Liu, W. P. A. | Search bioRxiv

bioRxiv2026

Revealing the Widespread Bias of Extinction Risk in the Antarctic and the Southern Ocean

Accelerating environmental change in the Antarctic and Southern Ocean (ASO) necessitates robust extinction risk assessments to inform conservation priorities and track progress towards global biodiversity targets. Nevertheless, no systematic, region-wide baseline of extinction risk currently exists for tracking ASO biodiversity responses to ongoing change, a significant barrier to global biodiversity monitoring. Here, we present the first comprehensive synthesis of extinction risk knowledge spanning plants, animals, and fungi across the ASO, examining biases in current assessments, the distribution of Threatened species and their associated threats. In the absence of a complete regional species checklist, species were compiled from >6,800,000 occurrences and existing checklists, yielding 5,403 assessments representing 2,806 species using a data-inclusive workflow that increased available assessments by over three-fold. Assessments are heavily biased towards vertebrates (56% assessed), while invertebrates, despite their ecological prevalence, are markedly underrepresented (4% assessed). Among vertebrates, mammals have the highest proportion of Threatened species (35%), while ASO birds are disproportionately Threatened (27%) compared to the global average (12%) with the greatest threat for ASO species being Biological Resource Use. Despite more Threatened species in the sub-Antarctic islands and the Antarctic Peninsula, relative to assessment effort, these regions had fewer Threatened species than expected, indicating these areas may function as refugia. These pronounced assessment biases highlight the need for more balanced, representative, and data-inclusive extinction risk assessments to be able to effectively detect conservation status change. This work represents an important step in ensuring ASO representation in global biodiversity monitoring frameworks strengthening the capacity of these frameworks to detect, attribute, and respond to future biodiversity changes.

ecology↗

bioRxiv2025

Resilient Antarctic soil bacteria consume trace gases across wide temperature ranges

Polar desert soils host diverse microbial communities despite limited nutrients and frequent temperature and light fluctuations. Adapting to these extremes, most bacteria possess high-affinity hydrogenases and carbon monoxide dehydrogenases, enabling them to use atmospheric trace gases such as hydrogen (H2) and carbon monoxide (CO) to generate energy and fix carbon. Despite the foundational importance of this process in polar desert ecosystems, little is known about the thermal sensitivity of trace gas oxidation or how this process will respond to climate warming. Here, we show through in situ and ex situ incubations that H2 consumption is an exceptionally thermally resilient process that can occur from -20 to +75{degrees}C, at rates comparable to temperate ecosystems (peaking at 8.56 nmol H2 h-1 g dry soil-1 at 25{degrees}C). Temperature ranges of CO (-20 to 42{degrees}C) and CH4 (-20 to 30{degrees}C) oxidation are also wider than expected, though the pattern of thermal sensitivity conforms with general theory. Metagenomic analyses support these data, revealing that atmospheric H2 and CO oxidisers are widespread, diverse, and abundant, and suggesting most Antarctic bacteria function below their temperature optima for these processes. Modelling of seasonal temperatures across ice-free Antarctica under current and future emissions scenarios indicates that H2 and CO oxidation can occur year-round, increasing by up to 35% or 44%, respectively, by 2100. Our results indicate constitutive aerotrophic activity contributing to Antarctic ecosystem functioning and biodiversity across spatial and temporal scales, with further studies required to understand how it interacts with photosynthesis in a changing climate.

microbiology↗