Towards the development of ecosystem-based indicators of mangroves functioning state in the context of the EU water framework directive

European Water Framework Directive is enforced in five tropical French Oversea Territories where mangroves are present. Developing bioindication tools to support the ecosystem-based management approach of the Directive is needed. A series of expert workshops was organized and led to the proposal of a strategy and of an applied research program to develop bioindication tools. The proceedings of the workshops are presented as a case study, as this is the first time such an integrative ecosystem-based approach is proposed in mangroves, combining structural and functional aspects, from forest structure to benthic community functioning

Microbial indicators of the mangrove functional state in French overseas territories : application to the EU water framework directive

De par leur localisation dans la zone côtière, les mangroves sont soumises aux variations de qualité des eaux côtières en relation avec les pressions liées aux activités humaines. Présentes dans dix territoires ultramarins, cet écosystème constitue un élément intéressant pour témoigner de la qualité des masses d’eau dans le cadre de la Directive européenne Cadre sur l’Eau (DCE) en Outremer. Dans le but de valider la pertinence de l’utilisation des mangroves comme écosystème sentinelle, le projet « DCE mangroves » a investigué au sein d’un gradient d’anthropisation différents compartiments biologiques afin d’améliorer la connaissance de la biodiversité et du fonctionnement de ces forets. Cette thèse a eu pour objectif de caractériser les communautés procaryotiques benthiques (biomasse moléculaire, abondance, diversité et composition) de mangroves afin (i) d’enrichir nos connaissances sur ces organismes clés, (ii) de comprendre quels sont les paramètres qui façonnent leur structure et (iii) de proposer des bioindicateurs potentiels des pressions anthropiques identifiées dans les mangroves ultra-marines étudiées. Les résultats obtenus ont permis (i) d’identifier les approches moléculaires adéquates à utiliser, (ii) de caractériser les pressions anthropiques exercées sur les mangroves de Guyane et Martinique, (iii) de compléter le référentiel sur la biodiversité des microbiotes des mangroves françaises et (iv) d’identifier des bioindicateurs microbiens potentiels de la dégradation des mangroves. Ces résultats constituent un socle pour la construction d’un indicateur utilisable pour déterminer la qualité des eaux côtières et de transition dans les outre-mer françaises.Due to its location, mangrove forests testify of the quality of the coastal waters and of the anthropic pressures in the littoral zone. Mangroves could therefore constitute a useful biological quality element to be used in the EU Water Framework Directive. To assess the use of mangroves for monitoring the water bodies in French overseas territories, a specific project, the “DCE mangrove project”, was created and funded by the French Biodiversity Agency. This project offered the opportunity to study the response and the functioning of French mangroves subjected to different types and levels of anthropic pressures. The global aims of this PhD were to characterize the French mangroves benthic bacterial and archaeal communities (molecular biomass, abundance, diversity and composition) in order (i) to improve our knowledge of these key organisms in mangroves functioning, (ii) to determine the drivers of mangrove microbiota, (iii) to identify several potential bioindicators of main anthropic pressures applied on mangrove forests. The results obtained to date have allowed (i) to select an appropriate molecular method to describe the benthic mangrove microbiota, (ii) to produce a detailed characterization of the anthropic pressures in several mangrove sites in French Guiana and Martinique island (West Indies), (iii) to start to build the microbial diversity reference system in French mangrove sediments and (iv) to identify potential microbial bioindicators of mangrove health. This work is a contribution to the establishment of a mangrove ecological indicator of the coastal and transitional water bodies qualities of the French oversea territories

Comparison of the goals and MISTELS scores for the evaluation of surgeons on training benches

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Oil Spill response in mangroves: why a specific Ecosystem-based Management is required? The case of French Guiana – a mini-review.

International audienceMangrove forests are formed by mangrove trees and shrubs that grow in the intertidal zone at the sea-continent interface. They constitute major ecosystems of tropical to subtropical muddy coasts that perform several ecological functions, including: mitigation of coastal erosion and flooding hazards associated with storm waves, extreme tides and tsunami, providing nurseries for some estuarine and coastal species (e.g. shrimps, fishes), production and recycling of organic matter, carbon storage, functioning as long-term sinks for several contaminants. World mangroves face a number of threats with increasing habitat destruction caused by direct and indirect anthropogenic pressures coupled with global climate change. They are known to be extremely vulnerable to oil spills. Even if the fate and impact of oil spills in such ecosystems have been partially monitored and experimentally studied (e.g. 30-year TROPICS field experiment in Panama islands, replicated field trials conducted in central Queensland, Australia) significant gaps in knowledge remain. The oil dynamic in such ecosystem is complex and depend of the abiotic-biotic processes interactions. Understanding the fate and impact of the oil spill thus requires an integrated approach of the functioning of the whole mangroves system facing the pollution. The case of the French Guiana mangroves, subjected to intense hydro-morpho-sedimentary dynamics under the direct influence of the massive discharge of suspended sediments from the Amazon River, will serve as conceptual model to highlight the importance of the need of a specific Ecosystem-based Management response in case of oil spill

Uncovering potential mangrove microbial bioindicators to assess urban and agricultural pressures on Martinique island in the eastern Caribbean Sea

International audienceMartinique's mangroves, which cover 1.85 ha of the island (<0.1 % of the total area), are considerably vulnerable to local urban, agricultural, and industrial pollutants. Unlike for temperate ecosystems, there are limited indicators that can be used to assess the anthropogenic pressures on mangroves. This study investigated four stations on Martinique Island, with each being subject to varying anthropogenic pressures. An analysis of mangrove sediment cores approximately 18 cm in depth revealed two primary types of pressures on Martinique mangroves: (i) an enrichment in organic matter in the two stations within the highly urbanized bay of Fort-de-France and (ii) agricultural pressure observed in the four studied mangrove stations. This pressure was characterized by contamination, exceeding the regulatory thresholds, with dieldrin, total DDT, and metals (As, Cu and Ni) found in phytosanitary products. The mangroves of Martinique are subjected to varying degrees of anthropogenic pressure, but all are subjected to contamination by organochlorine pesticides. Mangroves within the bay of Fort-de-France experience notably higher pressures compared to those in the island's northern and southern regions. In these contexts, the microbial communities exhibited distinct responses. The microbial biomass and the abundance of bacteria and archaea were higher in the two less-impacted stations, while in the mangrove of Fort-de-France, various phyla typically associated with polluted environments were more prevalent. These differences in the microbiota composition led to the identification of 65 taxa, including Acanthopleuribacteraceae, Spirochaetaceae, and Pirellulaceae, that could potentially serve as indicators of an anthropogenic influence on the mangrove sediments of Martinique Islan