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A European monsoon-like climate in a warmhouse world
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The middle Eocene warmhouse period (45 million years ago) featured atmospheric carbon dioxide concentrations equivalent to those projected under high future emission scenarios. Seasonal- to weather timescale climate reconstructions from this period can provide critical insight into the impact of Anthropogenic warming on intra-annual variability in temperature and precipitation. Here, we combine daily-scale reconstructions of the evolution of temperature and the water cycle in western Europe based on stable oxygen and clumped isotope analyses on the fastest-growing gastropod known in the fossil record: Campanile giganteum. Our dataset shows that the middle Eocene of western Europe featured monsoon-like conditions, with seawater temperatures of ˊ24 °C during mild and wet winters, 30 °C during hot and dry spring and autumn seasons, and ˊ28 °C during warm and comparatively wet summers. Coupled climate model simulations using the Community Earth System Model indicate these seasonal variations in temperature and precipitation were driven by shifting atmospheric and oceanic circulation regimes over Western Europe, with winds from different directions bringing distinct waters to the region and minimal wind during spring reducing cooling through diminished latent heat flux. Our results highlight that Europe may experience wetter summers with more frequent extreme rainfall events under future high emissions scenarios.
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RBINS Staff Publications 2025 OA
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Clumped isotope thermometry (Δ47) measurements in marine gastropods suggest equilibrium precipitation
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The clumped isotope paleothermometer (Δ47) has been used to reconstruct temperatures from various biogenic carbonate archives. Calibration studies demonstrate that some biogenic carbonates precipitate in Δ47 equilibrium and record growth temperatures accurately (e.g., many bivalve mollusks), while others appear to exhibit disequilibrium, or ‘vital’, effects and yield isotopically reconstructed temperatures that are biased (e.g., shallow-water corals). These studies have largely excluded marine gastropods, so it is not known whether they tend to precipitate their shells in or out of isotopic equilibrium. In this study, we present seasonal-scale δ18O and seasonally targeted Δ47 and Δ48 measurements from modern marine gastropods representing 8 genera and 10 species, reconstructing apparent growth temperatures and screening for equilibrium precipitation. We find that most marine gastropods appear to precipitate in Δ47 and Δ48 equilibrium and faithfully record environmental temperatures, making them suitable for Δ47-paleothermometry. A few gastropods (Caviturritella/Turritella sp., Campanile symbolicum, Megastraea undosa) appear to precipitate out of Δ47 equilibrium, though these disequilibrium signatures may partially be explained by differences between actual growth temperatures and instrumental calibration temperatures (Caviturritella/Turritella sp., M. undosa) or differences between inner and outer layer precipitation (C. symbolicum). We present new Δ47-temperature data for 2 Middle Eocene Campanile giganteum fossils collected from the Paris Basin and discuss how to interpret the results in the context of our modern samples. Finally, in conducting this calibration we demonstrate paired Δ47/Δ48 as an effective tool to screen for disequilibrium precipitation in marine gastropods.
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RBINS Staff Publications 2025 OA
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Endocranial anatomy and phylogenetic position of the crocodylian Eosuchus lerichei from the late Paleocene of northwestern Europe and potential adaptations for transoceanic dispersal in gavialoids
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Eosuchus lerichei is a gavialoid crocodylian from late Paleocene marine deposits of northwestern Europe, known from a skull and lower jaws, as well as postcrania. Its sister taxon relationship with the approximately contemporaneous species Eosuchus minor from the east coast of the USA has been explained through transoceanic dispersal, indicating a capability for salt excretion that is absent in extant gavialoids. However, there is currently no anatomical evidence to support marine adaptation in extinct gavialoids. Furthermore, the placement of Eosuchus within Gavialoidea is labile, with some analyses supporting affinities with the Late Cretaceous to early Paleogene “thoracosaurs.” Here we present novel data on the internal and external anatomy of the skull of E. lerichei that enables a revised diagnosis, with 6 autapormorphies identified for the genus and 10 features that enable differentiation of the species from Eosuchus minor. Our phylogenetic analyses recover Eosuchus as an early diverging gavialid gavialoid that is not part of the “thoracosaur” group. In addition to thickened semi-circular canal walls of the endosseous labyrinth and paratympanic sinus reduction, we identify potential osteological correlates for salt glands in the internal surface of the prefrontal and lacrimal bones of E. lerichei. These salt glands potentially provide anatomical evidence for the capability of transoceanic dispersal within Eosuchus, and we also identify them in the Late Cretaceous “thoracosaur” Portugalosuchus. Given that the earliest diverging and stratigraphically oldest gavialoids either have evidence for a nasal salt gland and/or have been recovered from marine deposits, this suggests the capacity for salt excretion might be ancestral for Gavialoidea. Mapping osteological and geological evidence for marine adaptation onto a phylogeny indicates that there was probably more than one independent loss/reduction in the capacity for salt excretion in gavialoids.
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RBINS Staff Publications 2025
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De karakteristieken en geografisch/historische verspreiding van veldsteen
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RBINS Staff Publications 2025
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Assessing Histotaphonomy: A Pilot Study Using Image Analysis for Quantitative Scoring of Bone Diagenesis
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ABSTRACT This pilot study focusses on improving the methodological approach of histotaphonomy by integrating image analysis software for assessing bone diagenesis in both bone histological sections and microcomputed tomography (μ-CT) scans of the same bone slice. Femurs and ribs from six individuals buried at the churchyard of St. Anne in Koekelberg (Belgium, 1833–1916) were analyzed with μ-CT and histology (light microscopy and scanning electron microscopy). Bone diagenesis was scored visually by the assessor, as well as quantitatively by image analysis. The results suggest that image analysis is an effective quantitative scoring method, eliminating subjectivity bias, specifically regarding the precision in percentage calculation of preserved areas which aids in assigning the right category of the Oxford Histological Index. However, algorithm limitations can affect the accuracy and reliability of the results, hence specialized expertise is advised. The taphonomic results show that bacterial degradation was similar within and between rib and femur of the same individual but varied between individuals depending on burial treatment (wooden versus zinc-lined coffins). Other inter-skeletal differences were caused by biological parameters such as the amount of primary lamellar bone. This study demonstrates the accuracy of quantitative scoring by advancements in technology such as image analysis, creating a basis for the incorporation of machine learning algorithms in future histotaphonomy studies. It also stresses the importance of using both histology and μ-CT as complementary methods.
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RBINS Staff Publications 2025
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Late Pleistocene modern human diversity in Central Africa
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RBINS Staff Publications 2017
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The Upper Paleolithic human remains from the Troisieme caverne of Goyet (Belgium)
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RBINS Staff Publications 2017
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The transition between coastal and offshore areas in the North Sea unraveled by suspended particle composition
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Identifying the mechanisms that contribute to the variability of suspended particulate matter concentrations in coastal areas is important but difficult, especially due to the complexity of physical and biogeochemical interactions involved. Our study addresses this complexity and investigates changes in the horizontal spread and composition of particles, focusing on cross-coastal gradients in the southern North Sea and the English Channel. A semi-empirical model is applied on in situ data of SPM and its organic fraction to resolve the relationship between organic and inorganic suspended particles. The derived equations are applied onto remote sensing products of SPM concentration, which provide monthly synoptic maps of particulate organic matter concentrations (here, particulate organic nitrogen) at the surface together with their labile and less reactive fractions. Comparing these fractions of particulate organic matter reveals their characteristic features along the coastal-offshore gradient, with an area of increased settling rate for particles generally observed between 5 and 30 km from the coast. We identify this area as the transition zone between coastal and offshore waters with respect to particle dynamics. Presumably, in that area, the turbulence range and particle composition favor particle settling, while hydrodynamic processes tend to transport particles of the seabed back towards the coast. Bathymetry plays an important role in controlling the range of turbulent dissipation energy values in the water column, and we observe that the transition zone in the southern North Sea is generally confined to water depths below 20 m. Seasonal variations in suspended particle dynamics are linked to biological processes enhancing particle flocculation, which do not affect the location of the transition zone. We identify the criteria that allow a transition zone and discuss the cases where it is not observed in the domain. The impact of these particle dynamics on coastal carbon storage and export is discussed.
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RBINS Staff Publications 2024 OA
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Lessons from the calibration and sensitivity analysis of a fish larval transport model
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ABSTRACT: Numerous fish populations show strong year-to-year variations in recruitment. The early life stages play a crucial role in determining recruitment and dispersal patterns. A helpful tool to understand recruitment and dispersal involves simulations with a Lagrangian transport model, which results from the coupling between a hydrodynamic model and an individual-based model. Larval transport models require sound knowledge of the biological processes governing larval dispersal, and they may be highly sensitive to the parameters selected. Various assumptions about larval traits, behaviour and other model parameters can be tested by comparing simulation results with field data to identify the most sensitive parameters and to improve model calibration. This study shows that biological parameterization is more important than inter-annual variability in explaining the year-to-year differences in larval recruitment of common sole in the North Sea and the eastern English Channel. In contrast, year-to-year variability of connectivity leads to higher variability than changes in the biological parameters. The most influential parameters are pelagic larval duration, spawning period and mortality. Calibration over a 12 yr recruitment survey shows that a scenario with low mortality associated with a long larval duration and behaviour involving nycthemeral and tidal migration best reproduces the observations. This research provides insights into factors influencing fish dispersal and recruitment, suggesting a strategy for enhancing the accuracy of models in upcoming studies. The study supports the improvement of larval dispersal modelling by incorporating an easily applicable sensitivity analysis for both calibration and validation. Incorporating sensitivity analyses enhances larval dispersal models, providing performing tools that can contribute to informed fisheries management and understanding of recruitment variability.
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RBINS Staff Publications 2024
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Discovery-defense strategy as a mechanism of social foraging of ants in tropical rainforest canopies
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RBINS Staff Publications 2017
