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A circumpolar review of the breeding distribution and habitat use of the snow petrel (Pagodroma nivea), the world’s most southerly breeding vertebrate
Get PDFKnowledge of the spatial distribution of many polar seabird species is incomplete due to the remoteness of their breeding locations. Here, we compiled a new database of published and unpublished records of all known snow petrel Pagodroma nivea breeding sites. We quantified local environmental conditions at sites by appending indices of climate and substrate, and regional-scale conditions by appending 30 year mean (1992–2021) sea-ice conditions within accessible foraging areas. Breeding snow petrels are reported at 456 sites across Antarctica and subantarctic islands. Although many counts are old or have large margins of error, population estimates available for 222 known sites totalled a minimum of ~ 77400 breeding pairs. However with so many missing data, the true breeding population will be much higher. Most sites are close to the coast (median = 1.15 km) and research stations (median = 26 km). Median distance to the November sea-ice edge (breeding season sea-ice maximum) is 430 km. Locally, most nests occur in cavities in high-grade metamorphic rocks. Minimum air temperatures occur at inland sites, and maxima at their northern breeding limit. Breeding location and cavity selection is likely determined by availability of suitable breeding substrate within sustainable distance of suitable foraging habitat. Within this range, nest sites may then be selected based on local conditions such as cavity size and aspect. Our database will allow formal analyses of habitat selection and provides a baseline against which to monitor future snow petrel distribution changes in response to climate change
Medals awarded to the personnel of the Scottish National Antarctic Expedition, 1902–1904: an inconsistency of recognition
Get PDFThe 1902–1904 Scottish National Antarctic (Scotia) Expedition led by William Speirs Bruce was overshadowed by the 1901–1904 British National Antarctic (Discovery) Expedition led by Robert Falcon Scott. The establishment of the independent Scottish expedition had been resented by those promoting the ‘official’ British venture and the accolades accorded to each on their return home were very different. The Royal Scottish Geographical Society honoured both leaders with prestigious medals and later, after public pressure, rewarded Scotia’s captain and scientific staff but not her officers or crew. By contrast, the Royal Geographical Society rewarded the leader and personnel of the Discovery expedition and completely ignored Scotia. An even greater demarcation arose when the Polar Medal was hastily created for the benefit of Scott and the Discovery team, and subsequently extended to the crews of their two relief ships. Aggrieved that his men had not received such public recognition, Bruce commissioned his own expedition silver medal, yet did not present it to all eligible personnel. His exclusion of artist William Cuthbertson and taxidermist Alastair Ross is paradoxical given his indignation over the partiality of other awards but may indicate some unacknowledged personal friction during the Scotia expedition. The paper illuminates the politics and personalities involved in recognition of the achievements of early twentieth-century Antarctic exploration after the events themselves
Iodine Speciation in Snow during the MOSAiC Expedition and its Implications for Arctic Iodine Emissions
Get PDFPhotochemical release of iodine from snow has been suggested as a source of reactive iodine to the Arctic atmosphere, however understanding of the underlying mechanism and potential source strength is hindered by a lack of measurements of iodine concentration and speciation in snow. Moreover, the origin of snow iodine is also unknown. Here, we report iodine speciation measurements in Arctic snow on sea ice at a range of snow depths from 177 samples, representing 80 sampling events, from December 2019 to October 2020 collected during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. We demonstrate that while there appears to be a source of iodine, in particular iodate, to the base of the snow over first year ice, this does not influence iodine concentration in the surface snow. There is instead evidence of a top-down source of iodine, potentially from iodine-enriched marine aerosol, as well as some evidence for episodic influx of iodate with dust. The potential for photochemical release of molecular iodine (I2) from iodide in surface snow was investigated, and it was demonstrated that this could provide an iodine emission flux to the Arctic atmosphere comparable to oceanic fluxes. Knowledge of the prevalence and speciation of iodine in Arctic snow will contribute to better understanding of its contribution to observed concentrations of polar iodine oxide (IO), and hence its contribution to the depletion of tropospheric ozone in the Arctic
A High‐Resolution Microscopy System for Biological Studies of Cold‐Adapted Species Under Physiological Conditions
Get PDFThe Antarctic seabed harbors significant biodiversity, and almost 90% of oceanic environments are permanently below 5 °C (i.e., deep sea and polar regions). However, organisms whose entire lifecycle occurs around 0 °C are understudied, leaving this large and diverse proportion of the global biome poorly understood. To address this question at the cellular level, tools are required for high‐resolution imaging of biological systems under physiological conditions. This poses severe technical challenges. High‐resolution imaging objectives require short working distances and immersion media, causing rapid heat transfer from the microscope to the sample. This affects the viability of live specimens and the interpretability of results. Here, we present a method for high‐fidelity imaging of live biological samples at temperatures of around, or below, 0 °C. It relies on hardware additions to traditional microscopy, namely as a cooling collar, 10% ethanol as an immersion medium, and nitrogen flow to reduce condensation It can be straightforwardly implemented on different microscopy modalities, including super‐resolution imaging. The method is demonstrated in live cell cultures derived from Antarctic fish and highlights the need to maintain physiological conditions for these fragile samples. Future applications include evolutionary biology, biophysics and biotechnology
Response of South Asia PM2.5 pollution to ammonia emission changes and associated impacts on human health
Get PDFCountries in South Asia are suffering severe PM2.5 pollution with rapid economic development, impacting human health and the environment. Whilst much attention has been given to understanding the contribution of primary emissions, the contribution of agriculture to PM2.5 concentrations, especially from agricultural ammonia (NH3) emissions, remains less explored. Using an advanced regional atmospheric chemistry and transport modelling system (WRF-EMEP) with a new estimate of anthropogenic NH3 emissions inputs, we estimate the influence of agricultural NH3 emissions on surface PM2.5 in South Asia and evaluate the health impacts and the economic losses attributable to PM2.5 in 2018. Results show that WRF-EMEP can reproduce magnitudes and variations of PM2.5 well, with a high annual mean PM2.5 concentration that exceeds 120 µg/m2 and mainly appeared in the Indo-Gangetic Plain. We estimate 2,228,000 (95 % Confidence Interval: 2,052,000–2,400,000) premature deaths and US 66,000 (61,000–71,000) million economic losses through this pathway can be attributed to NH3 emissions. These findings confirm that in the current NH3-rich chemical environment of South Asia, the efficiency of PM2.5 reduction is only moderately sensitive to the reduction in intensity of NH3 emissions until emissions are cut very severely. Thus, SO2, NOx and NH3 emissions controls need to be considered jointly for greater mitigation of ambient secondary PM2.5 in South Asia
Volatile odours reflect breeding status but not social group membership in captive Damaraland mole-rats
Get PDFIn mammals, olfaction plays a key role in social behaviour, for example, in identifying mating opportunities and potential rivals. However, we still have a limited understanding of how social information is encoded in animal odours, including the social determinants of chemical similarity and diversity. Here, we used gas chromatography to analyse the chemical composition of swabs taken from the facial and anogenital regions of Damaraland mole-rats, Fukomys damarensis, a highly social subterranean mammal that relies almost exclusively on olfactory and tactile social cues. We found no sign of individual identity across the two body areas sampled; samples from the facial region and samples of the anogenital region from the same individual were not similar to each other, suggesting that these regions carry different information. However, chemical profiles varied significantly by sex and breeding status; female breeders differed from nonbreeders in their anogenital profiles and had higher chemical diversity in their facial profiles compared with both males and nonbreeders. Interestingly, we found no signals of social group identity. Instead, individual identity may be conveyed through signature mixes that are learned through frequent contact, rather than through specific odours associated with genetic kinship or social group membership. Our results highlight the complexity of chemical communication systems in social species and suggest that signals of group level identity are not necessary for behavioural responses based on group membership
Environmental degradation and loss of polyester marker flags are major sources of localized plastic pollution in the Antarctic
Get PDFReducing plastic pollution of the Antarctic environment is a priority for the Antarctic Treaty Consultative Meeting (ATCM) and Council of Managers of National Antarctic Programs (COMNAP). Polyester flags mounted on bamboo poles are commonly used by governmental and tourism operators as markers of safe travel routes, scientific equipment and depots in snow-covered areas. Polar environmental conditions can rapidly degrade polyester flags, resulting in plastic release into the environment. This study aimed to quantify the degree of polyester flag degradation and investigate alternative, less polluting flag types. Pre-weighed flags of four types - standard polyester, hemmed polyester, organic cotton canvas and Ventile (a tight-weave cotton fabric) - were deployed close to Rothera Research Station, Antarctic Peninsula, from February 2023 to January 2024, after which any changes in weight were recorded. On average, each standard polyester flag lost 25.5% (± standard error (SE) 0.8) of its weight, equating to the release of 8.3 g of plastic into the environment; however, hemming the flag reduced this loss to 13.3% (± SE 3.7). Ventile was almost as durable as unhemmed polyester (loss of 26.9% (± SE 3.8)), whereas cotton canvas was the least durable (loss of 44.1% (± SE 4.3)). Switching from standard polyester to Ventile flags would prevent the annual release of > 8.3 kg of plastic into the environment around Rothera Research Station, and potentially ~300 kg across all Antarctic operator activities. This is a conservative estimate compared to a potential additional 800 kg of plastic that could be lost to the environment due a high proportion of deployed flags not being recovered. Further investigations to identify cost-effective sustainable flag materials are recommended to comply with ATCM and COMNAP recommendations concerning plastic management in Antarctica
Wet-bulb temperature extremes locally amplified by wet soils
Get PDFWet-bulb temperature extremes (WTEs) occur due to a combination of high humidity and temperature, and are hazardous to human health. Alongside favourable large-scale conditions, surface fluxes play an important role in WTEs; yet, little is known about how land surface heterogeneity influences them. Using a 10-year, pan-African convection-permitting model simulation, we find that most WTEs have spatial extents less than 2,000 km2. They occur preferentially over positive soil moisture anomalies (SMA) typically following rainfall. The wet-bulb temperature is locally amplified by 0.5–0.6 degrees C in events associated with smaller-scale SMA (50 km across) compared to events with larger-scale SMA (300 km across). A mesoscale cifrculation, resulting from stronger spatial contrasts of sensible heat flux, more efficiently concentrates moist, warm air in a shallower boundary layer. This mechanism could explain the underestimation of peak Twb values in coarser-resolution products. The role of antecedent SMA from recent rainfall may help issue localized early warnings
Heat limits scale with metabolism in ectothermic animals
Get PDF1. Ectotherms given time to acclimate to warmer environments, habitats or experimental treatments tend to tolerate higher maximum temperatures, but only slightly higher. This means warmer acclimated organisms live closer to their physiological temperature limits (their 'critical temperatures'). The reason for this modest—and often highly variable—plasticity of heat limits is debated but raises concerns for resilience to future climate warming.
2. Experiments have shown heat tolerance is dependent not just on the magnitude of thermal stress but also on time via exposure duration. This implicates rate processes in the regulation of heat limits, yet few studies have explored this possibility. Invoking biological rates (such as metabolic rate) to explain the plasticity of critical temperatures is complicated by the need to account for temperature, time and the nonlinear dependence of rates on temperature.
3. We developed a new approach to explore whether incorporating estimated metabolic rate and its thermal scaling could explain the apparently modest and highly variable capacities of ectotherms to adjust their heat limits. To do this, we re-evaluate a large thermal tolerance dataset for diverse ectothermic animals heated from different acclimation temperatures up to their critical temperature. By integrating temperature, time and the exponential relationship between temperature and metabolic rate, we compute a cumulative ‘metabolic currency’ that ectotherms expend (or accumulate) before reaching their heat limits. We then explore how this quantity varies for ectotherms acclimated to different temperatures.
4. Our ‘metabolic rescaling’ has a dramatic impact on explaining variation in heat limits, revealing that heating tolerance is effectively fixed within a species such that heat limits from any acclimation temperature can be predicted with remarkable accuracy by measuring heat limits at any other acclimation temperature. Heating rate also has a strong, consistent, influence.
5. Evidently, warmer-acclimated organisms only marginally elevate their critical temperatures because they have a fixed amount of energy to spend during heating, and they spend it at a faster rate in warmer temperatures. This provides a very different perspective to leading explanations that organismal heat limits are constrained by hard physiological boundaries and instead encourages unification of thermal tolerance and metabolic scaling theory
The genome sequence of the shaded broad-bar moth, Scotopteryx chenopodiata (Linnaeus, 1758)
Get PDFWe present a genome assembly from a male specimen of Scotopteryx chenopodiata (Shaded Broad-bar; Arthropoda; Insecta; Lepidoptera; Geometridae). The genome sequence has a total length of 337.86 megabases. Most of the assembly (98.85%) is scaffolded into 31 chromosomal pseudomolecules, including the Z sex chromosome. The mitochondrial genome has also been assembled, with a length of 16.65 kilobases
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