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Glacial retreat due to global warming is exposing large tracts of barren glacial sediments that are quickly colonized by CO2-fixing microbial communities that can constitute the climax community in many high-Arctic, alpine, and Antarctic environments. Despite the potential importance of these processes, little is known about microbial community successional dynamics and rates of carbon (C) sequestration in environments where higher plants are slow or unable to establish. We analyzed microbial community succession and C and N accumulation in newly exposed sediments along an Antarctic glacial chronosequence where moss and microbial autotrophs are the dominant primary producers. During the first 4 years of succession (0 to 40 m from the glacier) algae were the most relatively abundant eukaryotes, but by the second phase studied (8 to 12 years) moss amplicon sequence variants (ASVs) dominated. The rise in moss coincided with a significant buildup of C and N in the sediments. The final two phases of the successional sequence (16 to 20 and 26 to 30 years) were marked by declines in microbial species richness and moss relative abundance, that coincided with significant decreases in both total C and N. These retrogressive declines coincided with a large increase in abundance of predatory Vampyrellidae suggesting a possible mechanism for retrogression in this and perhaps other terrestrial ecosystems at the edge of the cryosphere. These findings have implications for understanding CO2 sequestration and ecosystem succession in microbial-dominated regions of the cryobiosphere where large tracts of land are currently undergoing deglaciation. 

With the shift to remote learning during the COVID-19 pandemic, educators turned to remote exam proctoring software to support integrity for online tests. However, due to the mechanisms used to surveil test-takers, these systems come with significant privacy and security tradeoffs. At the height of the pandemic, Balash et al. (SOUPS ’21) found that test-takers had privacy concerns with remote proctoring but acquiesced due to a number of factors. We investigate how perceptions have changed four years later. To gain a fuller perspective on how users experience these tools now, we replicate Balash et al.’s study with 127 participants who have experienced exam proctoring. We found a significant shift in favor of proctoring software, with greater acceptance of all monitoring methods compared to 2020. This is likely due to the convenience of remote exams and a growing resignation to privacy trade-offs. We discuss these implications and suggest future directions. 

We combined field observations and microcosm experiments on recently deglaciated proglacial soils from Midtre Lovénbreen, Svalbard. Geochemical analyses suggest stronger limitation by nitrogen (N) and phosphorus (P) than by carbon (C). To distinguish between N and P limitation, we caried out microcosm incubations. In +N+P microcosms there was a bloom of rapidly growing soil algae and predatory bacteria resulting in significant shifts in microbial community structure. Addition of P decreased the C:N ratio, changed the structure of the prokaryotic community, and increased the growth of soil algae, mosses, and N-fixing cyanobacteria. Overall, these results indicate that P availability limits the establishment of early microbial primary producers. Given the rapid deglaciation of High Arctic regions, these findings highlight the central role of P in structuring these emerging ecosystems. 

The files contain MetaData (soil temperatures and light flux data) for the period of August 2023 thrugh August of 2025.  The data are from sites 1 and 2 as described in the following papers:   Schmidt SK, MA Cramm, AJ Solon et al. 2025. Biological soil crust microcolonies reveal how microbial communities assemble following retreat of a High Arctic glacier. FEMS Microbes xtaf007. Cimpoiasu MO, O Kuras, H Harrison, et al. 2025. High-resolution 4D electrical resistivity tomography and below-ground point sensor monitoring of High Arctic deglaciated sediments capture zero-curtain effects, freeze–thaw transitions, and mid-winter thawing. The Cryosphere 19: 401–421 Cimpoiasu MO, O Kuras, H Harrison, et al. 2024. Characterization of a deglaciated sediment chronosequence in the High Arctic using near‐surface geoelectrical monitoring methods. Permafrost and Periglacial Processes 35: 157-171. https://doi.org/10.1002/ppp.2220 

High-performance optical interference coatings have transformed precision interferometry and spectroscopy by enabling unparalleled control over light–matter interactions. This review explores recent innovations in ion-beam sputtered amorphous dielectric, as well as substrate-transferred crystalline coatings, and their impact on systems at the forefront of precision metrology. These state-of-the-art coating techniques generate multilayers with ultralow optical losses, yielding mirrors with exceptional reflectivity. Refinements in their noise performance push the ultimate limits of sensitivity, resolution, and stability in demanding laser-based metrology applications. These technologies underpin the most advanced timekeeping and spatial measurement tools, enabling high-finesse reference cavities for the world’s most precise optical atomic clocks and low-noise reflective test masses for km-baseline gravitational-wave detectors. Emerging hybrid designs combining these techniques expand access to the mid-infrared spectral region, enabling the first ultralow-optical-loss coatings in the 3000–5000 nm wavelength range for enhanced spectroscopy and trace-gas detection. We highlight how these technologies redefine coating performance metrics and set new benchmarks in quantum science, fundamental physics, and precision optical sensing. 

Human-subjects researchers are increasingly expected to de-identify and publish data about research participants. However, de-identification is difficult, lacking objective solutions for how to balance privacy and utility, and requiring significant time and expertise. To understand researchers' approaches, we interviewed 18 practitioners who have de-identified data for publication and 6 curators who review data submissions for repositories and funding organizations. We find that researchers account for the kinds of risks described by k-anonymity, but they address them through manual and social processes and not through systematic assessments of risk across a dataset. This allows for nuance but may leave published data vulnerable to re-identification. We explore why researchers take this approach and highlight three main barriers to more rigorous de-identification: threats seem unrealistic, stronger standards are not incentivized or supported, and tools do not meet researchers' needs. We conclude with takeaways for repositories, funding agencies, and privacy experts.