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Abstract Elemental sulfur (S₈⁰)‐oxidising Sulfolobales (Archaea) dominate high‐temperature acidic hot springs (>80°C, pH <4). However, genomic analyses of S₈⁰‐oxidising members of the Sulfolobales reveal a patchy distribution of genes encoding sulfur oxygenase reductase (SOR), an S₈⁰disproportionating enzyme attributed to S₈⁰oxidation. Here, we report the S₈⁰‐dependent growth of two Sulfolobales strains previously isolated from acidic hot springs in Yellowstone National Park, one of which associated with bulk S₈⁰during growth and one that did not. The genomes of each strain encoded different sulfur metabolism enzymes, with only one encoding SOR. Dialysis membrane experiments showed that direct contact is not required for S₈⁰oxidation in the SOR‐encoding strain. This is attributed to the generation of hydrogen sulfide (H₂S) from S₈⁰disproportionation that can diffuse out of the cell to solubilise bulk S₈⁰to form soluble polysulfides (S_x²⁻) and/or S₈⁰nanoparticles that readily diffuse across dialysis membranes. The Sulfolobales strain lacking SOR required direct contact to oxidise S₈⁰, which could be overcome by the addition of H₂S. High concentrations of S₈⁰inhibited the growth of both strains. These results implicate alternative strategies to acquire and metabolise sulfur in Sulfolobales and have implications for their distribution and ecology in their hot spring habitats. 

Abstract The withdrawal of glaciers in mountainous systems exposes over‐steepened slopes previously sculpted by ice. This debuttressing can directly trigger mass movements or leave slopes susceptible to them by other drivers, including seismogenic shaking and changing climate conditions. These systems may pose hazards long after deglaciation. Here, we investigate the drivers of slope failure for landslides at the northern entrance to Yellowstone National Park, a critical conduit traversed by ~1 million visitors each year. Through field mapping and analyses of LiDAR data, we quantify the spatial and temporal relationships between eight adjacent slides. Stratigraphic relationships and surface roughness analyses suggest initial emplacement 13–11.5 ka, after a significant delay from Deckard Flats glacial retreat (15.1 ± 1.2 ka). Thus, rapid glacial debuttressing was not the direct trigger of slope failure, though the resultant change in stress regime likely had a preparatory influence. We posit that the timing of failure was associated with (1) a period of enhanced moisture and seismicity in the late Pleistocene and (2) altered stress regimes associated with ice retreat. Historical archives and cross‐cutting relationships indicate portions of some ancient slides were reactivated; these areas are morphologically distinguishable from other slide surfaces, with mean topographic roughness 2 times that of non‐active slides. Stream power analysis and archival records indicate Holocene incision of the Gardner River and human disturbances are largely responsible for modern reactivations. Our findings highlight the importance of combining archival records with stratigraphic, field and remote sensing approaches to understanding landslide timing, risk, and drivers in post‐glacial environments. This study also provides a valuable baseline for geomorphic change in the Yellowstone system, where a 2022 flood incised streams, damaged infrastructure and further reactivated landslide slopes. 

Abstract Large carnivores such as the lion are declining across Africa, in part because their large herbivore prey is declining. There is consensus that increased protection from prey depletion will be necessary to reverse the decline of lion populations, but few studies have tested whether increased protection is sufficient to reverse the decline, particularly in the large, open ecosystems where most lions remain. Here, we used an integrated population model to test whether lion demography and population dynamics were measurably improved by increased protection. We used data from monitoring of 358 individuals from 2013 to 2021 in the Greater Kafue Ecosystem, where prior research showed that lions were strongly limited by prey depletion, but protection increased in several well‐defined areas beginning in 2018. In some other areas, protection decreased. In areas with high protection, lion fecundity was 29% higher, and mean annual apparent survival (φ) was 8.3% higher (with a minimum difference of 6.0% for prime‐aged adult females and a maximum difference of 11.9% for sub‐adult males). These demographic benefits combined to produce likely population growth in areas with high protection ( = 1.085, 90% CI = 0.97, 1.21), despite likely population decline in areas with low protection ( = 0.970, 90% CI = 0.88, 1.07). For the ecosystem as a whole, population size remained relatively constant at a moderate density of 3.74 (±0.49 SD) to 4.13 (±0.52 SD) lions/100 km². With the growth observed in areas with high protection, the expected doubling time was 10 years. Despite this, recovery at the scale of the entire ecosystem is likely to be slow without increased protection; the current growth rate would require 50 years to double. Our results demonstrate that increased protection is likely to improve the reproduction and population growth rate of lions at a large scale within an unfenced ecosystem that has been greatly affected by poaching. 

Abstract Reliable predictions of ectotherm responses to climatic warming are important because many of these organisms perform important roles that can directly impact human society.Thermal performance curves (TPCs) provide useful information on the physiological constraints that limit the capacity of these temperature‐sensitive organisms to exist and grow.NLS pipelines for fitting TPCs are widely available, but these approaches rely on assumptions that can yield unreliable parameter estimates.We presentbayesTPC, anRpackage for fitting TPCs to trait responses using thenimblelanguage and machinery as the underlying engine for Markov Chain Monte Carlo.bayesTPCaims to support the adoption of Bayesian approaches in thermal physiology, and promote TPC fitting that adequately quantifies uncertainty. 

Abstract The molecular complexes described herein use main‐group elements or transition metals to control the stoichiometric cleavage of N−H bonds of ammonia (NH₃) and/or catalyze chemical and electrochemical NH₃oxidation to dinitrogen (N₂). We highlight the phenomenon of coordination‐induced bond weakening and a variety of N−H bond cleavage mechanisms of NH₃including H atom abstraction, inter‐ and intra‐molecular deprotonation reactions, oxidative addition, andσ‐bond metathesis that have been demonstrated with molecular systems. We provide an overview of the molecular complexes reported for the rapidly developing field of NH₃oxidation catalysis to form N₂. These systems exhibit several diverse structure types and innovative ligands to support transition metals capable of activating NH₃and mediating a challenging chemical transformation that requires breaking strong N−H bonds and forming an N−N bond en route to N₂formation. 

Abstract Within carnivore guilds, dominant competitors (e.g., lions,Panthera leo) are limited primarily by the density of prey, while subordinate competitors (e.g., African wild dogs,Lycaon pictus) have been limited by the density of dominant competitors. Historically, the fitness and population density of subordinate competitors have not been tightly linked to prey density. However, populations of large herbivores have declined substantially across sub‐Saharan Africa due to human impacts, and where prey depletion is severe, fitness costs for competitive subordinates may begin to outweigh the benefits of competitive release. Using long‐term intensive monitoring of African wild dogs in Zambia's Luangwa Valley Ecosystem (LVE), we tested the effects of prey depletion on survival and reproduction. We hypothesized that African wild dog fitness would be lower in prey‐depleted areas, despite lower lion densities. Our study area included four contiguous regions that varied in protection level, prey density, and lion density. We fit Bayesian Cormack–Jolly–Seber and closed‐capture models to estimate effects on survival and population density, and generalized linear models to estimate effects on reproductive success. We found that the LVE is a stronghold for African wild dogs, with an estimated median density of 4.0 individuals/100 km². Despite this high density, survival and reproduction differed among regions, and both components of fitness were substantially reduced in the region with the lowest prey density. Anthropogenic prey depletion is becoming an important limiting factor for African wild dogs. If prey depletion (or any other form of habitat degradation) becomes severe enough that its fitness costs outweigh the benefits of competitive release, such changes can fundamentally alter the balance between limiting factors for competitively subordinate species. 

Abstract Measurements of riverine dissolved inorganic carbon, total alkalinity (A_T), pH, and the partial pressure of carbon dioxide (pCO₂) can provide insights into the biogeochemical function of rivers, including the processes that control biological production, chemical speciation, and air‐water CO₂fluxes. The complexity created by these combined processes dictates that studies of inorganic carbon be made over broad spatial and temporal scales. Time‐series data like these are relatively rare, however, because sampling and measurements are labor intensive and, for some variables, good measurement quality is difficult to achieve (e.g., pH). In this study, spectrophotometric pH and A_Twere quantified with high precision and accuracy at biweekly to monthly intervals over a four‐year period (2018–2021) along 216 km of the Upper Clark Fork River (UCFR) in the northern Rocky Mountains, USA. We use these and other time‐series data to provide insights into the processes that control river inorganic carbon, with a focus onpCO₂and air‐water CO₂fluxes. We found that seasonal snowmelt runoff increasedpCO₂and that expected increase and decrease ofpCO₂due to seasonal heating and cooling were likely offset by an increase and loss of algal biomass, respectively. Overall, the UCFR was a small net source (0.08 ± 0.14 mol m⁻² d⁻¹) of CO₂to the atmosphere over the four‐year study period with highly variable annual averages (0.0–0.10 mol m⁻² d⁻¹). The seasonally correlated, offsetting mechanisms highlight the challenges in predictingpCO₂and air‐water CO₂fluxes in rivers.