HAL Collection UNC (Univ. de la Nouvelle Calédonie)
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Bleaching of Reef Organisms: Current Knowledge, Challenges, and Future Directions into the Anthropocene
No full textInternational audienceCoral reefs worldwide are threatened by climate change and other anthropogenic stressors. A global factor contributing to coral reef decline is the increasing frequency, duration, and intensity of bleaching events leading to extensive mortality of keystone species, which is caused by the loss of their photosymbionts under stressful conditions. The disruption of the symbiosis between scleractinian corals and their dinoflagellate algae has been the primary focus of bleaching studies. However, phototrophic microorganisms live in symbiosis with a diversity of non-scleractinian taxonomic groups, which have received less attention in the past. Here, we provide an overview of the current knowledge on the bleaching responses of a diversity of reef organisms, focusing on four symbiotic metazoan groups: scleractinian corals, sea anemones, giant clams, and sponges. We summarize the methods currently used to detect bleaching events at different spatial and temporal scales, the physiological and molecular mechanisms of bleaching, and the major hypotheses of bleaching. We provide future directions for the implementation of traditional and emerging protection strategies to increase the resilience of coral reefs to increasingly frequent and severe bleaching events. Finally, we discuss the potential for integrating state-of-the-art multi-omics tools to target multiple levels of organismal organization for future research on bleaching in complex coral reef holobionts
Light intensity modulates the effect of thermal stress on giant clams and their symbiotic zooxanthellae
No full textInternational audienceGradual climate change and extreme marine heatwaves (MHWs) pose a serious threat to tropical marine ecosystems, endangering the fisheries and aquaculture resources they support. A better understanding of species physiological responses to climate change-related stressors can help anticipate the risks and develop adaptive management strategies. While temperature is the main driver pushing organisms away from their optimal physiological and ecological performance, thermal stress is modulated by additional stressors in the wild, which cumulatively determine the extent of the impacts observed in nature. In this study we explored individual-level mechanisms driving the sensitivity of a symbiotic organism—the giant clam Tridacna maxima—to a range of temperatures (24, 27, 29, and 31 °C) and light intensities (150 and 1000 µmol m−2 s−1). After 18 days of exposure, we characterized the physiological response of both the symbiotic microalgae and the animal host using PAM fluorometry, respirometry, weight measurements, chlorophyll-a quantification, and measurements of zooxanthellae density and size. Our data revealed the crucial role of light in modulating the sensitivity of giant clams to warming. The effect of light and its interaction with temperature were stronger than temperature alone in driving responses of both the zooxanthellae (photosynthetic performance, zooxanthellae density and size, and oxygen production) and the host (respiration rate and condition index). By explicitly considering the interplay between temperature and light in photo-autotrophic organisms, aquaculture and fishery managers might have a tool for minimizing the impacts of climate change and MHW events on their activities
Making Peace With The Living: A Legal-Anthropological Perspective On Transitional Justice
No full textAlice BRITES OSORIO. Faire la paix avec le vivant: une perspective juridico-anthropologique de la justice transitionnelle. Università degli Studi di Trento. Grandi transizioni, vulnerabilità e ruolo del diritto = Les grandes transitions, vulnérabilités et rôle du droit, IRIS, 2025, 978-88-5541-123-3. ⟨10.15168/11572_463217⟩During armed conflicts, various activities can lead to environmental consequences, such as the destruction of places, soil and water contamination, among others. The use of certain weapons, like depleted uranium munitions, for example, can have long-term effects on living beings (both human and nonhuman) in conflict zones. Some conflicts are also driven by competition over 'natural resources,' which can lead populations to be displaced. The effects of war are experienced differently depending on the perspective of social groups. For non-Western cultures that have a relational connection with the non-human, armed conflicts affect human life but also the territories of which humans are a part. In other words, war often disrupts social structures and relationships, as well as socio-ecological relations.anthropological analyses demonstrate the first steps towards a way of conceiving law as a vector to rethink the transition from armed conflicts to peace, based on the concept of ecological solidarity, and towards a notion of transitional justice founded on the reparation of the eco-social network.</p
The environmental code of the Loyalty Islands: an example of successful legal crossbreeding?
No full textTheme 3. What are the ways of co-building knowledge in land-based and maritime production practices and small island food systems?International audienc
Des concepts et des ontologies : L’exemple du diptyque « Environnement-Nature » en France et au Japon
No full textInternational audienceL’étude compare les concepts « environnement » et « nature » en France et au Japon, révélant des différences ontologiques entre naturalisme occidental et animisme asiatique. Elle montre que ces notions, souvent confondues institutionnellement, traduisent des visions du monde distinctes : dualisme homme-nature en Occident versus monisme holistique en Asie. Les systèmes juridiques convergent vers une approche utilitariste, malgré des métissages culturels (ex. Nouvelle-Calédonie, Japon Meiji). Une enquête de terrain confirme la cohabitation des ontologies et leur influence sur la perception et la protection du vivant. Ces résultats ouvrent des perspectives pour un renouveau des grilles comparatives et du droit international de l’environnement
Coral genetic structure in the Western Indian Ocean mirrors ocean circulation and thermal stress
No full textGlobal warming and rising sea temperatures are pushing many reef-building coral species towards extinction. As thermal tolerance in corals is partially heritable, identifying genes under thermal selection is critical for targeted biodiversity management. However, it remains unclear how large breaks in connectivity (>100 km of open sea) affect the spread of adaptive alleles for different coral species in discontinuous reef networks such as the West Indian Ocean (WIO). To address this, we applied a seascape genomics approach to model (i) population connectivity and (ii) thermal adaptive potentials for two keystone coral species, Acropora muricata and Pocillopora damicornis, across the WIO. For both species, corals from the Seychelles were predominantly genetically isolated from corals in Rodrigues and Mauritius, putatively an effect of regional oceanographic barriers. Furthermore, sea currents during reproductive periods better predicted genetic connectivity than did Euclidean distances for both species, highlighting that connectivity models can serve as proxies to understand dispersal potential depending on reproductive strategies. Spatial patterns of neutral genetic variation were best explained by sea surface temperature variability and mean degree heating weeks. When used in genotypeenvironment association (GEA) analyses, we identified hundreds of loci under putative thermal selection from linked to known heat stress responses. In A. muricata, five Sacsin genes-cochaperones of the Hsp70 heat-shock protein involved in thermal stress response-were identified, alongside genes related to immune defence, antioxidant response, signalling, and protein folding. In contrast, only the centromere protein V, involved in mitosis, was enriched in P. damicornis. By integrating patterns of gene flow with molecular adaptations to estimate species-specific adaptive potentials, we found that large sea distances and strong oceanographic barriers inhibit the genetic exchange of adapted genotypes across the WIO, providing valuable insights to guide local and regional biodiversity management in this region..</div
Lustre of Crime : Convicts and New Caledonian shell art, 1864-1931
No full textInternational audienceThis presentation will put forward a lesser known part of Pacific island colonial heritage: convict carved shells from New Caledonia. The archipelago, a french penal colony between 1864 and 1931, was the destination for 22,000 criminals, among which existed skilled craftsmen, i.e. carvers, engravers, lithographs, etc.New Caledonian convicts established a system known as "débrouille", a series of small traffickings within the penitentiaries or in their close vicinity. Within the "débrouille" system, an industry of shell carving arose, "la camelote", which quickly became problematic for the local authorities. Once considered an anecdotic feature of the New Caledonian penitentiaries, a recent in-depth study of 1,000 pieces suggests a highly complex organization, from means of shell-harvesting to the carving and polishing phases, and for the first times establishes a definitive list of thirty convict artists, thus bringing a substantial addition to the archipelago’s art history.After a presentation of the origins and the rules regulating this activity, we will focus on the main iconographic themes involved in the artworks and present different categories of convict artists, in particular money counterfeiters and ex-military personnel from French colonial Algeria
Faire la paix avec le vivant: une perspective juridico-anthropologique de la justice transitionnelle
No full textInternational audienceArmed conflicts have significant environmental consequences: destruction of places, soil and water contamination, and population displacement due to com petition for natural resources. These impacts are experienced differently by var ious social groups. In non-Western cultures with a close relationship to the non human, wars disrupt not only human social structures but also socio-ecological relations. Our analysis explores the socio-ecological implications of recognizing non-human living beings as victims of conflict to support a transition toward peace. Through case studies in Colombia and East Timor, combining legal anal ysis and field research, we rethink the notions of reparation and reconciliation. Juridico-anthropological analyses demonstrate the first steps toward conceiving law as a vector for rethinking the transition from armed conflicts to peace based on the concept of ecological solidarity and a notion of transitional justice rooted in the repair of the eco-social fabric.Les conflits armés entraînent des conséquences environnementales importantes: destruction des lieux, contamination des sols et de l’eau, ou encore déplacements de populations liés à la compétition pour des ressources naturelles. Ces impacts sont vécus différemment selon les groupes sociaux. Dans les cultures non occidentales ayant une relation étroite avec le non-humain, les guerres perturbent non seulement les structures sociales humaines, mais aussi les relations socio écologiques. Notre analyse explore les implications socio-écologiques de la re connaissance du vivant non-humain comme victime des conflits, en vue d’une transition vers la paix. À travers des études de cas en Colombie et au Timor Oriental, combinant analyses juridiques et recherches de terrain, nous repensons les notions de réparation et de réconciliation. Les analyses juridico-anthropologiques font la preuve des premiers pas vers une manière de concevoir le droit comme vecteur pour repenser la transition des conflits armés vers la paix à partir du concept de solidarité écologique, vers une notion de justice transitionnelle qui a comme base la réparation du tissu éco-social.I conflitti armati comportano importanti conseguenze ambientali: distruzione dei luoghi, contaminazione del suolo e dell’acqua, o anche spostamenti di popo lazioni legati alla competizione per le risorse naturali. Questi impatti vengono vissuti in modo diverso a seconda dei gruppi sociali. Nelle culture non occiden tali, che hanno un rapporto stretto con il non-umano, le guerre sconvolgono non solo le strutture sociali umane, ma anche le relazioni socio-ecologiche. La nostra analisi esplora le implicazioni socio-ecologiche del riconoscimento degli esseri viventi non umani come vittime dei conflitti, in vista di una transizione verso la pace. Attraverso lo studio di casi in Colombia e a Timor Est, che combinano analisi giuridiche e ricerche sul campo, ripensiamo le nozioni di riparazione e riconciliazione. Le analisi giuridico-antropologiche dimostrano i primi passi verso un modo di concepire il diritto come strumento per ripensare la transizione dai conflitti armati alla pace, a partire dal concetto di solidarietà ecologica, verso una nozione di giustizia transizionale che abbia come base la riparazione del tessuto eco-sociale
Country scale assessments of coastal fish communities and drivers for sustainable socio-ecosystem management
No full textInternational audienceTropical coastal marine ecosystems, such as coral reefs, mangroves, and seagrass beds, harbor a significant portion of marine biodiversity and productivity, providing essential ecosystem services to human societies, including food and fisheries resources. However, global changes are causing rapid degradation of these ecosystems, resulting in the loss of ecological functions, habitats, and resources, which threaten both ecosystems and human societies. Successful examples of localized ecosystem and resource management exist, but generalizing these at larger, country and regional scales, which are relevant to strategic decisions, remains challenging. Identifying appropriate management measures is often difficult because ecosystem resilience is driven by various ecological processes that can be disrupted by a multitude of environmental stressors, including local pressures from fishing, habitat degradation and destruction, and global climate change, whose prevalence can vary across sites and species. We use a country-scale collaborative science approach to quantify long-term changes in fish communities, assess the efficiency of current management, and identify critical stress thresholds for sustainable management in the broad and biodiverse coastal system of New Caledonia. Our analyses characterize the distribution, composition, and abundance-biomass trajectories of key fish communities at various scales around the archipelago to shed light on local management successes and failures, as well as the mechanisms underlying resilience, to advise management decisions. Carried out in close collaboration with local communities, this work contributes to the development of sustainable management and conservation plans for New Caledonia’s exceptional coastal marine ecosystems and fish resources, which are listed as a UNESCO World Heritage site
Récifs coralliens, joyaux de biodiversité
No full textColorés et d'une grande beauté, les récifs coralliens du parc naturel de la mer de Corail forment de véritables forêts sous-marines. Ces univers complexes, encore large-ment méconnus, abritent une biodiversité exceptionnelle, où chaque élément structurant et chaque communauté biologique joue un rôle fondamental dans l'équilibredes écosystèmes. Bien qu'éloignés de la plupart des activités humaines et bénéficiant d'une haute protection, ces récifs sont aujourd'hui menacés par le réchauffementclimatique et des épisodes successifs de blanchissement. Face à ces dangers, les scientifiques de divers horizons collaborent pour mieux comprendre ces écosystèmeset anticiper les transformations à venir. Quelles espèces peuplent ces récifs ? Existe-t-il des connexions entre les récifs éloignés ? Comment ces récifs réagissent-ils aux canicules marines ? Quels sont les impacts passés et actuels de l'humain sur ces récifs éloignés ? Quelles relations entretient-il avec ces récifs ? C'est à cesquestions que ce chapitre tente d'apporter des éléments de réponse en s'appuyant sur de nombreuses expéditions naturalistes et études scientifiques faisant appelà diverses disciplines