peer reviewed | This study investigates essential (Mg, Ca, Fe, Mn, Cu, Zn, Se, Ni) and non-essential (Li, Be, Cr, Rb, Sr, Cs, Cd, Sn, Ba, and Pb) element concentrations and stable isotope (δ13C, δ15N, δ34S) compositions in feathers of Brown Boobies (Sula leucogaster) from three distinct Atlantic islands: the Archipelagos of Saint Peter and Saint Paul (SPSP), Abrolhos, and Cagarras. We aimed to investigate the ecological and environmental factors influencing these seabird populations and assess potential variations in contaminant exposure and dietary habits based on location, sex, and maturity stages. Our finding revealed significant geographical differences in trace element concentrations. The Brown Boobies from Cagarras had higher concentrations (mean ± SD, μg g-1) of Fe (29 ± 20) and Mn (0.82 ± 0.82) than those from Abrolhos (Fe: 21 ± 20; Mn: 0.24 ± 0.09) and SPSP (Fe: 15 ± 16; Mn: 0.21 ± 0.06). Tin concentrations were also higher in Cagarras (Sn: 0.02 ± 0.01) than in SPSP (Sn: 0.01 ± 0.01). Our analyses revealed significant differences in Li, Mg, Rb, and Zn concentrations between adults and juveniles. However, there were no sex-related differences in element concentrations within each locality. SIBER analyses revealed distinct dietary differences among the three Brown Boobies populations, with the Cagarras seabirds occupying a higher trophic position compared to the SPSP population. This study highlights the importance of considering different populations to understand contaminant exposure and ecological dynamics in Brown Boobies along the South Atlantic. The Cagarras population shows significantly higher contaminant levels, likely due to proximity to anthropogenic activities. These results highlight the necessity for ongoing monitoring to evaluate long-term effects on the more impacted population and to ensure seabird health and sustainability in the Atlantic Ocean.

peer reviewed | The application of biosolids can improve soil fertility and crop productivity but also accompanies risks of heavy metals and antibiotics introduction. In the presence of heavy metals contamination, using arbuscular mycorrhizal fungi (AMF) is a promising strategy to enhance soil microbial community stability and plant tolerance resistance to heavy metals, and to reduce the spread of antibiotic resistance genes (ARGs). The present study investigated the impacts of AMF inoculation on soil and plant heavy metal contents, and soil microbial communities by pot experiments. The results showed that AMF inoculation significantly enhanced plant biomass, and reduced soil and plant heavy metals contents. While AMF inoculation did not alter bacterial and fungal community compositions, it increased bacterial diversity at higher biosolids concentrations. Notably, AMF inoculation enhanced microbial network complexity and increased keystone taxa abundance. Furthermore, several beneficial microorganisms with high resistance to heavy metals were enriched in AMF-inoculated soils. Metagenomic analysis revealed a reduction in the mobile genetic element (MGE) gene IS91 in AMF-inoculated soils and an increase in heavy metal resistance genes compared to soils without AMF. The possibility of reduction in MGE-mediated spread of ARGs is one of the key findings of this study. As a caution, this study also detected enrichment of few ARGs in high biosolids-amended soils with AMF inoculation. Overall, AMF inoculation could be a valuable strategy in agriculture for mitigating the environmental risks associated with biosolids, heavy metals and antibiotic resistance, thereby promoting sustainable soil management and health.

The oxidative potential (OP) of particulate matter (PM) is considered a better health metric of PM exposure than mass concentration since its value is highly dependent on PM composition. OP assays have shown different sensitivities to PM components and particle sizes. In this work, an urban-industrial mixed site with high levels of airborne Mn and Fe, due to the proximity of a ferromanganese alloy plant, was chosen to study the association between PM elements and three OP assays (ascorbic acid (AA), dithiothreitol (DTT), and 2,7-dichlorofluorescein (DCFH)) in size segregated PM samples (PM10-2.5 and PM2.5). Urban samples from a nearby area were also collected. The concentration of 39 elements in both the soluble (in a phosphate buffer aqueous solution) and insoluble fractions of PM10-2.5 and PM2.5 was determined by ICP-MS. Soluble elements were then associated with OP and local sources using Principal Component Analysis (PCA). Four sources of soluble elements have been identified in the urban-industrial site. The main factor was attributed to road traffic; although Cu and Fe, two active transition metals in OP assays, were associated to this factor, their low solubility, mainly in the coarse fraction, has led to low factor loadings of OP; the second factor was attributed to a ferromanganese plant, since it presented the highest factor loadings for soluble Mn in both PM10-2.5 and PM2.5; it was the main factor associated with OP-DTT and OP-DCFH values, mainly in the coarse fraction. Crustal material and sea salt aerosol were also identified as sources. | This work was supported by the Spanish Ministry of Science and Innovation (Project PID2020-114787RB-I00, funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe”).

International audience | <div><p>Aquaculture is crucial in meeting global seafood demand; however, intensification often leads to bacterial diseases that threaten productivity. Dicentrarchus labrax, a key species in European aquaculture, is highly vulnerable to vibriosis, primarily caused by Vibrio harveyi. This study investigates genetic profiles associated with vibriosis by analyzing V. harveyi strains from a seabass farm during 2022 vibriosis outbreaks. Sampling from biofilm and water environments yielded 946 bacterial isolates, of which 56 were identified as V. harveyi using MALDI-TOF MS. ERIC-PCR genotyping revealed four distinct profiles. Despite observing variability in the presence of the 80 tested virulence genes, the overall genetic variation among these profiles was not pronounced. Notably, no single genotypic profile was linked to vibriosis. These findings suggest that the presence of virulence genes alone may not predict disease outbreaks, thus highlighting the need for future research on environmental and transcriptional factors to improve disease control in aquaculture systems.</p></div>

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.

International audience | Halong Bay (northern Vietnam) is heavily affected by human activities. Metals and metalloids (e.g., Al, Cu, Hg, Ni, Sb, Pb, V; MM) were used as proxies to assess the origin and transport of anthropogenic inputs. The chronology of inputs was examined according to different particle transport pathways using two sediment cores, one from coastal waters (HL) exposed to both atmospheric deposition and the Red River drainage, and the other from a small isolated lake on an islet (HT) receiving only atmospheric deposition. Higher accumulation rates were observed in HL (0.449 g cm -2 year -1 ) than in HT (0.069 g cm -2 year -1 ). In both cores, all anthropogenic MM fluxes are controlled by sedimentation processes regardless of their origin and transport pathways. Results show that coastal waters are strongly influenced by Red River drainage with specific events recorded in 1947 (Indochina War), 1960 (first five-year plan), 1974 and 1985 (flash flooding) and 2002 (Tuyen Quang Dam landslides). In HL core, the highest variabilities were observed for Cr, Hg, Ni, Pb and V with surface maxima of 67.7, 0.107, 26.0, 31.4, 82.2 µg g -1 , respectively. Geochemical ratios (Pb/Hg and V/Ni) showed specific signatures related to fossil fuel combustion. Estimated Pb deposition fluxes follow the increase in CO 2 emissions in the region.

International audience | The French Moss Survey employs forest mosses as indicators to monitor the deposition of atmospheric substances, notably focusing on cadmium (Cd), a known carcinogenic and contributor to respiratory illnesses. This comprehensive study encompasses 55 variables to understand Cd accumulation in terrestrial mosses in France. These variables include moss species, tree cover, biogeographical markers, land use area, proximity to road and rail networks, soil concentration of Cd and atmospheric concentration and deposition of Cd using a physical model. The response variable undergoes a complementary log–log transformation to constrain prediction values within the maximum Cd content in mosses. We have built a regression model to improve predictions, considering the impacts of covariates in France. This model retains biogeographical effects, leading to data segmentation into four distinct biogeographical zones: Atlantic, Continental, Mediterranean and Alpine. Subsequently, zone-specific regression models are explored to refine predictions and consider the impacts of covariates specific to each region, such as those related to railways and roads of the Mediterranean zone. Our biogeographical models effectively mitigate spatial correlation issues and yield accurate predictions, as evidenced by the leave-one-out cross-validation assessment. Compared to ordinary kriging map, the regression prediction maps highlight the contributions of certain covariates, such as the EMEP atmospheric transport model, to areas with high Cd concentrations. Furthermore, these maps exhibit new areas with high (resp. low) Cd concentrations due to high (resp. low) values of the covariates.

International audience | This review summarizes how salinity and temperature, two key global factors driven by climate change in freshwater systems, interact with other stressors on organisms in controlled small-scale factorial experiments at the population, individual, or subindividual level (excluding mesocosm and field studies). Despite the growing interest, research following all these criteria remains limited with 156 publications of which 50% analyzed stressors + salinity, 46% stressors + temperature, and only 4% involved the triple combination. Research on the combined effect of temperature and salinity predominantly focused on metals, pesticides, and, to a lesser extent, emergent contaminants, such as microplastics and nanomaterials, encompassing various biological models and responses. In general, increased temperature amplifies the single effect of stressors, whereas salinity leads to a higher diversity of responses, with similar proportions of synergisms and antagonisms. Fish (Salmoniformes, Perciformes, and Cypriniformes) were the most studied organisms. Among Crustacea, only cladocerans of the genera Daphnia and Ceriodpahnia were considered. The present review highlights the need to include other species that play key roles in freshwater food webs and to increase triple combination studies to understand complex interactions and develop adaptation and mitigation strategies to preserve the environment and its services in this changing world.

Numerous reviews have consistently highlighted the shortcomings of studies evaluating the effects of microplastics (MP), with many of the issues identified in 2016 still relevant in 2024. Here, we summarize the current knowledge on MP effect testing, compare guidelines, and provide an overview of risk assessments conducted at both single species and community levels. We discuss standard test materials, MP characteristics, and mechanisms explaining effects. We have observed that the quality of MP effect studies is gradually improving, and knowledge on enhancing these studies is available. Recommendations include data rescaling and alignment for ecological risk assessment, with preference for using environmentally relevant MPs. A step-by-step protocol for creating polydisperse test materials is provided. Most risk assessments indicate that concentrations observed in ecosystems globally exceed the effect thresholds measured in the laboratory. However, using a higher-tier approach, no risks are expected for freshwater benthic communities at current MP exposure concentrations. Evidence on the mechanisms behind adverse effects is growing; however, more well-designed experiments are needed. A potential solution might involve comparing natural particles with MPs that are as similar in dimensions as possible, providing insight into the mechanisms of food dilution where volume is a critical determinant of toxicity.

International audience | Surfactants are used for a variety of applications such as emulsifiers, solubilizers, or foaming agents. Their intensive production and use in pharmaceutical, cosmetic and agricultural products have resulted in their continuous discharge in the environment, especially via wastewaters. Surfactants have become a threat to living organisms as they interact with, and disrupt, cell membranes and macromolecules. Their effects have mainly been studied in aquatic species; however, terrestrial organisms are also threatened by these emerging contaminants. This study investigates the effects of two widely used nonionic surfactants, Tween-20 and Triton X-100, on key traits of larvae and adults of the fruit fly Drosophila melanogaster. We assessed the toxicity of the two surfactants on viability, development time, body size and food intake of the flies. The results revealed that both surfactants induced toxic effects on the drosophila flies leading to decreased viability, delayed development and lowered food consumption at the highest tested concentrations. Both surfactants proved to be toxic to flies, and, for all tested traits, Triton X-100 appeared more toxic than Tween-20. Our results might extend to other invertebrates. The widespread use of these substances, which then end up in the environment, should be regulated to mitigate their impacts on biodiversity and ecosystems.