International audience | Plastic pollution, a global threat to environmental and human health, is now ubiquitous in the environment, including agricultural soils receiving urban compost amendments. Yet, the accumulation pattern of microplastics in soils are still to be disentangled, with regards to their sources and/or their physical properties such as morphotypes. The aim of this study was to identify the accumulation patterns of coarse microplastics resulting from the long-term amendment of soil with urban waste composts. To this end, we used a field experiment receiving three different urban composts derived from municipal solid waste, biowaste, and a mixture of sewage sludge and green waste. We isolated 1417 coarse microplastic particles from a 21-year archive of soil and compost samples, using density fractionation followed by oxidation, and used Py-GC/MS for polymer identification. Different compost types led to different coarse microplastics accumulation levels. The accumulation pattern showed increasing CMP contents in soils over time. After 21 years of experiment, the calculated number of CMP was in accordance with the estimated values for all three compost types but it was not the case for the CMP mass. No difference of evolution pattern was found between films and fragments. We proposed that biotic transport or abiotic weathering and fragmentation could explain such differences in CMP evolution pattern.

International audience | Watersheds and estuaries are impacted by multiple anthropogenic stressors that affect their biodiversity and functioning. Assessing their ecological quality has consequently remained challenging for scientists and stakeholders. In this paper, we propose a multidisciplinary approach to identify the stressors in seven small French estuaries located in agricultural watersheds. We collected data from landscape (geography, hydrobiology) to estuary (pollutant chemistry) and fish individual scales (environmental signatures, proteomics). This integrative approach focused on the whole hydrosystems, from river basins to estuaries. To characterize each watershed, we attempted to determine the land use considering geographic indicators (agricultural and urbanised surfaces) and landscape patterns (hedges density and riparian vegetation). Juveniles of European flounder (Platichthys flesus) were captured in September, after an average residence of five summer months in the estuary. Analyses of water, sediments and biota allowed to determine the concentrations of dissolved inorganic nitrogen species, pesticides and trace elements in the systems. Environmental signatures were also measured in flounder tissues. These environmental parameters were used to establish a typology of the watersheds. Furthermore, data from proteomics on fish liver were combined with environmental signatures to determine the responses of fish to stressors in their environments. Differential protein abundances highlighted a dysregulation related to the detoxification of xenobiotics (mainly pesticides) in agricultural watersheds, characterized by intensive cereal and vegetable crops and high livestock. Omics also revealed a dysregulation of proteins associated with the response to hypoxia and heat stress in some estuaries. Furthermore, we highlighted a dysregulation of proteins involved in urea cycle, immunity and metabolism of fatty acids in several systems. Finally, the combination of environmental and molecular signatures appears to be a relevant method to identify the major stressors operating within hydrosystems.

International audience

International audience

International audience | Analyzing the environmental factors affecting benthic communities in coastal areas is crucial for uncovering key factors that require conservation action. Here, we collected benthic and environmental (physical-chemical-historical and land-based) data for 433 transects in Taiwan. Using a k-means approach, five communities dominated by crustose coralline algae, turfs, stony corals, digitate, or bushy octocorals were first delineated. Conditional random forest models then identified physical, chemical, and land-based factors (e.g., light intensity, nitrite, and population density) relevant to community delineation and occurrence. Historical factors, including typhoons and temperature anomalies, had only little effect. The prevalent turf community correlated positively with chemical and land-based drivers, which suggests that anthropogenic impacts are causing a benthic homogenization. This mechanism may mask the effects of climate disturbances and regional differentiation of benthic assemblages. Consequently, management of nutrient enrichment and terrestrial runoff is urgently needed to improve community resilience in Taiwan amidst increasing challenges of climate change.

International audience | The hydro-meteorological conditions in marine environments are recognized to have a major impact on the transport and dispersion of microplastics (MP), although their precise effects remain poorly understood. This study investigates the effects of tidal fluctuations on MP abundance and composition in a megatidal coastal water. Waters samples were collected every ninety minutes over the course of two complete tidal cycles – one during spring tide and another during neap tide. There were no significant disparities in term of abondance, size, and composition of MPs between the samples collected during the two tidal cycles. Nevertheless, MP abundance and characteristics (morphology, size and polymer types) can be influenced over the course of a complete tidal cycle due to the impact of tidal currents and water height. This study highlights the need to consider the fluctuations of the tidal cycle when planning in-situ surveys to better assess MP pollution in coastal environments.

International audience | Tracking PFAS in ecosystems is challenging. In this context, monitoring programs are crucial to fill data gaps, especially in marine environments, which are the ultimate outlets for these forever chemicals. The 2021 chemical contamination monitoring campaign along the French Mediterranean coast established a baseline for PFAS concentrations in mussels, with 90 % of measurements below quantification limits. When detected, long-chain PFCA's were predominant. Spatial distribution patterns suggested continuous PFAS inputs and complex dynamics, shaped by the influence of large watersheds and rivers (Rhône, Aude, Huveaune). Lapeyrade shallow lagoon stood out as the most contaminated site. Similar PFAS profiles in connected sites implied shared sources but raised questions about accumulation processes in mussels. While certain sites had evident sources (e.g., military airbase for Palo lagoon), others remained uncertain (e.g., Toulon bay). Coastal stations (Banyuls, Cap Agde, Brégançon, Pampelonne) showed PFAS contamination without clear onshore sources, possibly due to insufficient transportation process understanding.

International audience | Plastics are one of the major forms of anthropogenic pollution. This waste can affect the individual survival in many species, including seabirds. The Southern Ocean ecosystems are thought to be less affected by this pollution, due to the low human presence and the natural protective barrier provided by southern oceanic fronts. Here, we report the first observation of macroplastic ingestion in two dead King penguins (Aptenodytes patagonicus) in the Crozet archipelago located south of these fronts. There is no evidence that the macroplastic fragments found in their stomach were the direct cause of death.We suggest that they were ingested by being confused with stones they used for food grinding.Although it is difficult to assess the local or distant origin of these macroplastics, efforts to collect waste from sites as remote as the subantarctic islands must become standard practice to ensure that such ingestions do not become commonplace.

International audience | On September 26th 2019, a major fire occurred in the Lubrizol factory located near the Seine estuary, in RouenFrance. Juvenile flounders were captured in the Canche estuary (a reference system) and caged one month in the Canche and in the Seine downstream the accident site. No significant increases of PAHs, PCBs and PFAS was detected in Seine vs Canche sediments after the accident, but a significant increase of dioxins and furans was observed in water and sewage sludge in the Rouen wastewater treatment plant. The proteomics approach highlighted a dysregulation of proteins associated with cholesterol synthesis and lipid metabolism, in fish caged in the Seine. The overall results suggested that the fire produced air borne dioxins and furans that got deposited on soil and subsequently entered in the Seine estuarine waters via runoff; thus contaminating fish preys and caged flounders in the Seine estuary.