02735nas a2200325 4500008004100000022001400041245008600055210006900141260001200210490000700222520179000229653001502019653001302034653001002047653002202057653001002079100002602089700002402115700002502139700002102164700001802185700002502203700002102228700002202249700001902271700002402290700002102314700001702335856005702352 2025 eng d a0722-406000aA comprehensive survey of soil microbial diversity across the Antarctic continent0 acomprehensive survey of soil microbial diversity across the Anta c02/20250 v483 a

Antarctic soils are unique from those found nearly anywhere else on Earth yet can still harbor a broad diversity of microorganisms able to tolerate the challenging conditions typical of the continent. For these reasons, microbiologists have been drawn to Antarctica for decades. However, our understanding of which microbes thrive in Antarctic soils and how they to do so remains limited. To help resolve these knowledge gaps, we analyzed a collection of 200 archived Antarctic soils—from Livingston Island on the Antarctic Peninsula to Cape Hallett in northern Victoria Land. We analyzed the prokaryotic and fungal communities in these soils using both cultivation-independent marker gene sequencing and cultivation-dependent approaches (microbial isolation), paired with extensive soil geochemical analyses. Our cultivation-independent analyses indicate that colder, saltier, and drier soils harbor less diverse communities of bacteria and fungi, distinct from those found in soils with less challenging conditions. We also built a culture collection from a subset of these soils that encompasses more than 50 bacterial and fungal genera, including cold-tolerant organisms, such as <i>Cryobacterium</i> and <i>Cryomyces</i>. By directly comparing the diversity of our cultured isolates against our cultivation-independent data, we show that many of the more abundant Antarctic taxa are not readily cultivated and highlight bacterial and fungal taxa that should be the focus of future cultivation efforts. Together, we hope that our collection of isolates, the comprehensive data compiled from the cultivation-independent analyses, and our geochemical analyses will serve as a community resource to accelerate the study of Antarctic soil microbes.

10aAntarctica10abacteria10afungi10amicrobial ecology10asoils1 aDragone, Nicholas, B.1 aChildress, Mary, K.1 aVanderburgh, Caihong1 aWillmore, Rachel1 aHogg, Ian, D.1 aSancho, Leopoldo, G.1 aLee, Charles, K.1 aBarrett, John, E.1 aQuandt, Alisha1 aLeMonte, Joshua, J.1 aAdams, Byron, J.1 aFierer, Noah uhttps://link.springer.com/10.1007/s00300-025-03372-y02394nas a2200301 4500008004100000022001400041245012200055210006900177260001200246300001100258490000800269520142600277653001501703653002401718653001901742653001901761653003401780653002301814100002801837700002001865700002501885700002401910700002201934700002101956700001901977700002101996856007502017 2025 eng d a0012-965800aRemote sensing for species distribution models: An illustration from a sentinel taxon of the world's driest ecosystem0 aRemote sensing for species distribution models An illustration f c02/2025 ae700350 v1063 a

In situ observed data are commonly used as species occurrence response variables in species distribution models. However, the use of remotely observed data from high-resolution multispectral remote-sensing images as a source of presence/absence data for species distribution models remains under-developed. Here, we describe an ensemble species distribution model of black microbial mats (Nostoc spp.) using presence/absence points derived from the unmixing of 4-m resolution WorldView-2 and WorldView-3 images in the Lake Fryxell basin region of Taylor Valley, Antarctica. Environmental and topographical characteristics such as soil moisture, snow, elevation, slope, and aspect were used as predictor variables in our models. We demonstrate that we can build and run ensemble species distribution models using both dependent and independent variables derived from remote-sensing data to generate spatially explicit habitat suitability maps. Snow and soil moisture were found to be the most important variables accounting for about 80% of the variation in the distribution of black mats throughout the Fryxell basin. This study highlights the potential contribution of high-resolution remote-sensing to species distribution modeling and informs new studies incorporating remotely derived species occurrences in species distribution models, especially in remote areas where access to in situ data is often limited.

10aAntarctica10aMcMurdo Dry Valleys10amicrobial mats10aremote sensing10aspecies distribution modeling10aspecies occurrence1 aThapa‐Magar, Khum, B.1 aSokol, Eric, R.1 aGooseff, Michael, N.1 aSalvatore, Mark, R.1 aBarrett, John, E.1 aLevy, Joseph, S.1 aKnightly, Paul1 aPower, Sarah, N. uhttps://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecy.7003503255nas a2200277 4500008004100000022001300041245011100054210006900165260001200234300001100246520240400257653001502661653001302676653001102689653002902700653000902729653001702738100002102755700002402776700002002800700002102820700002502841700001702866700002202883856007202905 2024 eng d a2666017200aRemotely characterizing photosynthetic biocrust in snowpack-fed microhabitats of Taylor Valley, Antarctica0 aRemotely characterizing photosynthetic biocrust in snowpackfed m c02/2024 a1001203 a

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.

10aAntarctica10abiocrust10acarbon10areflectance spectroscopy10asnow10asoil ecology1 aPower, Sarah, N.1 aSalvatore, Mark, R.1 aSokol, Eric, R.1 aStanish, Lee, F.1 aBorges, Schuyler, R.1 aAdams, Byron1 aBarrett, John, E. uhttps://www.sciencedirect.com/science/article/pii/S266601722400004X02597nas a2200229 4500008004100000245011900041210006900160260001200229520184900241653001502090653001802105653002602123653000902149653001502158653001902173100002102192700002402213700002002237700002102257700002202278856006702300 2020 eng d00aEstimating microbial mat biomass in the McMurdo Dry Valleys, Antarctica using satellite imagery and ground surveys0 aEstimating microbial mat biomass in the McMurdo Dry Valleys Anta c09/20203 a

Cyanobacterial mat communities are the main drivers of primary productivity in the McMurdo Dry Valleys, Antarctica. These microbial communities form laminar mats on desert pavement surfaces adjacent to glacial meltwater streams, ponds, and lakes. The low-density nature of these communities and their patchy distribution make assessments of distribution, biomass, and productivity challenging. We used satellite imagery coupled with in situ surveying, imaging, and sampling to systematically estimate microbial mat biomass in selected wetland regions in Taylor Valley, Antarctica. On January 19th, 2018, the WorldView-2 multispectral satellite acquired an image of our study areas, where we surveyed and sampled seven 100 m2 plots of microbial mats for percent ground cover, ash-free dry mass (AFDM), and pigment content (chlorophyll-a, carotenoids, and scytonemin). Multispectral analyses revealed spectral signatures consistent with photosynthetic activity (relatively strong reflection at near-infrared wavelengths and relatively strong absorption at visible wavelengths), with average normalized difference vegetation index (NDVI) values of 0.09 to 0.28. Strong correlations of microbial mat ground cover (R2 = 0.84), biomass (R2 = 0.74), chlorophyll-a content (R2 = 0.65), and scytonemin content (R2 = 0.98) with logit transformed NDVI values demonstrate that satellite imagery can detect both the presence of microbial mats and their key biological properties. Using the NDVI—biomass correlation we developed, we estimate carbon (C) stocks of 21,715 kg (14.7 g C m−2) in the Canada Glacier Antarctic Specially Protected Area, with an upper and lower limit of 74,871 and 6312 kg of C, respectively.

10aAntarctica10amicrobial mat10amultispectral imagery10aNDVI10aNostocales10aremote sensing1 aPower, Sarah, N.1 aSalvatore, Mark, R.1 aSokol, Eric, R.1 aStanish, Lee, F.1 aBarrett, John, E. uhttps://link.springer.com/article/10.1007%2Fs00300-020-02742-y03261nas a2200241 4500008004100000245013300041210006900174260001200243490000600255520247400261653001502735653002202750653001402772653001102786653001902797100002002816700002202836700002202858700002402880700002402904700002102928856007002949 2020 eng d00aEvaluating alternative metacommunity hypotheses for diatoms in the McMurdo Dry Valleys using simulations and remote sensing data0 aEvaluating alternative metacommunity hypotheses for diatoms in t c09/20200 v83 a

Diatoms are diverse and widespread freshwater Eukaryotes that make excellent microbial subjects for addressing questions in metacommunity ecology. In the McMurdo Dry Valleys of Antarctica, the simple trophic structure of glacier-fed streams provides an ideal outdoor laboratory where well-described diatom assemblages are found within two cyanobacterial mat types, which occupy different habitats and vary in coverage within and among streams. Specifically, black mats of Nostoc spp. occur in marginal wetted habitats, and orange mats (Oscillatoria spp. and Phormidium spp.) occur in areas of consistent stream flow. Despite their importance as bioindicators for changing environmental conditions, the role of dispersal in structuring dry valley diatom metacommunities remains unclear. Here, we use MCSim, a spatially explicit metacommunity simulation package for R, to test alternative hypotheses about the roles of dispersal and species sorting in maintaining the biodiversity of diatom assemblages residing in black and orange mats. The spatial distribution and patchiness of cyanobacterial mat habitats was characterized by remote imagery of the Lake Fryxell sub-catchment in Taylor Valley. The available species pool for diatom metacommunity simulation scenarios was informed by the Antarctic Freshwater Diatoms Database, maintained by the McMurdo Dry Valleys Long Term Ecological Research program. We used simulation outcomes to test the plausibility of alternative community assembly hypotheses to explain empirically observed patterns of freshwater diatom biodiversity in the long-term record. The most plausible simulation scenarios suggest species sorting by environmental filters, alone, was not sufficient to maintain biodiversity in the Fryxell Basin diatom metacommunity. The most plausible scenarios included either (1) neutral models with different immigration rates for diatoms in orange and black mats or (2) species sorting by a relatively weak environmental filter, such that dispersal dynamics also influenced diatom community assembly, but there was not such a strong disparity in immigration rates between mat types. The results point to the importance of dispersal for understanding current and future biodiversity patterns for diatoms in this ecosystem, and more generally, provide further evidence that metacommunity theory is a useful framework for testing hypotheses about microbial community assembly.

10aAntarctica10aBacillariophyceae10adispersal10aNostoc10astream ecology1 aSokol, Eric, R.1 aBarrett, John, E.1 aKohler, Tyler, J.1 aMcKnight, Diane, M.1 aSalvatore, Mark, R.1 aStanish, Lee, F. uhttps://www.frontiersin.org/article/10.3389/fevo.2020.521668/full