03241nas a2200505 4500008004100000022001400041245010400055210006900159260001200228300001800240490000700258520177600265653001502041653001302056653001402069653001302083653001902096100002202115700001802137700001602155700002402171700002302195700002302218700001502241700002202256700001802278700002202296700002302318700002402341700002202365700001902387700002302406700001302429700002302442700002102465700002702486700002402513700002302537700001402560700002602574700002002600700003102620700001502651856006902666 2025 eng d a0043-139700aOne-hundred fundamental, open questions to integrate methodological approaches in lake ice research0 aOnehundred fundamental open questions to integrate methodologica c05/2025 ae2024WR0390420 v613 a

The rate of technological innovation within aquatic sciences outpaces the collective ability of individual scientists within the field to make appropriate use of those technologies. The process of in situ lake sampling remains the primary choice to comprehensively understand an aquatic ecosystem at local scales; however, the impact of climate change on lakes necessitates the rapid advancement of understanding and the incorporation of lakes on both landscape and global scales. Three fields driving innovation within winter limnology that we address here are autonomous real-time in situ monitoring, remote sensing, and modeling. The recent progress in low-power in situ sensing and data telemetry allows continuous tracing of under-ice processes in selected lakes as well as the development of global lake observational networks. Remote sensing offers consistent monitoring of numerous systems, allowing limnologists to ask certain questions across large scales. Models are advancing and historically come in different types (process-based or statistical data-driven), with the recent technological advancements and integration of machine learning and hybrid process-based/statistical models. Lake ice modeling enhances our understanding of lake dynamics and allows for projections under future climate warming scenarios. To encourage the merging of technological innovation within limnological research of the less-studied winter period, we have accumulated both essential details on the history and uses of contemporary sampling, remote sensing, and modeling techniques. We crafted 100 questions in the field of winter limnology that aim to facilitate the cross-pollination of intensive and extensive modes of study to broaden knowledge of the winter period.

10acryosphere10alake ice10alimnology10amodeling10aremote sensing1 aCulpepper, Joshua1 aSharma, Sapna1 aGunn, Grant1 aMagee, Madeline, R.1 aMeyer, Michael, F.1 aAnderson, Eric, J.1 aArp, Chris1 aCooley, Sarah, W.1 aDolan, Wayana1 aDugan, Hilary, A.1 aDuguay, Claude, R.1 aJones, Benjamin, M.1 aKirillin, Georgiy1 aLadwig, Robert1 aLeppäranta, Matti1 aLong, Di1 aMagnuson, John, J.1 aPavelsky, Tamlin1 aPiccolroaz, Sebastiano1 aRobertson, Dale, M.1 aSteele, Bethel, G.1 aTom, Manu1 aWeyhenmeyer, Gesa, A.1 aWoolway, Iestyn1 aXenopoulos, Marguerite, A.1 aYang, Xiao uhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024WR03904202394nas 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.7003504374nas a2200193 4500008004100000245011900041210006900160260005800229490000900287520367400296653002603970653002403996653002904020653001604049653001904065100002704084700002204111856004704133 2025 eng d00aThe temporal and spatial dynamics of surface sediment on the permanently frozen lakes of Taylor Valley, Antarctica0 atemporal and spatial dynamics of surface sediment on the permane aMadison, WIbUniversity of Wisconsin-Madisonc05/20250 vM.S.3 a

The McMurdo Dry Valleys are the largest unglaciated region of Antarctica and are home to some of the only perennially frozen lakes in the world. The ice covers of the Taylor Valley lakes are subject to decadal-length fluctuations in thickness, largely ranging between three and five meters thick. It has been hypothesized that the changes in ice cover thickness are due to a combination of climate factors and lake ice surface characteristics, but as of yet there have been no studies focusing on interannual dynamics of lake ice albedo by leveraging remote sensing datasets. Landsat 8 imagery was manipulated using spectral mixture analysis to find the abundance of sediment cover across three different Taylor Valley lakes from 2016-2024 during the sunlit period of the year. Peak sediment coverage was not synchronous across years, with Lake Hoare peaking the earliest in 2021, followed by East Lake Bonney and Lake Fryxell in 2023. West Lake Bonney had no apparent peak, although concentrations have declined since 2021. Overall sediment abundance values across all lakes ranged from near 0% to over 75%, though each lake has a different level of sediment coverage. Lake Fryxell and Lake Hoare had the highest mean sediment concentrations, followed by East Lake Bonney, then West Lake Bonney. The relationship between ice thickness and sediment coverage was strongest at Lake Fryxell, followed by East Lake Bonney. Lake Hoare and West Lake Bonney appear to have weaker links between ice thickness and surface sediment, likely driven by differences in overall sediment cover and shading from the surrounding landscape. Ice surface albedo is a historically understudied component of ice physical structure and thermal mechanics and should be more closely considered in future studies predicting ice thickness in the McMurdo Dry Valleys, especially in cases to predict total ice loss. Permanently frozen lakes exhibit unique ice dynamics compared to seasonally freezing lakes, due to their consistent lake ice, where previous years ice conditions have a large effect on ice into the future. The McMurdo Dry Valleys (MDVs), a large unglaciated region in Antarctica, contain many of the few permanently frozen lakes that exist globally. Albedo is a critical factor influencing lake ice mass balance and may strongly govern lake ice thickness. Changes in surface albedo on MDVs lakes occur as a result of aeolian sediment deposition from the surrounding bare soil landscape or physical changes in ice quality throughout the summer, like ice whitening. To investigate the importance of surface characteristics of Taylor Valley lake ice, a one-dimensional thermal diffusion model was developed using in situ meteorological data and a satellite derived ice albedo estimates to simulate ice thickness on East Lake Bonney, Antarctica. Ice thickness was modeled from late 2016 through 2024 using a novel ice albedo dataset, derived from Landsat 8 imagery using linear spectral mixture analysis. Estimated albedo values ranged from 0.5-0.85, covering years when sediment cover was very heavy to very low. Modeled ice thickness was strongly correlated with measured thicknesses. For the period of the year where manual ice thickness measurements are made, modeled ice thicknesses ranged between 2.92-4.16 m, where measured values for that same time span ranged between 3.06-4.19 m. When either increasing or decreasing albedo by 5-10%, mean ice thicknesses diverged by up to 0.8 m. Ice thicknesses are strongly influenced by surface sediment concentrations, and the contribution of a tailored albedo dataset was a valuable input that has historically been over-simplified.

10aaeolian geomorphology10aMcMurdo Dry Valleys10apermanently frozen lakes10apolar lakes10aremote sensing1 aDougherty, Charles, E.1 aDugan, Hilary, A. uhttp://digital.library.wisc.edu/1793/9519402546nas a2200241 4500008004100000022001400041245007500055210006900130260001200199490000700211520184500218653001302063653001102076653001202087653002402099653001902123653001702142100002102159700002402180700002402204700002202228856005402250 2024 eng d a2045-775800aHabitat suitability of biocrust communities in a cold desert ecosystem0 aHabitat suitability of biocrust communities in a cold desert eco c07/20240 v143 a

Drylands are unique among terrestrial ecosystems in that they have a significant proportion of primary production facilitated by non-vascular plants such as colonial cyanobacteria, moss, and lichens, i.e., biocrusts, which occur on and in the surface soil. Biocrusts inhabit all continents, including Antarctica, an increasingly dynamic continent on the precipice of change. Here, we describe in-situ field surveying and sampling, remote sensing, and modeling approaches to assess the habitat suitability of biocrusts in the Lake Fryxell basin of Taylor Valley, Antarctica, which is the main site of the McMurdo Dry Valleys Long-Term Ecological Research Program. Soils suitable for the development of biocrusts are typically wetter, less alkaline, and less saline compared to unvegetated soils. Using random forest models, we show that gravimetric water content, electrical conductivity, and snow frequency are the top predictors of biocrust presence and biomass. Areas most suitable for the growth of dense biocrusts are soils associated with seasonal snow patches. Using geospatial data to extrapolate our habitat suitability model to the whole basin predicts that biocrusts are present in 2.7 × 105 m2 and contain 11–72 Mg of aboveground carbon, based on the 90% probability of occurrence. Our study illustrates the synergistic effect of combining field and remote sensing data for understanding the distribution and biomass of biocrusts, a foundational community in the carbon balance of this region. Extreme weather events and changing climate conditions in this region, especially those influencing snow accumulation and persistence, could have significant effects on the future distribution and abundance of biocrusts and therefore soil organic carbon storage in the McMurdo Dry Valleys.

10abiocrust10acarbon10adryland10ahabitat suitability10aremote sensing10asoil ecology1 aPower, Sarah, N.1 aThomas, Valerie, A.1 aSalvatore, Mark, R.1 aBarrett, John, E. uhttps://onlinelibrary.wiley.com/toc/20457758/14/702567nas a2200337 4500008004100000245010300041210006900144260001200213300000900225490000700234520158600241653001601827653001201843653001401855653001901869653001801888100002401906700002201930700002401952700002001976700002101996700002102017700002502038700002102063700002102084700001902105700002102124700001702145700002102162856004602183 2023 eng d00aThe distribution of surface soil moisture over space and time in eastern Taylor Valley, Antarctica0 adistribution of surface soil moisture over space and time in eas c06/2023 a31700 v153 a

Available soil moisture is thought to be the limiting factor for most ecosystem processes in the cold polar desert of the McMurdo Dry Valleys (MDVs) of Antarctica. Previous studies have shown that microfauna throughout the MDVs are capable of biological activity when sufficient soil moisture is available (~2–10% gravimetric water content), but few studies have attempted to quantify the distribution, abundance, and frequency of soil moisture on scales beyond that of traditional field work or local field investigations. In this study, we present our work to quantify the soil moisture content of soils throughout the Fryxell basin using multispectral satellite remote sensing techniques. Our efforts demonstrate that ecologically relevant abundances of liquid water are common across the landscape throughout the austral summer. On average, the Fryxell basin of Taylor Valley is modeled as containing 1.5 ± 0.5% gravimetric water content (GWC) across its non-fluvial landscape with ~23% of the landscape experiencing an average GWC > 2% throughout the study period, which is the observed limit of soil nematode activity. These results indicate that liquid water in the soils of the MDVs may be more abundant than previously thought, and that the distribution and availability of liquid water is dependent on both soil properties and the distribution of water sources. These results can also help to identify ecological hotspots in the harsh polar Antarctic environment and serve as a baseline for detecting future changes in the soil hydrological regime.

10aDry valleys10aecology10ahydrology10aremote sensing10asoil moisture1 aSalvatore, Mark, R.1 aBarrett, John, E.1 aFackrell, Laura, E.1 aSokol, Eric, R.1 aLevy, Joseph, S.1 aKuentz, Lily, C.1 aGooseff, Michael, N.1 aAdams, Byron, J.1 aPower, Sarah, N.1 aKnightly, Paul1 aMatul, Haley, M.1 aSzutu, Brian1 aDoran, Peter, T. uhttps://www.mdpi.com/2072-4292/15/12/317002175nas a2200229 4500008004100000022001400041245022200055210006900277260001200346300001400358490000700372520135100379653001501730653001601745653001901761653001601780653001201796100002101808700002101829700002401850856007101874 2022 eng d a1523-043000aTiming and duration of ephemeral Antarctic water tracks and wetlands using high temporal–resolution satellite imagery, high spatial–resolution satellite imagery, and ground-based sensors in the McMurdo Dry Valleys0 aTiming and duration of ephemeral Antarctic water tracks and wetl c12/2022 a538 - 5610 v543 a

Antarctic water tracks and ephemeral wetlands are a primary location for biogeochemical soil processes driving cold desert soil formation. Though the spatial extent of water tracks and wetted soils has been mapped in the McMurdo Dry Valleys (MDV) on the basis of mapping darkened pixels in high-resolution commercial satellite imagery, the timescale over which water tracks and wetlands form and the duration of these biogeochemically active environments remain unknown. Here, we determine the start date and end dates and the duration of wetted soils at ten sites located across the MDV using a combination of in situ soil sensors and two complementary remote imaging platforms (Planet and WorldView) to understand the hydroclimatic processes that drive water track and wetland formation. Our remote sensing employs a terrain correction workflow that removes the contribution of differential direct illumination and small-scale shadowing on pixel brightness, reducing false positives (soils identified as wetted when in fact they are shadowed or darkened as a consequence of high phase angle). Our findings extend the water track and wetland hydroperiod by over a month, showing darkening occurring from November to March, suggesting hydrological contributions from ground ice thaw, snowmelt, and salt deliquescence and soil brine growth.

10aAntarctica10ahydroperiod10aremote sensing10awater track10awetland1 aKuentz, Lily, C.1 aLevy, Joseph, S.1 aSalvatore, Mark, R. uhttps://www.tandfonline.com/doi/full/10.1080/15230430.2022.212385802093nas a2200205 4500008004100000022001400041245013400055210006900189260001200258300000900270520139200279653001801671653001401689653001701703653002101720653001301741653001901754100002101773856009301794 2021 eng d a0954-102000aEpisodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica0 aEpisodic basinscale soil moisture anomalies associated with high c08/2021 a1-153 a

Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of < 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.

10adeliquescence10ahydrology10amicroclimate10amicrometeorology10apedology10aremote sensing1 aLevy, Joseph, S. uhttps://www.cambridge.org/core/product/identifier/S0954102021000341/type/journal_article02597nas 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-y02051nas a2200253 4500008004100000245010800041210006900149260001200218520110900230653001201339653001401351653002401365653001701389653001901406653001701425100002401442700002501466700002201491700002001513700002101533700002101554700001601575856020601591 2020 eng d00aRemote characterization of photosynthetic communities in the Fryxell basin of Taylor Valley, Antarctica0 aRemote characterization of photosynthetic communities in the Fry c03/20203 a

We investigate the spatial distribution, spectral properties and temporal variability of primary producers (e.g. communities of microbial mats and mosses) throughout the Fryxell basin of Taylor Valley, Antarctica, using high-resolution multispectral remote-sensing data. Our results suggest that photosynthetic communities can be readily detected throughout the Fryxell basin based on their unique near-infrared spectral signatures. Observed intra- and inter-annual variability in spectral signatures are consistent with short-term variations in mat distribution, hydration and photosynthetic activity. Spectral unmixing is also implemented in order to estimate mat abundance, with the most densely vegetated regions observed from orbit correlating spatially with some of the most productive regions of the Fryxell basin. Our work establishes remote sensing as a valuable tool in the study of these ecological communities in the McMurdo Dry Valleys and demonstrates how future scientific investigations and the management of specially protected areas could benefit from these tools and techniques.

10aecology10ahydrology10aMcMurdo Dry Valleys10amicrobiology10aremote sensing10aspectroscopy1 aSalvatore, Mark, R.1 aBorges, Schuyler, R.1 aBarrett, John, E.1 aSokol, Eric, R.1 aStanish, Lee, F.1 aPower, Sarah, N.1 aMorin, Paul uhttps://www.cambridge.org/core/journals/antarctic-science/article/remote-characterization-of-photosynthetic-communities-in-the-fryxell-basin-of-taylor-valley-antarctica/8576F6BB1BCFDCA8409F5EA96CA00C6F