HAL Université des Antilles
Not a member yet
25497 research outputs found
Sort by
Scleractinian Coral Skeletons as Natural Archives of Global Change: A Cross-Disciplinary Investigation
No full textInternational audienceScleractinian coral skeletons serve as valuable environmental archives, offering key insights into past climate and ocean variability. Understanding the mechanisms underlying coral calcification is essential for reconstructing accurate paleoenvironmental records. However, calcification is a complex process regulated by both biological and environmental factors. This study explores the interplay between coral skeletal geochemistry and physiological processes, focusing on species-specific growth patterns, biomineralization dynamics, and the impact of diagenesis. We highlight the use of elemental ratios (e.g., Mg/Ca, Sr/Ca, Li/Mg) as proxies for environmental reconstructions while addressing biases introduced by skeletal heterogeneity, bioerosion, and secondary mineral precipitation. Additionally, we discuss how physiological traits, such as symbiosis, nutrient uptake, and respiration, influence calcification and may affect the preservation of geochemical archives over time. The integration of high-resolution geochemical analyses with biological insights is of great importance for refining paleoenvironmental proxies and enhancing the accuracy of climate reconstructions. This multidisciplinary approach provides a broader perspective on coral biomineralization, a critical issue for assessing reef resilience in a changing ocean
Des Savoirs Locaux à la Simulation : une Approche Intégrée pour anticiper les Impacts Climatiques sur les Tubercules du Pacifique
No full textInternational audienc
Geochronology and geochemistry of Cenozoic magmatism in the north-western Ecuadorian Andes: the role of crustal thickness
No full textInternational audienceThe Ecuadorian Cenozoic arc developed over autochthonous continental and accreted oceanic terrains. We reconstruct the tectono-magmatic evolution of the northernmost part of this arc using a comprehensive, multiproxy approach that incorporates whole-rock chemistry and zircon petrochronology, including U-Pb geochronology, trace element geochemistry, and Hf-O isotopic analysis. Our results reveal two distinct magmatic periods at 41-16 Ma and 14-7 Ma. The older period is characterized by tonalitic rocks that exhibit trace element ratios, δ 18 O values (6.4-3 ‰), and εHf values (+17 -+12) in zircons that are indicative of highly juvenile sources, while the younger period comprises granodioritic rocks derived from a more enriched reservoir (δ 18 O: 8.2-5.8 ‰ and εHf: +13 -+7). The older magmas formed within the amphibole stability field in a moderately thick crust (~ 35 km), while the younger magmas were generated within the garnet stability field in thickened crust (~60 km). The transition from intermediate crustal thickness and juvenile settings to a thicker crust and more enriched settings occurred at around 14 Ma. This shift was most likely related to the arrival of the young (and buoyant) Nazca plate at the South American margin, which would have resulted in the shallowing of the subduction angle, increased compressional stresses, and facilitated melting of an evolved oceanic crust. This study highlights the utility of zircon petrochronology in unraveling the crustal-scale evolution of Cordilleran arcs, providing valuable insights into the dynamic processes that control continental growth and orogen
Image-based ecological assessment of deep-sea sponge, coral and other cnidarian assemblages through a morpho-functional approach
No full textPorifera and Cnidaria are key phyla of marine ecosystem functioning. Slow-growing and long-lived, they show limited resilience to human disturbances and are therefore commonly used as indicator taxa of Vulnerable Marine Ecosystems. Their diversity and distribution largely rely on seafloor images, but image-based identification (ID) of sponges and cnidarians beyond class/order ranks is hindered by morphological plasticity and convergence, and the need of microscopic diagnostic characters or molecular markers that are not accessible on images. Higher-rank taxonomy also poorly reflects their morphological and functional diversity. To address this issue, we applied an image-based classification relying on multiple macro-morphological traits to define statistically morpho-functional groups (MFGs) based on these traits, then used as response variables in ecological analyses, instead of taxa. We applied this framework to seamounts and island slopes in the Mozambique Channel, a poorly sampled region where taxonomic limitations are acute. We aimed to evaluate the relevance of a sponge/cnidarian morpho-functional approach to characterise their diversity and distribution at multiscales, responses to environmental gradients and structuring roles on the megabenthic community. We identified 37 sponge and 34 cnidarian MFGs with varying distributions among sites. MFGs richness and beta diversity varied among seamounts, and between seamounts and island slopes. Hydrology explained 26% of the sponge MFG spatial structure at the channel scale, while topography and substrate played a main role at a smaller scale in the northern part of the channel (17-23%). Some sponge/cnidarian MFGs co-structured with other megabenthic taxa (e.g., sea urchins, comatulids, ophiuroids). This morpho-functional approach, especially effective for sponges, allowed quantifying morphological variation of habitat-forming taxa using qualitative traits, identifying environmental drivers shaping the spatial distribution of these traits, and characterising potential biogenic habitats they provide for other megabenthic organisms. The framework proposes metrics to detect and quantify the heterogeneity and spatial variability of potentially vulnerable biogenic habitats in imagery-based studies
Expanding invasive species impact assessments to the ecosystem level with EEICAT
No full textPLoS Biology. In Press.The ecological impacts of biological invasions vary widely in type, scale, and severity, highlighting the need for consistent assessment tools. The Environmental Impact Classification for Alien Taxa (EICAT) provides a standardized framework for assessing their effects, but focuses mainly on population-level impacts. We introduce the Extended Environmental Impact Classification for Alien Taxa (EEICAT), which incorporates impacts across three ecological dimensions from individuals to ecosystems. EEICAT enables classification of 19 impact types at the invasion-event level, making it suitable for primary research, synthesis, and management. This framework improves the detection, comparison, and communication of complex ecological impacts caused by biological invasions.</div
Inclusion des minorités dans les principales études sur le cancer de la prostate métastatique : une revue exploratoire centrée sur les Afro-descendants
No full textBackground: Prostate cancer incidence and metastatic progression appear higher in men of African descent globally. This raises the question of whether Afro-descendant populations are adequately represented in major phase III clinical trials influencing metastatic prostate cancer treatment. Objective: To assess the inclusion of Afro-descendant populations in major studies. Methods: We conducted a scoping review using the MEDLINE database. We included English-language, phase III randomized clinical trials from 2005 to 2024 evaluating systemic drug therapies for metastatic prostate cancer. Trials were selected based on their impact on clinical guidelines or drug approvals. Supplementary data were reviewed to complete missing information. Results: Among 1,295 studies screened as of September 1st, 2024, 29 met inclusion criteria, totaling 26,600 participants. Of these, 17 reported ethnic data. Afro-descendant individuals made up 3.33% of the population in those studies. Six trials were stratified by ethnicity: three analyzed Afro-descendants specifically, while the others grouped them under “Others.” None reported significant outcomes for the Afro-descendant group regarding the primary endpoint. Conclusion: Afro-descendant populations are underrepresented in pivotal trials for metastatic prostate cancer. Improved recruitment policies are needed to ensure better representation and more generalizable treatment outcomes.Introduction : L’incidence du cancer de la prostate semble plus élevée chez les hommes d’ascendance africaine à travers le monde. Ces derniers semblent être plus susceptibles de développer des formes métastatiques, pouvant mener au décès. La question de l’inclusion des hommes afro-descendants dans les principales études de phase III ayant influencé la prise en charge du cancer de la prostate métastatique se pose. Méthodes : Dans cette revue exploratoire, nous avons identifié des études via la base de données électronique MEDLINE. Nous avons inclus des essais cliniques randomisés de phase III rédigés en anglais, publiés entre 2005 et 2024, portant sur un traitement médicamenteux du cancer de la prostate métastatique. Les études ayant permis une modification des recommandations et ayant abouti à une autorisation de mise sur le marché de médicaments ont été incluses. Résultats : Sur les 1 295 études examinées, 29 ont été retenues, impliquant 26 600 patients. Parmi elles, 17 comportaient des données ethniques. Les afro-descendants ne représentaient que 3,33% de la population parmi les études disposant de données ethniques. Six de ces études incluaient une stratification ethnique, parmi lesquelles seulement trois prenaient en compte les personnes afro-descendantes. Aucune de ces études n’a montré de résultats significatifs dans la population afro-descendante concernant le critère de jugement principal. Conclusion : Il existe une sous-représentation de la population afro-descendante dans les études majeures ayant modifié la prise en charge du cancer de la prostate métastatique. Des recherches supplémentaires sont nécessaires pour explorer les multiples hypothèses concernant les causes de cette disparité. Par ailleurs, nos résultats soulignent la nécessité d’améliorer les politiques de recrutement afin d’assurer une meilleure représentation des populations afro-descendantes et des résultats plus généralisables à l’échelle mondiale
When Pacific children sketch the sea and their fishing practices : involving children in marine social science research
No full textThe 'SOCPacific' project (A Sea of Connections: Contextualising Fisheries in the South Pacific Region, 2018-2022,funded by ANR-DFG) sought to investigate the 'sea ofconnections' in which fishing practices and fisheriesmanagement are embedded across the South Pacific.Engaging children was crucial for adopting a marine sustainability framework that recognises intergenerationaljustice concerns and upholds children's rights. Childrenin the region are active participants in fishing activitiesand play a key role in sustaining the connections amongpeople, the ocean, and marine life. Just like adults, theytoo can exercise their rights and responsibilities towardthe ocean. Art workshops allowed them to take part in co-building our research agenda
État des lieux de la prise en charge des accidents d’exposition sexuelle dans le CeGIDD du CHU de Guadeloupe : bilan d'une réorganisation du parcours de soin
No full textThis study evaluates the impact of the reorganization of the care pathway for sexual exposure accidents (SEA) in Guadeloupe, which occurred in July 2021 with the transfer of care from the infectious disease service to the sexual health center. The goal of this reorganization was to improve access to post-exposure prophylaxis (PEP) and strengthen sexual health prevention. The results demonstrate an increase in consultations for SEA, mainly spontaneous consultations. However, the median delay in initiating PEP increased, with a decrease in early initiations. Challenges persist, notably insufficient referral from the emergency department and limited post-exposure follow-up. The study also reveals a shift in the patient profile, with an increase in the proportion of women and a decrease in men who have sex with men, while the migrant population remains a minority. These findings emphasize the need for improved awareness among healthcare professionals and key populations to optimize the management of SEA.Cette étude évalue l'impact de la réorganisation du parcours de soins des accidents d'exposition sexuelle (AEVsex) en Guadeloupe, survenue en juillet 2021 avec le transfert de la prise en charge du Service de Maladies Infectieuses et Tropicales vers le Centre Gratuit d’Information de Dépistage et de Diagnostique. Cette réorganisation visait à améliorer l'accès au traitement post-exposition et à renforcer la prévention en santé sexuelle. Les résultats montrent une augmentation des consultations pour AEVsex, principalement spontanées. Cependant, le délai médian d'initiation du TPE a augmenté, avec une baisse des prises en charge précoces. Des défis demeurent, notamment une orientation insuffisante depuis les urgences et un suivi post-exposition limité. L'étude révèle aussi une évolution du profil des personnes exposées, avec une augmentation de la proportion de femmes et une diminution des hommes ayant des rapports sexuels avec des hommes, tandis que la population migrante reste minoritaire. Ces résultats soulignent la nécessité d'une meilleure information des professionnels de santé et des populations clés pour optimiser la prise en charge des AEVsex
Modeling spatio-temporal dynamics of Patagonian toothfish spawning in Kerguelen waters using CPUE data
No full textInternational audienceThe act of spawning of fish can be influenced by a variety of factors, including environmental conditions and human activities, particularly fishing. Patagonian toothfish (Dissostichus eleginoides) is a commercially exploited fish species, occupying the southern Patagonian and Chilean shelves, as well as the sub-Antarctic submarine plateaux. It is characterized by a late maturity and slow body growth, which are key considerations in its management and conservation. In this study, we investigated the spatio-temporal dynamics of Patagonian toothfish spawners in the Kerguelen region using fishery observer data, from 2020 to 2024. We predicted spawner hotspots and seasonal trends of spawner abundance using spatially-explicit Generalized Additive Models (GAMs) that modeled the spawner CPUE (Catch Per Unit of Effort). Our results suggest that toothfish female spawners aggregate at specific locations from early June to the end of July. Hotspots of male spawners were found from mid-June to mid-July and then from mid-August to mid-September. The main spatial overlap between male and female spawner hotspots is located on the western slopes and the north of Skiff bank (along the 1500 m isobath) and in the north-western region (near the 500 m isobath). Our findings enabled the formulation of hypotheses concerning the ecological drivers influencing Patagonian toothfish spawning and emphasize the importance of considering seasonal localized closures to avoid mortality and disturbance during spawning
Electronics-free geophysical sensors optically interrogated over 50 km
No full textInternational audienc