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Coral recruitment in mesophotic coral ecosystems is lower and taxonomically distinct from shallow environments at Reunion Island, southwestern Indian Ocean
No full textInternational audienceCoral recruitment is an essential demographic mechanism that underpins the community structure and dynamics of coral reefs and facilitates post-disturbance coral recovery. However, information on coral recruitment patterns in mesophotic coral ecosystems (MCEs) is globally scarce, and no study describes patterns in the lower mesophotic zone (> 60 m depth). We quantified spatial variability in coral recruitment at shallow (15 m), upper (45 m) and lower (75 m) mesophotic depths across three contrasted locations (nine stations) around Reunion Island in the southwestern Indian Ocean. This study, the first to assess coral recruitment patterns on lower mesophotic habitats, highlighted a marked decline in recruitment rate in MCEs consistently across locations. Recruit composition varied significantly with depth, with Pocilloporidae dominating shallow habitats, while lower MCEs exclusively harbored “other” coral family recruits (i.e., other than Acroporidae, Pocilloporidae and Poritidae). Coral recruitment rate on tile surface orientation varied significantly with depth, with an overall higher proportion of recruits recorded on top surfaces at lower mesophotic depths. The abundance of Pocilloporidae recruits was positively correlated with confamilial adult coral cover, suggesting stock-recruitment or recruitment-limitation models for the dynamic of dominant shallow corals over a broad depth gradient. Upper MCEs could constitute substantial refuges for Pocilloporidae corals, while lower MCEs are of paramount importance for “other” coral families. Interannual surveys are necessary to better understand the spatiotemporal variability of coral recruitment in shallow habitats and MCEs and the driving forces of early post-settlement processes
Synthèse des connaissances sur les membracides et les aetalions de Guyane française (Hemiptera :Auchenorrhyncha : Membracidae, Aetalionidae). Partie II : biologie, plantes-hôtes et interactions écologiques.
No full textInternational audienceThis article reports on the knowledge of host plants and mutualistic interactions of membracids in French Guiana, based on six years of field surveys conducted between 2016 and 2023. Brief notes are presented regarding microhabitats, phenology, polyphagy, predation, and parasitism. Several hypotheses are proposed to explain evolutionary convergences and defense mechanisms. Additionally, a classification approach for membracids is introduced, based on ecological traits (degree of association with ants) and morphological characteristics (mimicry, shape of pronotal helmets).Cet article fait état des connaissances des plantes hôtes et des interactions mutualistes des membracides de Guyane suite à six années de prospection sur ce territoire entre 2016 et 2023. De brèves notes sont présentées concernant les micro-habitats, la phénologie, le polyphagisme, la prédation et le parasitisme. Quelques hypothèses sont proposées pour expliquer des convergences évolutives ou des mécanismes de défense. Une approche de classification des membracides selon des traits écologiques (degré d’affinités avec les fourmis) ou morphologiques (mimétisme, forme des casques) est également présentée
Sustainable fabrication of superhydrophobic glass using amorphous geothermal silica: A comparative study with commercial silica
No full textInternational audienceIn Guadeloupe, the Bouillante geothermal power plant supplies around 10% of the island’s electricitybut faces a recurring issue of silica (SiO₂) scaling. This occurs when dissolved silica in geothermal fluidsprecipitates due to changes in temperature, pressure, or pH [1]. Rather than viewing this amorphoussilica as an undesirable waste product [2,3], this study explores its potential as a sustainable alternativeto commercial silica for the development of superhydrophobic surfaces, particularly for seawaterdesalination applications. Silica samples collected from various locations within the geothermal systemexhibithed particle size ranging from 20 to 200 nm (SiO2 Bypass Basin ≃200 nm (SiBB-200), and SiO2Separated Water ≃20 nm (SiSW-20). They were then functionalized with OctadecylTrichloroSilane (OTS, C18H37SiCl3), a non-fluorinated hydrophobic agent, and compared to a commercial, non-porous colloidal silica ≃5 nm (SiVirgin). All coatings, applied via dip-coating on glass substrates, exhibited comparablesuperhydrophobic behavior with static water contact angles close to 162°(fig.1a-1b). However, geothermal silicas displayed distinct structural features. Silica deposits collected from the bypass basinexhibited lower porosity and more advanced polymerization than colloidal silica extracted fromseparated water. IR and 29Si NMR analyses confirmed higher surface –OH reactivity for geothermal samples compared to the commercial one. After functionalization, profilometry revealed surfaceroughness up to 500 nm (fig.2). Despite these differences, water-repellent performance remainedsimilar, indicating geothermal silica as a viable and sustainable alternative for high-performance surfacecoatings in desalination applications
Ant communities and urbanization: insights from tropical territories in French overseas regions
No full textInternational audienceUrbanization is a rapid ecological process that fundamentally reshapes biodiversity. As urban areas expand, species distributions and biotic interactions are altered, leading to biodiversity loss and biotic homogenization. This study investigates the impact of urbanization on ant communities across three tropical territories with distinct ecological histories: French Guiana, Guadeloupe, and Martinique. We hypothesized that increasing urbanization would decrease native species richness while facilitating the establishment of exotic species. Using citizen science initiatives to collect ant samples, we analyzed species richness, community composition, and co-occurrence patterns along urbanization gradients. Results showed that in French Guiana and Guadeloupe, urbanization significantly decreased species richness while the proportion of exotic species increased. Martinique exhibited no significant effect of urbanization on species richness or exotic species proportion. The patterns of beta diversity were driven by both nestedness and spatial turnover among urbanization levels within territories. Negative co-occurrences were predominantly observed between invasive species in all territories, particularly involving Pheidole megacephala , which showed exclusionary interactions with both native and other introduced species. Our findings underscore the complex, context-dependent effects of urbanization on biodiversity, highlighting biotic homogenization as a key consequence. These results provide valuable insights into the role of urbanization in shaping ant communities in tropical ecosystems
Squirrel reservoirs of monkeypox virus are sister species separated by the Sanaga River (Cameroon), as are the two main viral clades
No full textData availability: Raw reads used for assembling mitogenomes are available in NCBI Sequence Read Archive (Bioproject PRJNA1262415; Accessions: SAMN48453638-SAMN48453650). Annotated mitochondrial genomes are available in GenBank, accession numbers PV606393-PV606405. The DNA alignments are available in the Open Science Framework (OSF) platform at https://osf.io/m9ndq.International audienceHighlights: • Molecular polyphyly of a squirrel species reservoir of the monkeypox virus (MPXV). • New data on the distribution of the two squirrel species acting as MPXV reservoirs. • The species Funisciurus leucostigma is found to be endemic of West Africa. • The species Funisciurus anerythrus is found to be endemic of Central Africa. • The squirrel species are separated by the Sanaga River, as are the two MPXV clades.Abstract: Monkeypox is an emerging infectious disease of unclear zoonotic origin in Africa although increasing evidence suggests that rope squirrels are reservoirs of the monkeypox virus (MPXV).Here, we describe new data on the systematics of rope squirrels (Sciuridae, Funisciurus). Our molecular phylogeny strongly supports the polyphyly of Funisciurus pyrropus, with a Central African clade sister to Funisciurus leucogenys and a West African clade sister to Funisciurus anerythrus. Museum specimens show that the two clades have distinct pelage patterns. We propose therefore to resurrect the name Funisciurus leucostigma for the West African clade. Using reliable taxonomic identifications of georeferenced squirrels, we inferred the ecological niches of the three species of interest. The Sanaga River in Cameroon appears to be the barrier separating both the sister species F. anerythrus and F. leucostigma as well as the sister MPXV clades I and II. This suggests that these two MPXV clades were isolated in Central and West Africa, respectively, due to allopatric squirrel speciation
Poetics of Magmatism: Poïétique du magmatisme
No full textInternational audienceMagmatism and magnetism: two fundamental, subterranean forces that drive the unpredictability of the Relationship in the Middle Americas. Telluric, magnetic, and magmatic, this Relation, built on the polyrhythm of cultural clashes and the kairos of inaugural encounters, cuts through our traumatic aesthetics and confronts us with the ineffable inspiration of syncretism. When the veins of theater and poetry merge into a tumultuous artery, as evidenced by the intertwined echoes of Césaire, Walcott, and Brathwaite, an entire episteme is set in motion, an entire poetics of the verb embodied in the dancing flesh and the clamor of Creole languages that chant their cry through the arteries of cities where Carnival, Calypso, Bèlè, Ladja, and other oral traditions manifest the surge of diasporic creativity.Magmatisme et magnétisme : deux forces fondamentales et souterraines qui impulsent l'imprédictibilité de la Relation dans les Amériques du Milieu. Tellurique, magnétique et magmatique, cette Relation qui s'échafaude par la polyrythmie du choc des cultures, du kaïros des rencontres inaugurales traverse nos esthétiques traumatiques et nous confronte à l'ineffable inspiration du syncrétisme. Quand les veines du théâtre et de la poésie fusionnent en une artère tumultueuse comme en témoignent les échos imbriqués de Césaire, Walcott et Brathwaite, c'est tout un épistème qui se met en branle, toute une poïétique du verbe incarné dans la chaîr dansante et la clameur des langues créoles qui scandent leur cri à travers les artères des villes où le Carnaval, le Calypso, le Bèlè, le Ladja ou d'autres traditions orales manifestent le soubresaut des créativités diasporiques
L'intermélodicité dans l'oeuvre cinématographique de Raoul Peck: récits musicaux de résistance, de mémoire et d'identité postcoloniale
No full textInternational audienceThis article examines the concept of intermelodicity in the cinematic works of Haitian-born filmmaker Raoul Peck, focusing on how musical elements function as narrative metasporic devices that transcend conventional film scoring to become integral components of meaning-making. Through a comparative analysis of Moloch Tropical (2009), Lumumba (2000), I Am Not Your Negro (2016), this study demonstrates how Peck employs intermelodic strategies—the interweaving of multiple musical languages, genres, and cultural soundscapes—to construct complex narratives about postcolonial identity, historical memory, and resistance. We argue that Peck's intermelodic approach paves the way for a double process of sonic decolonization/metasporization, challenging Western cinematic conventions while creating new possibilities for representing and gathering Caribbean and African diasporic experiences. Drawing on musicological theory, postcolonial film studies, and cultural criticism, our contribution endeavors to show how sound operates as a political and aesthetic force in Peck's cinema, establishing connections between past and present, local and global, individual and collective memory.Cet article examine le concept d'intermélodicité dans les œuvres cinématographiques du réalisateur haïtien Raoul Peck, en se concentrant sur la manière dont les éléments musicaux fonctionnent comme des dispositifs métaphoriques narratifs qui transcendent la musique de film conventionnelle pour devenir des composants intégrants de la construction du sens. À travers une analyse comparative de Moloch Tropical (2009), Lumumba (2000) et I Am Not Your Negro (2016), cette étude montre comment Peck utilise des stratégies intermélodiques – l'entrelacement de multiples langages musicaux, genres et paysages sonores culturels – pour construire des récits complexes sur l'identité postcoloniale, la mémoire historique et la résistance. Nous soutenons que l'approche intermélodique de Peck ouvre la voie à un double processus de décolonisation sonore/métasporisation, remettant en question les conventions cinématographiques occidentales tout en créant de nouvelles possibilités pour représenter et rassembler les expériences diasporiques caribéennes et africaines. S'appuyant sur la théorie musicologique, les études cinématographiques postcoloniales et la critique culturelle, notre contribution s'efforce de montrer comment le son fonctionne comme une force politique et esthétique dans le cinéma de Peck, établissant des liens entre le passé et le présent, le local et le global, la mémoire individuelle et collective
Snapshots of coral reef biodiversity and challenges in a time of crisis
No full textInternational audienceCoral reefs are sanctuaries for a large portion of our planet’s biodiversity, but their rapid decline begs critical questions about what exactly is being lost, what are the driving forces that determine decline or resilience, and what are the implications for life on Earth. To address these questions, we synthesize the state of knowledge on the diversity of coral reef life forms at different scales of biological and ecological organization, encompassing variability in genes, biomolecules, cells, organs, organisms, populations, communities, ecosystems, socio-ecosystems, and biogeoclimatic systems, with a particular focus on French tropical overseas. We discuss research pathways to address knowledge gaps in various scientific disciplines, covering genetics (genomics, transcriptomics, proteomics, metabolomics), morphology, ethology, bio-acoustics, demography, functional ecology, macro-ecology, landscape ecology, human and social sciences, bioclimatology, and their cross-disciplinary interactions. Based on contributions from a team of coral reef experts working in coral reef regions spread around the world, our synthesis supports a better understanding of the various dimensions of coral reef biodiversity and proposes future research orientations for improving our knowledge of nature and its preservation. Given the rapid decline of coral reefs, and how much is still unknown, this work underscores the urgency of cross-scale biodiversity investigations for a systemic understanding of the drivers of biodiversity distribution and dynamics
