jones, Irfon and Zawar-Reza, Peyman and Katurji, Marwan and Hogg, Ian D. and Sparrow, Ashley D. and Storey, Bryan C. and Allan Green, T. G. and Craig S Cary} } @article {4334, title = {Biotic interactions in experimental Antarctic soil microcosms vary with abiotic stress}, journal = {Soil Systems}, volume = {3}, year = {2019}, month = {08/2019}, abstract = {

Biotic interactions structure ecological communities but abiotic factors affect the strength of these relationships. These interactions are difficult to study in soils due to their vast biodiversity and the many environmental factors that affect soil species. The McMurdo Dry Valleys (MDV), Antarctica, are relatively simple soil ecosystems compared to temperate soils, making them an excellent study system for the trophic relationships of soil. Soil microbes and relatively few species of nematodes, rotifers, tardigrades, springtails, and mites are patchily distributed across the cold, dry landscape, which lacks vascular plants and terrestrial vertebrates. However, glacier and permafrost melt are expected to cause shifts in soil moisture and solutes across this ecosystem. To test how increased moisture and salinity affect soil invertebrates and their biotic interactions, we established a laboratory microcosm experiment (4 community \× 2 moisture \× 2 salinity treatments). Community treatments were: (1) Bacteria only (control), (2) Scottnema (S. lindsayae + bacteria), (3) Eudorylaimus (E. antarcticus + bacteria), and (4) Mixed (S. lindsayae + E. antarcticus + bacteria). Salinity and moisture treatments were control and high. High moisture reduced S. lindsayae adults, while high salinity reduced the total S. lindsayae population. We found that S. lindsayae exerted top-down control over soil bacteria populations, but this effect was dependent on salinity treatment. In the high salinity treatment, bacteria were released from top-down pressure as S. lindsayae declined. Ours was the first study to empirically demonstrate, although in lab microcosm conditions, top-down control in the MDV soil food web.

}, keywords = {LTER-MCM, bacteria, biological interactions, desert, nematode, polar, soil communities, top-down effects, trophic interactions}, doi = {10.3390/soilsystems3030057}, url = {https://www.mdpi.com/2571-8789/3/3/57}, author = {Shaw, E. Ashley and Diana H. Wall} } @article {1236, title = {Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems}, journal = {Journal of Geophysical Research}, volume = {112}, year = {2007}, month = {02/2007}, pages = {G01010+12}, abstract = {

Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10\–106\ years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.

}, keywords = {LTER-MCM, Biggie}, doi = {10.1029/2005JG000141}, author = {John E. Barrett and Ross A. Virginia and W. Berry Lyons and Diane M. McKnight and John C. Priscu and Andrew G Fountain and Diana H. Wall and Daryl L. Moorhead and Peter T. Doran} } @article {1263, title = {Biotic interactions in Antarctic terrestrial ecosystems: Are they a factor?}, journal = {Soil Biology and Biochemistry}, volume = {38}, year = {2006}, pages = {3035-3040}, keywords = {LTER-MCM}, doi = {10.1016/j.soilbio.2006.04.026}, url = {http://www.sciencedirect.com/science/article/pii/S0038071706002173}, author = {Hogg, I and Diana H. Wall and Craig S Cary and Convey, K and Newsham, K and ODonnell, G and Byron Adams and Aislabie, J and Francesco Frati and Stevens, M} } @article {1287, title = {Biodiversity and ecosystem functioning in terrestrial habitats of Antarctica}, journal = {Antarctic Science}, volume = {17}, year = {2005}, month = {07/2005}, pages = {523-531}, keywords = {LTER-MCM}, doi = {10.1017/S0954102005002944}, url = {http://journals.cambridge.org/download.php?file=\%2FANS\%2FANS17_04\%2FS0954102005002944a.pdf\&code=f0bfb3b7eb4345bde6bbfbf916a408e1}, author = {Diana H. Wall} } @article {1323, title = {The Biodiversity and Biogeochemistry of Cryoconite Holes from McMurdo Dry Valley Glaciers, Antarctica}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {36}, year = {2004}, pages = {84-91}, keywords = {LTER-MCM}, author = {Porazinska, D and Andrew G Fountain and Thomas H. Nylen and Martyn Tranter and Ross A. Virginia and Diana H. Wall} } @inbook {1411, title = {Basic Principles in ecosystem functioning}, booktitle = {Encyclopedia of Biodiversity}, volume = {2}, year = {2001}, pages = {345-352}, publisher = {Academic Press}, organization = {Academic Press}, keywords = {LTER-MCM}, author = {Ross A. Virginia and Diana H. Wall}, editor = {S. Levin} } @article {1399, title = {Biodiversity in critical transition zones between terrestrial freshwater and marine soils and sediments: processes, linkages, and management implications.}, journal = {Ecosystems}, volume = {4}, year = {2001}, pages = {418-420}, keywords = {LTER-MCM}, author = {Diana H. Wall and M.A. Palmer and P.V.R. Snelgrove} } @article {1425, title = {Biodiversity above and below the surface of soils and sediments: linkages and implications for global change}, journal = {Bioscience}, volume = {50}, year = {2000}, pages = {1043-1048}, keywords = {LTER-MCM}, doi = {10.1641/0006-3568(2000)050[1043:BAABTS]2.0.CO;2}, author = {Gina A. Adams and Diana H. Wall} } @article {1475, title = {Biodiversity and Ecosystem Functioning}, journal = {Bioscience}, year = {1999}, pages = {107-108}, keywords = {LTER-MCM}, doi = {LTER}, author = {Diana H. Wall} }