French Research Institute for Exploitation of the Sea
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Contrôle de surveillance DCE 2024 de la faune benthique de substrat meuble des stations d’appuis de la masse d’eau côtière « FRFC02 - Pertuis Charentais » : Rapport final.
No full textL’objet de ce document est de faire état des résultats des suivis stationnels des invertébrés benthiques de substrats meubles subtidaux et intertidaux réalisés en avril 2024 conformément au protocoles DCE de 2014 (Garcia et al., 2014) sur : - La station subtidale d’appui « Boyardville SM » suivie annuellement. - La station intertidale d’appuis « Les Doux int HZN » suivie annuellement
Rapport d’expertise sur les rapports d’état initial de l’environnement de la zone de parc éolien de Bretagne Sud (AO5)
No full textCe rapport d’expertise présente les observations de l’Ifremer sur les rapports de l’état initial de l’environnement de la zone de parc éolien de Bretagne Sud (AO5) réalisé par le bureau d’étude Setec sur deux années de suivi. Les rapports expertisés sont : Qualité de l’eau et des sédiments, Habitats et peuplements benthiques, Communautés planctoniques, Poissons, mollusques et crustacé
Seabird-derived nitrogen supply enhances photosynthetic activity in a reef-building coral
No full textNutrient subsidies from seabirds (SDN) significantly impact coral reef ecosystems, but access to remote seabird nesting islands limits our understanding of how corals respond to this nutrient source. This study investigates the in natura effects of SDN on coral metabolism at Surprise Island in the southwestern Pacific. Specifically, we examine how the photobiology of the ubiquitous reef-building coral Pocillopora damicornis responds to SDN availability. On Surprise Island, seabird-derived nitrogen follows a well-defined gradient across the land–ocean continuum and significantly contributes to scleractinian coral nitrogen uptake. At stations exposed to SDN discharge, seawater exhibited an elevated N:P ratio due to high nitrate concentrations as phosphate and ammonium concentrations remained similar to those at the reference station. Corals exposed to SDN-enriched coastal waters displayed a 50% increase in photosynthetic efficiency and a 40% increase in photosynthetic rate, coupled with a 115% increase in both symbiont density and chlorophyll concentrations. These findings demonstrate that nitrogen inputs from seabirds stimulate the photosynthetic activity of coral symbionts, highlighting the sensitivity of coral photophysiology to SDN. This underscores the critical link between seabird ecology and coral reefs functioning and emphasizes the need for integrated conservation efforts on coral islands
Fishery management amidst spatially differentiated ecological-economic externalities
No full textWe study management decisions made jointly and independently by countries affected by an invasive species that is also a profitable fishery. The Red King Crab, introduced in Russian waters of the Barents Sea, spread into Norwegian waters. Management by Russia and Norway reflects differing markets and invasion damages. Our spatial dynamic bioeconomic model evaluates management of the crab and optimal game strategies integrating varied incentives from market prices, ecosystem values, and spatial connectivity. Our empirical application characterizes stock changes responding to different model components. This research shows economic and ecological trade-offs in Arctic waters with differing net benefits for sovereign stakeholders
Qualitative modeling for representing the social-ecological system of the Groix–Belle-île offshore wind farm project
No full textThe increasing numbers of offshore wind farm (OWF) projects question the impacts of such infrastructures on the social-ecological system (SES) in which they are to be constructed. Some answers can be given using qualitative modeling and loop analysis. We used participatory modeling to co-construct a qualitative model of the socio-ecosystem together with stakeholders of the APPEAL project. The goal of the project was to evaluate the potential impacts of the pilot OWF in the Groix–Belle-île region. Then, loop analysis was used to study the characteristics of the SES created by the setting-up of an OWF. We focused on the impacts of SES variables on each other by evaluating their effects through direct and indirect pathways. Pleasure boating appeared as one of the SES components prone to suffer from the OWF construction, whereas industrial tourism was likely to benefit from it. This article presents the methodology used to obtain such results, for it to be used in spatial planning or in citizen-science processes
Influence of the phytoplankton community structure on the southern elephant seals' foraging activity within the Southern Ocean
No full textThe intricate relationship between trophic levels in marine ecosystems remains largely unexplored, particularly in the Southern Ocean. To investigate the complex composition of water constituents, notably the phytoplankton community, we used machine learning techniques to classify six bio-optical classes from a comprehensive ocean-color data time-series. In situ data from the Southern Ocean further characterized these classes by predominant phytoplankton types. Bio-logging data from southern elephant seals revealed that 60% of prey-catch attempts were concentrated within the diatom-dominated class, despite its lower regional frequency. Seals exhibited enhanced foraging activity and prolonged residency periods, up to 42 consecutive days, in diatom-rich waters compared to 5-10 days in other classes. These findings suggest a preference among southern elephant seals for diatom-rich waters, indicating a selective foraging activity influenced by the phytoplankton community’s structural composition rather than total biomass alone. This preference underscores the intricate interplay between marine top predators and ecosystem dynamics, hinting at mechanisms through which phytoplankton structure shapes seal activity
Including different mesozooplankton feeding strategies in a biogeochemical ocean model impacts global ocean biomass and carbon cycle
No full textMesozooplankton present a wide range of functionally diverse heterotrophic organisms ranging from 200 µm to 2 cm that are essential to marine ecosystems and biogeochemical cycles. In most ocean biogeochemical models, mesozooplankton are represented as a single compartment along with microzooplankton (< 0.2 mm), thereby overlooking their large functional diversity. Yet observational and modelling studies relying on functional trait-based approaches have shown how important the diversity of the functional traits of marine zooplankton is in driving ecosystem dynamics and biogeochemistry. Here, we use such a functional trait-based approach by modelling the effect of various mesozooplankton feeding strategies on the ocean carbon cycle globally, using the ocean biogeochemical model PISCES. Three new mesozooplankton functional types (PFTs) and their associated trade-offs were integrated in PISCES: cruisers (active swimmers feeding on suspension particles), ambushers (passive suspension feeder, relying on a sit-and-wait strategy) and flux-feeders (passively feeding on particles). An additional foraging effort for cruisers was implemented to account for the optimization of their active behaviour. Our new configuration shows that these functional groups have distinct latitudinal and vertical distributions: the two suspension feeding groups share the epipelagic zone, with ambushers being the dominant group at global scale (0.11 GtC/yr, 54.8 % of total mesozooplankton in the top 150 m) and cruise feeders (0.03 GtC/yr) prevailing in the productive regions near the poles, whereas flux-feeders (0.06 GtC/yr) dominate in the mesopelagic zone of coastal regions. We also demonstrate how the deep-dwelling flux feeders directly affect carbon export at depth more strongly by consuming the particles that would otherwise be transported to deeper layers (the carbon export increases by 40.8 % when flux-feeders are removed). This study provides more knowledge on functional diversity of mesozooplankton and emphasizes the necessity for a better integration of the trophic strategies of this planktonic compartment within global biogeochemical models
Assessing the chemical burden of the North-East Atlantic ecosystem through targeted and untargeted HRMS-based approaches
No full textHuman activities have introduced significant amounts of anthropogenic chemicals into marine ecosystems, posing threats to aquatic biodiversity and human health. Although, traditional marine monitoring focus primarily on legacy pollutants, the presence and potential risks associated with complex emerging chemical mixtures should not be neglected. In the context of the present study organized via OSPAR Commission and supported by NORMAN network, 52 marine samples were gathered from North-East Atlantic Ocean. State-of-the-art HRMS-based analytical workflows were employed to identify their chemical fingerprint. 132 organic pollutants were identified through wide-scope target screening of more than 2,400 environmentally relevant organic pollutants. The HRMS data were digitally stored in NORMAN DSFP and 134 additional chemicals were tentatively identified through suspect screening of more than 65,000 chemicals. The list included legacy pollutants, along with emerging pollutants and their metabolites and transformation products. A simplified environmental risk assessment was conducted, aiming to prioritize substances based on their potential risks to the marine ecosystem. This study provides a valuable snapshot of the marine pollution, offering insights into chemical occurrence and risks. The findings can support marine scientists, environmental managers and policymakers in identifying pollutant sources, understanding their impacts, and informing regulatory measures to mitigate threats to marine ecosystems