Mercury concentrations, habitat and trophic position of Antimora rostrata and Macrourus holotrachys from South Georgia (Southern Ocean)

Mercury (Hg) is a neurotoxic element that can harm marine wildlife. Hg can reach the Southern Ocean through atmospheric and oceanic currents. However, data on Hg in Southern Ocean deep-sea fishes remain scarce. Our study assessed the influence of biological and ecological factors on Hg bioaccumulation in two deep-sea species, blue antimora (Antimora rostrata) and bigeye grenadier (Macrourus holotrachys), inhabiting the South Georgia region. Specifically, we aimed to: 1) analyse the habitat and trophic position of both species; 2) understand how Hg concentrations vary between tissues (muscle, brain, liver and gills); 3) evaluate how biological (length and weight) and ecological characteristics (trophic position (δ15N) and habitat (δ13C)) influence Hg concentrations. Muscle tissue had the highest Hg concentrations in both species, while the liver in A. rostrata and gills in M. holotrachys had the lowest. Overall, A. rostrata exhibited lower Hg concentrations (51.0 ± 9.0) than M. holotrachys (62.0 ± 11.0). No significant relationships were found between Hg concentrations and length, weight nor trophic position of A. rostrata. In contrast, M. holotrachys showed a positive relationship between Hg concentrations and habitat in all tissues, whereas for length and weight this positive relationship was observed in most tissues except the brain. A. rostrata is a pelagic feeder, whereas M. holotrachys mostly feeds near the sea bottom, highlighting how feeding strategy and habitat influence Hg bioaccumulation. It also reveals unexpected patterns of Hg distribution among tissues, particularly in the brain, where M. holotrachys exhibited one of the highest Hg concentrations

Sensory pollutants have negative but different effects on nestbox occupancy and breeding performance of a nocturnal raptor across Europe

Anthropogenic noise and artificial light at night (ALAN) are expanding globally, acting as pervasive sensory pollutants that can disrupt wildlife behaviour and reproduction. While most research has focused on diurnal species, the effects of these pollutants on the ecological response of nocturnal predators remain poorly understood. Using data from nine European countries, we investigated the effects of traffic noise, ALAN, and road proximity on nestbox occupancy and reproduction in the Tawny Owl (Strix aluco), a nocturnal raptor widespread across Europe. Traffic noise consistently reduced both nestbox occupancy and reproductive success regardless of road proximity. ALAN also impaired occupancy and reproduction, but its negative effect on reproduction changed based on the proximity to roads. Interestingly, the negative effect of ALAN was stronger in sites further from roads, but it attenuated in their proximity, where owls' hatching success and brood size moderately improved. This finding suggests that near roads, where prey abundance and availability are also generally high, owls may either find the prey regardless of ALAN or they may exploit it to facilitate hunting and brood provisioning. However, vicinity to roads might enhance mortality by vehicle collisions, which represents one of the greatest threats for the conservation of owls. Our findings highlight that anthropogenic noise and the co-occurrence between ALAN and roads can affect settlement decisions and breeding performance in nocturnal raptors, with potential consequences across the food chain. Mitigating anthropogenic noise and promoting nighttime-lighting systems that minimize owls' presence close to roads will represent valuable actions to improve their conservation

Unpouching Peracarida relationships with ultraconserved elements

Peracarida is a large group containing twelve orders of brooding crustaceans, including the large orders Amphipoda, Isopoda, Tanaidacea and Cumacea, and a series of smaller orders, some restricted to isolated habitats. The relationships of Peracarida have been disputed and little effo has been made to use extensive taxon sampling with a modern genetic approach. Here we present a novel probe set of ultraconserved elements (UCEs) developed for peracarids to investigate higher-level relationships using newly collected Antarctic material and collection-based specimens. Concatenated and coalescent-based analyses across different levels of occupancy matrices recovered strong support for the monophyly of Peracarida and for the clade Mancoida (Isopoda + Tanaidacea + Cumacea). Thermosbaenacea was consistently resolved as the sister group to all remaining peracarids. Within Amphipoda, our results contrast with previous phylogenies by placing Corophiida and Hyperiidea as early-branching lineages. In Isopoda, Oniscidea was recovered as monophyletic and concordant with morphological hypotheses. These findings provide one of the first phylogenomic frameworks for Peracarida and demonstrate the promise of UCEs for resolving long-standing questions in malacostracan evolution

Unlocking river biofilm microbial diversity: a comparative analysis of sequencing technologies

Freshwater ecosystems are under increasing pressure from pollution, habitat degradation and climate change, highlighting the need for reliable biomonitoring approaches to assess ecosystem health and identify the causes of biodiversity and ecosystem service loss. Characterisation of freshwater microbiomes has the potential to be an important tool for understanding freshwater ecology, ecosystem health and ecosystem function. High‐throughput sequencing technologies, such as Illumina short‐read and Pacific Biosciences long‐read sequencing, are widely used for microbial community analysis. However, the relative performance of these approaches for monitoring freshwater microbiomes has not been well explored. In this study, we compared the performance of long‐ and short‐read sequencing approaches to assess archaeal and bacterial diversity in 42 river biofilm samples across seven distinct river sites in England by targeting the 16S ribosomal RNA gene. Our findings demonstrated that longer reads generated by PacBio sequencing provide a higher taxonomic resolution, enabling the classification of taxa that remained unassigned in the short‐read Illumina datasets. This enhanced resolution is particularly beneficial for biodiversity assessments because it improves species‐level identification, which is crucial for ecological monitoring. Despite this, both sequencing methods produced comparable bacterial community structures regarding taxon relative abundance, suggesting that the sequencing approach does not profoundly affect the comparative assessment of community composition. However, while Illumina offers higher throughput and cost efficiency, PacBio's ability to resolve complex microbial communities highlights its potential for studies requiring precise taxonomic identification

Changes in chlorophyll-a in English rivers over the last 49 years

Ongoing anthropogenically-driven environmental change in rivers (e.g. increasing air temperature, changing river flow extremes, increases in some key nutrients and decreasing concentrations of other key nutrients) is expected to impact ecological status and the magnitude and frequency of river algal blooms. In this study we considered 49 years of data from up to 161 river sites across England using water-column chlorophyll-a as a measure of suspended algal biomass and used a Bayesian hierarchical model to explore the potential drivers of changing river chlorophyll-a concentrations. Over a period of five decades the changes in chlorophyll-a concentrations in rivers across England showed a mixed pattern in relationships with key environmental variables and are almost evenly divided between significant increases and decreases in those chlorophyll-a concentrations. Most river sites showed no significant change in the probability of algal bloom events (chlorophyll-a > 15 μg/l; > 30 μg/l or 45 μg/l) over the last 49 years. These results indicate that there has been no clear directional response in algal bloom events across England’s rivers to the changing pressures, including climate change and large-scale reductions in P concentrations achieved over the last 49 years from improved wastewater treatment. By identifying these differing patterns in chlorophyll-a trends and responses across England, this large-scale spatio-temporal analysis provides a basis for exploring the multiple pressures driving chlorophyll-a responses at local to regional scales

Metacommunity structural changes of Antarctic benthic invertebrates over the late Maastrichtian

Seymour (Marambio) Island, Antarctica has one of the most expanded onshore Cretaceous–Paleogene sedimentary successions in the world. The deposition of the López de Bertodano Formation (~70–65.6 Ma) covered a time of fluctuating sea temperatures, including cold snaps, and warming linked to Deccan Traps volcanism. Here, we study community dynamics of uppermost Cretaceous (Maastrichtian) Antarctic invertebrates using fossils from the Zinsmeister Collection, Paleontological Research Institution, USA, in order to assess ecological complexity prior to the Cretaceous–Paleogene (K–Pg) mass extinction. Our data set consists of 7400 fossils from 85 genera across bivalves, gastropods, cephalopods, echinoderms, brachiopods, scaphopods, polychaetes and octocorals, from 324 localities within six informal sub-units, KLBs 5–9. Due to positional uncertainty of the KLB boundaries, we performed sensitivity analyses to ensure robust results. We found that the number of significantly non-random taxonomic co-occurrences and complexity increased throughout this period. To investigate metacommunity structure that may arise from taxa interactions or environmental filtering, we used the Elements of Metacommunity Structure framework, where we found that taxa replacement, rather than nestedness, increased through time, also highlighting complexity. However, our sensitivity analyses found that our metacommunity results could not be distinguished from sampling biases in the most conservative sensitivity test. Thus, whilst we can be confident that ecological complexity increased throughout the Maastrichtian, the detailed community mechanisms behind this increase cannot be firmly established; nonetheless, this result reinforces the presence of a single, rather than two-fold, K–Pg extinction in the southern high latitudes

Airborne radiometric data: in search of the lost peatlands, Anglesey, North Wales

Soil carbon plays a crucial role in maintaining soil health, regulating water retention, and overall ecosystem function, while also acting as a carbon sink that can mitigate climate change. Updating peat information has become a priority in relation to carbon accounting. Soils attenuate radiometric flux by virtue of their bulk density and water saturation. The largest contrasts are associated with high carbon, wet peat zones. A revised attenuation theory demonstrates the response continuum of all soils and defines their response over the full range of saturation levels. The theory can be applied to any form of radiometric survey data. The relevance of the attenuation properties of airborne radiometric data to peat mapping is well established. Mainly due to survey height, the spatial resolution of the radiometric data is limited. It has been argued that conventional peat mapping has omitted many potential areas of peat, often excluded on the basis of depth. These smaller pockets of the carbon store have been termed the lost peatlands. A new observational and adaptable assessment of the peat extent across Wales has recently been published. An existing small airborne survey is used to provide an attenuation assessment of peat extents in relation to the control provided by the new map. Many of the peat zones are small (<0.05 km2) and are detected on only one or two flightlines. The large support volume (footprint) of airborne measurements provides a moving-average of subsurface contributions. Despite this, the attenuation response appears sufficient to either confirm or reject the evidence of a peat zone. The data also suggest many other areas of potential peat

Talking About the Weather: The Feasibility of Using Very High-Resolution Optical Satellite Imagery to Monitor Live and Stranded Cetaceans Around the UK and UK Overseas Territories

Monitoring live and stranded cetaceans can be expensive and logistically challenging, resulting in knowledge gaps. Very high-resolution (VHR) optical satellites are considered a potential solution to addressing some of these gaps. Despite success at detecting live and stranded cetaceans, satellites have only been trialed on restricted spatiotemporal scales. This project presents a framework for assessing the feasibility of using VHR optical satellite-based monitoring of cetaceans at high temporal frequency and local to global scales, focusing on the UK and UK Overseas Territories as a case study. We assess the primary environmental conditions necessary for the successful application of this technology: cloud cover and wind speed. Five-year monthly median “Total cloud cover” and “10m wind speed” ERA5 global reanalysis data were analyzed to map the spatial feasibility of satellite monitoring. We found that for the United Kingdom, VHR optical satellites could complement existing monitoring methods to achieve greater spatial and temporal coverage of live cetacean surveys, particularly, offshore, during the boreal spring and summer. However, satellites cannot address gaps in UK live cetacean monitoring in winter due to high wind speeds reducing whale detection probability. Based on environmental conditions, the tropics hold the greatest promise for achieving year-round satellite-based cetacean monitoring. In the Falkland Islands, particularly, the remote, unpopulated coastlines of West Island, satellites have the potential to improve strandings monitoring, opportunistically complementing existing stranding monitoring efforts

Quantifying nutrient loss across particle size fractions in eroded tropical soils using 239+240Pu fallout radionuclides

In sub-Saharan Africa, where livelihoods depend on agriculture, steep valley slope cultivation intensifies soil erosion, threatening agricultural sustainability by depleting fertile topsoil of nutrients. This study measured soil erosion and deposition using 239+240Pu fallout radionuclides and associated macro- and micronutrient loss across particle size fractions in the Oroba Valley, Nandi Hills, Kenya. Three experimental plots were assessed: Plot 1 (conventional tillage) and Plot 2 (terraced agricultural system), both of which were cleared for cultivation in 1940, while Plot 3 (historically shrubland) was recently cleared in 2023. A stratified sampling design was used to collect soil samples, which were analysed for particle size distribution, organic matter (OM) content, pH, and total elemental composition using ICP-MS/MS. The MODERN model to estimate erosion and deposition rates using 239+240Pu inventories integrates nutrient losses across specific particle sizes to estimate the nutrients lost. There was severe soil erosion in Plots 1 and 2, with net losses of 13.68 t ha-¹ yr⁻¹ and 6.09 t ha-¹ yr⁻¹ , respectively, while Plot 3 showed minimal loss (0.32 t ha-¹ yr⁻¹), reflecting the protective effect of vegetative cover. Fine particles (100 µm) retained K and Mg. This study shows how 239+240Pu isotopes can be used as sensitive indicators of soil loss and fertility degradation, offering land management and conservation insights

Age of granitoid magmatism in South Georgia and correlations to southern Patagonia and the northern Antarctic Peninsula

South Georgia forms one of the most isolated fragments of continental crust on Earth and lies in a remote location in the Southern Ocean. Its geology is dominated by Early Cretaceous back-arc turbidite successions that are in faulted contact with a late Palaeozoic – early Mesozoic accretionary complex. The accretionary complex includes fragments of a deformed accretionary prism and ophiolite that are intruded by a suite of granitoid plutons that are dated here. Granitoid magmatism has been identified from the Middle Jurassic (c. 163 Ma) and Late Cretaceous (c. 107 Ma, c. 86 Ma), which can be correlated with convergent margin magmatism from the southern (Fuegian) Andes and Cordillera Darwin of southern Patagonia, and the northern Antarctic Peninsula, with the Late Cretaceous magmatism restricted to the western parts of each area. These correlations support earlier findings that established a contiguous relationship between the southeast sector of South Georgia and southernmost Patagonia (south of the Magallanes fault zone) and the northern sector of Graham Land (Antarctic Peninsula)