The aim of the MRSEI-CLIMAQS project is to set up a network of partners to prepare a project in response to the "HORIZON-CL6-2024-FARM2FORK-02-7-two-stage: Minimising climate impact on aquaculture: mitigation and adaptation solutions for future climate regimes" call for projects, which is of the "Innovative Action" type. Two projects will be funded for an overall budget of 9 million euros, and we would like to request 4.5 million euros for our CLIMAQS proposal. The evaluation will take place in two stages, the first of which will be blind, with a submission date of February 22, 2024. For the second stage, the complete project must be submitted by September 17, 2024. The CLIMAQS consortium plans to deploy multiple solutions around 6 workpackages to address the challenges of aquaculture in the context of climate change. The workpackages include solutions for diversification (WP1), innovative aquaculture systems and IMTA (Integrated Multi-Trophic Aquaculture, WP2), genetic selection (WP3), species nutrition (WP4), environmental monitoring and risk prevention (WP5) and aquaculture spatial planning (WP6). The various solutions proposed by the project partners will be tested through the implementation of case studies, and evaluated in terms of circular economy, economic, social and environmental sustainability, notably through socio-economic assessments (SHS) and life-cycle analyses in a 7th workpackage (WP7). The consortium currently comprises 7 organizations from 5 different European countries, with the French partner acting as coordinator. The coordinating group, comprising two researchers and a project engineer, has already been involved in a number of European projects at various levels of responsibility. More generally, the partners already identified are currently collaborating or have already collaborated in several European projects. However, to test and evaluate certain solutions, the network has identified a lack of skills in socio-economics, sociology, sustainable development and spatial planning, which we are seeking to identify and involve in our European project as part of this proposal to set up a European network. CLIMAQS will be designed to contribute to the expectations of the targeted call (Expected outcomes) and to the broader objectives (Expected impacts) of Cluster 6's Destination "Fair, healthy and environment-friendly food systems from primary production to consumption". The consortium has already identified a number of scientific and technical spin-offs, as well as economic, social, public policy and public perception impacts. Target groups have been identified, including aquaculture businesses, associations of professionals, environmental monitoring agencies, local authorities, European and national political players, civil society and consumers, and the scientific community. Indicators to measure these benefits are planned. All of this will be developed and specified in the plan for disseminating, exploiting and communicating the project's results. Following an initial video conference meeting in May 2023, two further face-to-face meetings are planned, mainly to optimize relations between partners and workpackages, the budget, and finalize the writing of the project to be submitted in February 2024. Expenditure for these two events is the most significant (missions, room hire and catering), to which have been added the costs of proofreading documents by an English-speaking scientist and the production of iconographies.

Understanding and forecasting the proliferation of holopelagic Sargassum in the tropical Atlantic requires progress in modeling the transport and biology of the macroalgae. Current models focus mostly on the transport part and base the biological part on relatively outdated knowledge for Sargassum fluitans or S. natans indistinctively. However, there is now strong evidence of the presence of three co-occurring morphotypes of Sargassum, with possibly different physiologies, and that the nutrients controling their growth may vary considerably among regions. Therefore we need to gain knowledge in the morphotype-specific response to varying environmental conditions and on the origin of nutrients in order to improve our capacity to simulate and forecast Sargassum biomass. The main objectives of BIOMAS are to acquire the necessary knowledge to build an individual-based model of Sargassum growth, to include that model into a drift model, and finally perform simulations of the integrated growth-drift model in order to forecast Sargassum morphotypes proliferation at seasonal scale. These objectives will be achieved through a strong synergy between laboratory experiments and modeling. The project is structured under : WP1, development of a growth model of Sargassum morphotyes based on the Dynamic Energy Budget (DEB) theory; WP2, laboratory experiments for calibrating the DEB model; WP3 in situ monitoring focusing on morphotypes and elemental composition in the Western and Eastern Atlantic; WP4, integration of the DEB model into a drift model and simulations. The consortium has expertise and experience in Sargassum biology, laboratory and field works, DEB and drift modeling, and is already involved in Sargassum research. Pan-Atlantic sampling will occur through the involvment of Brazilian, Mexican and African partners. The general public, including schools, will be engaged through a smartphone app that will serve both citizen science and results dissemination.

The inventory of marine biodiversity is carried out by direct observation, detection of activity (acoustics) or capture of living organisms, which is often difficult to implement due to the inaccessibility or ecology of the species. An innovative solution used worldwide (known as eDNA) is to collect a water sample in which the DNA fragments are filtered, amplified, sequenced and compared to genetic databases, thus enabling a list of the species present in the sampled environment. Currents, tides and waves contribute to the dispersal of eDNA, but studies show localized vertical and horizontal dispersal, allowing eDNA to give a picture of the species present in the study area. However, such sampling along a standard transect is likely to fail to detect DNA from mobile species that are absent or in low density at the time of water sampling. To address this limitation, this project will develop a method using passive eDNA sampling to inventory marine biodiversity (from bacteria to mobile megafauna), based on the use of submerged eDNA samplers to collect eDNA from the marine environment. Step 1 of the project is to develop prototypes of long-term stable passive eDNA samplers. Material shape, porosity, chemical composition and surface condition will be characterised in relation to DNA adsorption with both intra- and extracellular DNA. These prototypes will then be tested under increasingly complex conditions: (1) in mesocosms with increasing fish densities to test their ability to record these densities and as a function of water immersion times, (2) in a closed inlet to test the detection of low density species (sea turtle) and the fish community in comparison with the traditional eDNA transect/filtration method and (3) in a coastal lagoon communicating with the sea to test the detection of bacteria, phytoplankton and the fish community, also in comparison with the traditional eDNA method. Step 2 of this project aims to validate the detection of a mobile species by a passive sampler network. The experiment consists of secreting known DNA (with a variable secretion flux) from a boat that will perform different trajectories at different speeds to mimic the movement of a mobile species in a passive sampler array. In order to understand the dispersion of DNA between the donor (moving boat) and receiver (sampler network), the water circulation of the study area will be modelled by deploying measurement devices (radio equipped buoys). Step 3 will be the deployment of samplers in the natural environment (e.g., in offshore wind farms, marine protected areas) to assess their frequentation by mobile megafauna, by comparing the performance of passive samplers with classical (eDNA) and complementary (acoustic and video recordings) inventories. The water circulation of the studied area will be modelled (Lagrangian model), based on in situ measurements collected by a network of Acoustic Doppler Current Profilers (ADCP). The objective is also to evaluate the dimensioning of the protocol (number of samplers, distance between samplers, immersion time) in order to propose an optimised sampling plan. This clearly interdisciplinary project will considerably improve knowledge of the life cycle of eDNA (state, dispersion, adsorption), adapt an original methodology (passive samplers) to this rapidly expanding field (eDNA inventory) and thus improve the performance of marine biodiversity monitoring, which is currently under-detected.

Occurrence of microplastics (MPs) is documented in all terrestrial and aquatic environments at ever growing concentrations. Ingestion of MPs by fish has been massively reported whatever their ecological traits and living habitat. Long-term chronic exposures of marine organisms to MPs was shown to elicit physiological disruptions with consequences on life history traits (decrease in growth and reproduction), which may contribute to the endangerment of wild populations. Energy budget unbalance was suggested to contribute to these physiological disruptions but underlying mechanisms are not clearly identified. Further, gut microbiota is involved in many biological processes and its disruption upon exposure to MPs has been demonstrated (dysbiosis). It may be one of the pathways, additional to energy budget unbalance, leading to physiological effects. In addition, despite the fact that morphology of gastrointestinal tract appears to be unaffected by exposure to MPs, its protective and assimilation functions may be affected by exposure to MPs, as shown for example by changes in mucus abundance. These last disruptions may also contribute to metabolism and/or energy balance defects. Several initiatives emerged to mitigate emission of MPs and their effects on ecosystems. Among them are biodegradable polymers. Biodegradation is a complex process including several steps which require specific environmental conditions. Misuse or mismanagement of biodegradable items may result in biodegradable MPs (bMPs) ending in the marine environments. Biodegradation in nature also requires time (months to years) therefore release in the aquatic environment of biodegradable items supposed to be degraded (e.g. personal care products microbeads) may also contribute to high levels of bMPs. Very little is known about the toxicity of bMPs, especially when considering environmentally relevant exposure conditions. They may exert toxicity as conventional MPs do but their biodegradation properties may elicit specific modes of action toward organisms ingesting them and/or gut microbiota. It is then of utmost importance to evaluate their toxicity. In this context, the objectives of BIOMIC are to characterise the toxicity of two bMPs (PLA and PHBV) vs. a conventional MPs (PS) after chronic exposure of fish at environmentally relevant concentrations. Investigations will cover both individual and molecular levels to reveal defects concerning life history traits (growth, reproduction and behaviour) and energy balance (elementary analyses and metabolism genes expression). Over this long–term exposure, samples will be taken after 2-3 and 4-6 months of exposure to evaluate changes in intestinal microbiota (16S sequencing and metabolites) and intestinal function, including barrier function (e.g. mucus, histology). Attention will be paid to microbiota changes which may be polymer-specific. Finally, BIOMIC will evaluate if interactions of bMPs with organisms (gastrointestinal digestion process) and microbiota action influence erosion and fragmentation of bMPs which may in turn increases bMPs concentration and effects (e.g. using atomic force microscopy, size exclusion chromatography). Beyond increasing scientific knowledge, BIOMIC and its multidisciplinary consortium will be a valuable relay toward society, policy makers and stakeholders to raise awareness on the potential issues related with biodegradable plastic items.

Phytoplankton is an essential component in the functioning of marine ecosystems and in the carbon cycle. It is therefore essential to assess its variability and its main drivers. However, unlike seasonal and interannual variations, fluctuations of phytoplanktonic biomass and communities on decadal to multi-decadal timescales remain hampered by the lack of long-term observations at global scale and the uncertainties related to the complex balance of the processes that control their fate. These processes are imperfectly and diversely parameterized in biogeochemical models, limiting their use to document long-term phytoplankton variability. Yet, it is crucial to detect natural low-frequency cycles in phytoplankton biomass (and thus carbon fluxes) because they can enhance, weaken or even mask climate-related trends. In this context, the inter/transdisciplinary DREAM project proposes to investigate and benchmark different deep learning (DL) frameworks (learned from satellite and in situ observations) to emulate past and future multi-decadal time-series of surface phytoplankton biomass and communities. This approach will allow us to assess the relative contribution of the different processes (e.g. physical, predation, community structures) involved in phytoplankton dynamics over the last decades in response to natural climate low-frequency variability but also to past and future anthropogenic forcing. Ultimately, DREAM will also contribute to characterizing and better constraining the uncertainties in the climate projections of the different Earth System Models gathered in the Coupled Model Intercomparison Project Phase 6 (CMIP6).