Since 2011, massive strandings of holopelagic Sargassum have occurred on the coasts of the Caribbean and of West Africa. Although open ocean Sargassum mats are oases of biodiversity, their stranding has a number of negative ecological, economic and health consequences. To limit these impacts, Sargassum needs to be collected as quickly as possible to avoid its decomposition, which requires accurate predictions of the date, location and abundance of the strandings. Two complementary approaches have been developed for this purpose: satellite remote sensing technique, to detect Sargassum aggregations, and modeling, to forecast Sargassum displacement and growth. The objective of this review is to provide a synthesis of the current knowledge related to Sargassum monitoring in the tropical Atlantic Ocean. To better understand the issues surrounding Sargassum and its monitoring, the first two parts are devoted to an overview of the ecology of the two most prevailing holopelagic Sargassum species, to the current issues related to their strandings, to the causes of their occurrence in the tropical Atlantic Ocean and to their seasonal and interannual variabilities. The methods used to detect Sargassum from satellite images and their limitations are examined. The transport and biogeochemical models developed for seasonal forecast and stranding predictions are described along with their limitations. As both detection and modeling rely on validation data to assess their accuracy, previous works providing in situ characterization of Sargassum are also reviewed here. The last part provides recommendations to further increase knowledge on holopelagic Sargassum and improve the predictions of their strandings.

Fishing gears are designed to catch marine species, but when lost at sea, they can continue to trap and kill aquatic life, a phenomenon known as ghost fishing. This study evaluated the use of a biodegradable twine made from poly(butylene succinate)/poly(butylene adipate terephthalate) (PBS/PBAT) in trawl fishing. The assessment included mechanical testing, trawl modelling, and seawater ageing simulations to explore potential loss scenarios. Mechanical tests indicated that the PBS/PBAT braid was about half as strong as high-density polyethylene (HDPE) but was suitable for braiding and netting. After 3 years in seawater, PBS/PBAT monofilaments showed biotic degradation, with strength losses of 20 % at 15 °C and 80 % at 25 °C. This suggests that gear made from this polymer would degrade faster than conventional gear if lost. Trawl modelling further demonstrated that trawl performance was only slightly affected by material change and ageing, highlighting the potential for reducing ghost fishing with less persistent twine.

Offshore wind energy may offer many advantages: next to the aim of renewable energy production, offshore wind farms (OWFs) enable multi-purpose opportunities with nature conservation and aquaculture. OWFs may also affect the marine ecosystem. The environmental impact of OWFs is starting to be investigated regarding the effect of novel habitat introduction, underwater noise, electromagnetic fields, or exclusion of fisheries. However, the impact of chemical emissions from OWFs remains largely unknown. It is essential to account for these emissions at an early stage, to comprehensively assess the environmental impact with the objective of developing a future fit-for-purpose regulatory framework to protect the marine environment. This review compiled a literature-based list of potential OWF-related chemical emissions containing >200 organic and inorganic contaminants, including polymers. Compounds are categorised according to data source and emission type. Major gaps in assessing the impact of the compounds are identified, including challenges in environmental monitoring, numerical modelling and assessing the toxicity of individual and mixtures of chemical contaminants on marine organisms and humans consuming potential OWF aquaculture products. A risk-based prioritisation is essential to target the compounds of higher concern and overcome costs linked to assessing a wide variety of chemical contaminants. Although some countries have regulations to reduce OWF chemical emissions, standardized impact assessments or monitoring requirements for OWF-based chemical contaminants have not been established. This stresses the importance of providing more detailed information on occurrence, distribution and impact of OWF chemical emissions as an essential step towards sound ecosystem-based management of OWF installations.

The New Caledonian archipelago is an important hotspot of marine biodiversity. Due to mining activities, urbanization, and industrialization, significant amounts of contaminants are discharged into the lagoon. This study analysed the concentrations, spatial distribution, and potential drivers of 14 metallic compounds and trace elements (MTEs) and 22 persistent organic pollutants (POPs) in ~400 coral reef fish sampled from various sites around New Caledonia, across a gradient from mining centers to remote, uninhabited locations. Boosted regression trees modelling explained between 61 and 86 % of the global variation in MTEs and POPs concentration. Fish body size emerged as the most important correlate of MTEs and POPs concentrations in coral reef fish. Monthly rainfalls were the second most important variable for POPs, whereas the reef area was the second variable explaining MTE concentrations. Our modelling approach allowed us to predict and map the distribution of concentrations at the fish community level for 17 contaminants (9 MTEs and 8 POPs). Predicted concentrations ranged from ~1.5 ng.g−1 (β-endosulfan) to ~11.5 μg.g−1 (Ni), and revealed a widespread contamination throughout the lagoon, from the coast to the barrier reef. Contamination by mining-related elements (Ni, Cr…) were clearly influenced by the surface area of mining registry and to lithology to a lesser extent, whereas Hg contamination strongly depended on biological variables. Our study is the largest of its kind at the archipelago scale, combining data on 36 contaminants in ~400 fish samples with a modelling framework offering insights into underlying processes and spatial data for policy use.

Littoral environments represent the main entry point for pollutants into the sea. Microplastics (MPs) are a growing concern, especially for the Mediterranean basin characterized by densely populated coasts and a semi-enclosed morphology. This article targets MPs associated with a unique coastal habitat - the largest bioconstruction in the Mediterranean (Torre Mileto, Southern Adriatic Sea) built by the reef-building polychaete Sabellaria spinulosa (anellida). We assessed MPs abundance in samples from both bioconstruction and surrounding sediments using stereomicroscopy with UV light and micro-Raman spectroscopy. MPs distribution was analyzed according to substrate (reef vs. sediment), longshore drift (west vs. east side), and reef morphology (hummock vs. platform). Results showed a significantly higher MPs abundance in samples from the western side of the site, potentially related to a longshore drift influence on pollutant distribution. By contrast, no significant differences in MPs abundances were observed in substrates (reefs vs. surrounding sediments) and in reef morphologies (hummock vs. platform), which suggest no direct control of reef-building activity in accumulating MPs. The passive accumulation of MPs, primarily driven by wave action, is likely the main factor explaining the MPs distribution. Micro-Raman Spectroscopy analysis revealed polyethylene terephthalate as the dominant polymer, and fibers as the most abundant morphology; prevalent MPs colors were colorless and black. Data provided here indicate that polychaete reefs temporarily trap MPs, retaining such pollutant in the littoral environment. The mechanism of MPs passive accumulation observed in this study raises questions about the growing risk for this bio-engineered benthic habitats.

Preserving biodiversity against the adverse effects of plant protection products (PPPs) is a major environmental and societal issue. However, despite intensive investigation into the ecotoxicological effects of PPPs, the knowledge produced remains fragmented given the sheer diversity of PPPs. This is due, at least in part, to a strong streetlight effect in the field of ecotoxicology. Indeed, while some PPPs have been investigated in numerous ecotoxicological studies, there are many for which the scientific literature still has little or no information on their ecotoxicological risks and effects. The PPPs under the streetlight include a large variety of legacy substances and a more limited number of more recent or currently-in-use substances, such as the herbicide glyphosate and the neonicotinoid insecticides. Furthermore, many of the most recent PPPs (including those used in biocontrol) and PPP transformation products (TPs) resulting from abiotic and/or biotic degradation are rarely addressed in the international literature in the field of ecotoxicology. Here, based on a recent collective scientific assessment of the effects of PPPs on biodiversity and ecosystem services in the French and European contexts, this article sets out to illustrate the limitations and biases caused by the streetlight effect and numbers of gray areas, and issue recommendations on how to overcome them.

The application of plant protection products (PPPs) may have delayed and long-term non-intentional impacts on aquatic invertebrates inhabiting agricultural landscapes. Such effects may induce population responses based on developmental and transgenerational plasticity, selection of genetic resistance, as well as increased extirpation risks associated with random genetic drift. While the current knowledge on such effects of PPPs is still scarce in non-target aquatic invertebrate species, evidences are accumulating that support the need for consideration of evolutionary components of the population response to PPPs in standard procedures of risk assessment. This mini-review, as part of a contribution to the collective scientific assessment on PPP impacts on biodiversity and ecosystem services performed in the period 2020–2022, presents a brief survey of the current results published on the subject, mainly in freshwater crustaceans, and proposes some research avenues and strategies that we feel relevant to fill this gap.

Preservation of biodiversity and ecosystem services is critical for sustainable development and human well-being. However, an unprecedented erosion of biodiversity is observed and the use of plant protection products (PPP) has been identified as one of its main causes. In this context, at the request of the French Ministries responsible for the Environment, for Agriculture and for Research, a panel of 46 scientific experts ran a nearly 2-year-long (2020–2022) collective scientific assessment (CSA) of international scientific knowledge relating to the impacts of PPP on biodiversity and ecosystem services. The scope of this CSA covered the terrestrial, atmospheric, freshwater, and marine environments (with the exception of groundwater) in their continuity from the site of PPP application to the ocean, in France and French overseas territories, based on international knowledge produced on or transposable to this type of context (climate, PPP used, biodiversity present, etc.). Here, we provide a brief summary of the CSA’s main conclusions, which were drawn from about 4500 international publications. Our analysis finds that PPP contaminate all environmental matrices, including biota, and cause direct and indirect ecotoxicological effects that unequivocally contribute to the decline of certain biological groups and alter certain ecosystem functions and services. Levers for action to limit PPP-driven pollution and effects on environmental compartments include local measures from plot to landscape scales and regulatory improvements. However, there are still significant gaps in knowledge regarding environmental contamination by PPPs and its effect on biodiversity and ecosystem functions and services. Perspectives and research needs are proposed to address these gaps.

International audience | Preservation of biodiversity and ecosystem services is critical for sustainable development and human well-being. However, an unprecedented erosion of biodiversity is observed and the use of plant protection products (PPP) has been identified as one of its main causes. In this context, at the request of the French Ministries responsible for the Environment, for Agriculture and for Research, a panel of 46 scientific experts ran a nearly 2-year-long (2020-2022) collective scientific assessment (CSA) of international scientific knowledge relating to the impacts of PPP on biodiversity and ecosystem services. The scope of this CSA covered the terrestrial, atmospheric, freshwater, and marine environments (with the exception of groundwater) in their continuity from the site of PPP application to the ocean, in France and French overseas territories, based on international knowledge produced on or transposable to this type of context (climate, PPP used, biodiversity present, etc.). Here, we provide a brief summary of the CSA's main conclusions, which were drawn from about 4500 international publications. Our analysis finds that PPP contaminate all environmental matrices, including biota, and cause direct and indirect ecotoxicological effects that unequivocally contribute to the decline of certain biological groups and alter certain ecosystem functions and services. Levers for action to limit PPP-driven pollution and effects on environmental compartments include local measures from plot to landscape scales and regulatory improvements. However, there are still significant gaps in knowledge regarding environmental contamination by PPPs and its effect on biodiversity and ecosystem functions and services. Perspectives and research needs are proposed to address these gaps.

Incidental studies of plastic ingestion by the northern fulmar (Fulmarus glacialis) over a wide geographical range can improve our understanding of the distribution of marine litter in the global oceans and of the processes involved. A sample of 37 stomachs from northern fulmars (Fulmarus glacialis) collected in June 2021 near Flemish Cap at the eastern end of the Grand Banks of Newfoundland was analysed for the presence of plastic litter. Overall, 89 % of the birds contained plastic, with on average 6.6 particles, and a mass of 0.093 g per bird. No statistical differences were found in the quantity of plastic between males and females. A proportion of 27 % of all birds contained >0.1 g plastic, exceeding the Fulmar Threshold Value (FTV%) and international target of <10 %. Within an existing model that linked plastic abundance to latitude, the Newfoundland sample represented a clear outlier with a considerably lower FTV% compared to what would be expected. Flemish Cap is situated at the border between the southern tip of the cold and relatively clean Labrador Current coming from the north, and the warm and more polluted waters of the Gulf Stream further south. A logistic model using average annual sea surface temperatures representing North Atlantic current systems was applied and demonstrated a highly significant correlation, with the Newfoundland FTV% fitting much closer to the modelled prediction. This new model improves the understanding of geographical patterns in plastic uptake by fulmars