no cv yet
Main field of expertise:
Name of organisation:
Type of organisation:
Main project your organisation is involved with, in relation to (sub)tropical biodiversity:
SEAPROLIF project (ERA-NETBIOME). Diversity and functioning of coastal marine biomes under siege: implications of seaweed proliferations across three oceans www.seaprolif.ird.nc The project aims to i) establish the algal proliferation status of the red alga Asparagopsis using three complementary approaches including genetic analyses, metabolomic fingerprinting and study of the microbial communities associated to the alga and ii) to monitor the populations and their interaction with cnidarian assemblages by testing experimentally the Asparagopsis proliferation and the natural toxicity of the alga on coral health and its putative control by herbivory. Tens of samples were obtained from the consortium network, based on sampling and preserving protocols initially designed by the partnership. For phylogeny and phylogeography, various molecular markers have been developed from the three organelles for 76 specimens sampled in 53 sites within the 8 biogeographic regions. In addition mtDNA sequences were obtained from 308 specimens collected in New Caledonia, one important target site of the SEAPOLIF project. A new lineage in the two study species of the genus Asparagopsis has been identified. Microbial profiles associated to the alga are currently processed using the DGGE technique to check for spatial variations in respective of the genetic identity of the Asparagopsis host. Significant differences of the microbial community which did not match with the genetic variations among the Asparagopsis hosts have been revealed from various samples covering most genetic diversity. In the meantime, a protocol has been developed to analyze the metabolomic content of each collected sample and will be applied to 502 samples collected in 8 locations all around the world. Nowadays, two original and highly halogenated compounds harboring skeleton made of 6 carbons have been isolated and purified which add to the 150 halogenated compounds (1 to 4 carbons) already known. These compounds will be test to assess their putative role as mediator in the algal/coral interaction. Continuing the work we expect to fill knowledge gaps for a better understanding of the algal proliferation and to propose management measures for policy makers/managers.
Biodiversity and biogeography of marine, reef-forming red algal order Corallinales from western Pacific Ocean (BIOCCARA-ANR bilateral france-Taiwan ;2014-2017) The scientific question addressed in the project aims to measure accurately the species diversity of coralline algae from the coral reefs of three sites namely, Taiwan including the Orchid Island which is the jewel of this country, New Caledonia, a UNESCO World Heritage site with the second most extensive reef systems in the world, and Indonesia (Bali) which is located in the heart of the coral triangle where biodiversity is at its most higher expression.
Changement climAtique et Production carbonée des algues corallinacées des RécIfs CoralliEns (CAPRICE-LabEx-CORAIL) L'acidification des océans due à l’augmentation des émissions de CO2 dans l’atmosphère représente un risque majeur pour les organismes calcifiants en raison de la réduction des états de saturation en carbonate de calcium (CaCO3). Si les taux de calcification deviennent plus faibles que ceux de dissolution, les récifs coralliens pourraient basculer d’un régime d’accrétion positive à celui d’érosion positive, perturbant ainsi les processus et services écosystémiques associés aux récifs. Notre manque de connaissance sur la réponse des espèces calcifiantes au changement climatique est particulièrement criant pour les algues calcaires encroûtantes (ACE), et ce malgré leur importance. Nous proposons d’étudier l'effet du changement climatique sur la calcification et la dissolution des espèces clés, à partir d’incubations pendant 10 mois dans des aquariums pour des concentrations en CO2 et des températures actuelles et prévues pour 2100. La fiabilité des valeurs de croissance mesurées en aquarium sera testée par comparaison avec des valeurs de croissance obtenues sur des transplants in situ. Finalement, nous quantifierons comment le changement climatique pourrait affecter le bilan de carbone des ACE au niveau du récif corallien, en passant de l'espèce à la communauté récifale en utilisant des données d’abondance in situ.
Algal-coral interactions on coral reef ecosystem across multiple algal species and functional groups (join programme with Belgium, University of Ghent). Tropical coral reefs, the rainforests of the sea, feed a large portion of the world's population, protect tropical shorelines from erosion, and harbour a vast reservoir of biodiversity providing various goods and services critical to human societies (Moberg & Folke, 1999). Unfortunately, they are also among the most fragile ecosystems and are now beset by problems ranging from local pollution and overfishing to outbreaks of coral disease and overgrowth by macrophytes (Hughes et al, 2007; Bellwood et al, 2004). Most scientists agree that those threats all result in loss of biodiversity, of seascape complexity and associated services (Dodge et al. 2008). The losses are very often associated with shifts from coral to algal dominance, and macrophytes are recurrently suggested to play a major role in the decline (Done, 1992). McCook et al. (2001) reviewing the coral-algal interactions, proposed 6 mechanisms by which algae can compete with corals: 1/overgrowing, 2/shading, 3/abrasion, 4/allelopathy, 5/recruitment barrier and 6/epithallial sloughing. All those mechanisms have been more or less documented and the recent work of Rasher and Hay (2010) demonstrate the significance of chemical ecology in the coral-algal-herbivore interactions and the impact on coral reef. Numerous native as well as non-indigeneous algae (invasive species) have been involved in algal overgrowing and reef degradation and there are a limited number of reports of the reversal of the phase shifts (Stimson & Conklin, 2008). Several groups of macroalgae including Halimeda, Caulerpa, for the greens, Dictyotales (Dictyota, Lobophora, Padina) and Fucales (Turbinaria, Sargassum) for the brown and Acanthophora, Asparagopsis, Euchema, Gracilaria and Portieria for the reds are currently associated with algal blooms and coral reef degradation. In New Caledonia, various coastal shallow reefs and outer reef slopes are facing overgrowing of certain species of Halimeda, Dictyotales (Dictyota and Lobophora, Sargassum and Asparagopsis deeply changing the seascape in the affected areas. The aim of the project is 1/ to better document the phase-shift and to give a good mapping of the knowledge at a local (reef) and regional (island) scale, 2/ to precise the status of the species involved paying special attention to cryptic diversity and indigenous vs introduced algal species, 3/ to assess the outcomes and mechanisms involved in seaweed-coral competition across multiple seaweed species and functional groups.