A set of laboratory experiments was conducted to assess the trapping efficiency of buoyant plastic debris by the estuarine vegetation Spartina maritima. Different hydrodynamic conditions typical of salt marshes were simulated in a hydraulic flume. These conditions included varying water levels between 40% and 90% of stem height, wind speeds up to 2 m/s, and unidirectional current velocities between 0.1 and 0.3 m/s. Moreover, three vegetation densities (small/medium/high) and nine plastic debris types varying in shape (elongated/two-dimensional/three-dimensional) and size (macro/meso) were tested. The results indicate that Spartina maritima functions as a natural trap. Specifically, the study highlights that lower surface velocities, higher stem densities, greater emergent heights, and larger debris sizes significantly enhance trapping efficiency. It was also inferred that for a Spartina maritima density comparable to that observed in marshes, the dominance of surface velocity or debris size effects on trapping efficiency is primarily dependent on debris shape. Consequently, surface velocity has a greater impact on two-dimensional elements, whereas debris size is more significant for three-dimensional elements. Finally, a preliminary trapping model was developed to integrate all the aforementioned variables. This model has the potential to enhance the accuracy of numerical predictions regarding the transport and fate of plastic debris using Lagrangian modeling, and can be further refined by incorporating additional data. | The authors acknowledge the support of the Programa de Ciencias Marinas (PCM), funded by the Ministry of Science and Innovation of the Spanish Government and the Regional Governments of Andalucía, Baleares, Canarias, Cantabria, Comunidad Valenciana, Galicia, and Murcia (PRTR-C17⋅I1). This program, part of the ThinkInAzul I + D + i Complementary Plan, has provided essential funding for this research, in line with the 2030 Agenda for Sustainable Development and the Decade of the Oceans initiative. Moreover, this research was also partially funded by PID2021-127358NB-I00-MICIU/AEI/10.13039/501100011033 and by FEDER as a way of making Europe. Finally, we express our deep gratitude to Margot Sánchez for her invaluable support and dedication throughout the development of this work.

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.

Marine debris (MD) can be a transport vector for diverse marine communities, including non-indigenous species (NIS). This study assessed MD potential role as a substrate for colonization and dispersal vector for NIS in the Madeira Archipelago (NE Atlantic) by examining three MD categories: floating (FMD), seafloor (SMD), and beached (BMD). Opportunistic sampling, conducted in collaboration with local maritime stakeholders, documented MD sightings with photographs and GPS coordinates. A total of 92 MD items were inspected, revealing 108 fouling species across 11 phyla, with 13 % identified as NIS. SMD exhibited the highest proportion of NIS (9.6 %), followed by BMD (4.4 %) and FMD (3.9 %). Notably, the study provides evidence that FMD functions as both a substrate and a dispersal vector for NIS in Madeira waters. Combining biogeographic analyses, oceanographic modelling, and MD identification marks, this study highlighted the North Atlantic Subtropical Gyre's currents as key pathways, transporting MD items from the Wider Caribbean, the North American east coast, and the Iberian Peninsula to Madeira within 2–3 years. These findings emphasize Madeira's dual role as both a recipient and exporter of MD, with implications for NIS introductions and secondary spread. This study underscores the urgent need for standardized monitoring, stakeholder engagement, and proactive MD management strategies to mitigate NIS introductions and protect sensitive marine ecosystems like Macaronesia from the ecological risks of biological invasions.

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”).

peer reviewed | The Mediterranean seagrass species Posidonia oceanica forms extensive meadows that provide numerous ecological and economic services. Among the human activities threatening these meadows, boat anchoring causes severe degradation resulting in meadow fragmentation, exposure of the dead matte, and sediment disruption. In this study, we assessed the natural recolonisation dynamics of P. oceanica in anchoring-degraded sites focusing on both shallow and deep sites. Over two years, photogrammetry was employed to monitor recolonisation dynamics with a focus on patchs' edges expansion and storm-fragments accumulation. Our results show distinct recolonisation patterns between shallow and deep sites, with shallow patches displaying more variable dynamics of erosion and recolonisation, while deep patches showed slower but more consistent recovery. Additionally, the abundance of storm-fragments, primarily in shallow areas, suggests potential for enhanced recovery through natural trapping structures. Despite recent regulations reducing anchoring pressures, recolonisation rates remain insufficient to counteract the extent of degradation in a reasonable timespan. These findings underline the importance of designing tailored restoration strategies based on site-specific recolonisation potential: high-density transplantation with durable anchoring structures in shallow areas to withstand hydrodynamic forces, and more cost-effective solutions like iron staples in deeper areas. Additionally, the study supports the use of trapping substrates to retain storm-fragments in shallow sites to boost natural recolonisation. This approach is crucial for enhancing seagrass meadow resilience, especially within a context of climate change and increasing pressures on coastal ecosystems.

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.

peer reviewed | Since the dramatic air pollution peaks that prevailed in the course of the 20th century in Europe, effective environmental policies, along with major shifts in fuel usage, resulted in the substantial decrease of SOx and NOx pollution. At the interface between atmosphere and vegetation, epiphytic bryophyte floras responded by massive back-colonisation of formerly polluted areas. Whether extant concentrations of these pollutants are indeed too low to impact species distributions, and whether other pollutants today play a more important role remains, however, an open question. Taking advantage of an air quality monitoring network for a wide range of pollutants in southern Belgium, we implement here variation partitioning and embedded covariate selection to assess the contribution of current air pollutant loads to variations in epiphytic community composition relative to that of background environmental factors. Factors accounting for variation in species composition included, by decreasing order of importance, background environmental factors, major air pollutants (SOx, NOx, O3, fine particle matter), pollutants of agricultural origin (NH3, pesticides), and heavy metals. The substantially larger role played by background environmental factors over air pollution points to the efficiency of air pollution reduction policies, even for such sensitive organisms as epiphytic bryophytes. Ozone was the most important pollutant. Its ecophysiological impact on cryptogamic epiphytes remains poorly known, and the difference of its concentrations between urban and rural areas suggests that it may actually be interpreted as a land-use marker. Pesticides, whose impact on epiphyte floras was not previously assessed, marginally contributed to community composition and species distributions.

International audience | Bisphenol A (BPA) poses longstanding environmental concerns due to its widespread presence and recognized toxicity; however, its multigenerational ecotoxicity, in aquatic models such as water fleas, remains incompletely understood. This study examined the impact of sublethal BPA exposure on Daphnia magna across six generations, tracking changes in both life-history and population traits. Over the first five generations, BPA exposure produced minor and inconsistent effects on age at first oogenesis, age at first offspring production, growth rate, and fertility. The sixth generation exhibited prolonged oogenesis, delayed first offspring production, reduced body size, and decreased fertility, indicating delayed adverse effects. These multigenerational effects did not significantly alter population size or dynamics. Furthermore, BPA exposure did not affect feeding behavior in D. magna over six days, suggesting that food consumption-mediated mechanisms were unlikely a contributing factor. Our findings reveal BPA's delayed adverse effects on D. magna fitness, underscoring potential vulnerabilities for D. magna and other species under additional environmental stressors. These results support literature indicating that endocrine-disrupting chemicals can cause delayed and cumulative adverse effects on zooplankton descendants. Broadening multigenerational research to include a wider range of species, alongside sub-organismal analyses, is crucial to advancing regulatory frameworks and understanding underlying mechanisms.

International audience | Shredder organisms play a key role in rivers by feeding and fragmenting coarse organic matter that will then beexploited by other consumers. The effects of microplastics (MPs) on Gammarus sp., an ubiquitous genus offreshwater amphipods, and its shredding activity have been broadly investigated. However, the potentialbehavioral and physiological effects of different sizes of MPs on Gammarus sp. remain overlooked despite therecognized influence of MP size on MP toxicity. This study investigated the effects of a 28-day exposure to fourdifferent concentrations of two size fractions of PVC-microplastics (PVC-MPs), on Gammarus fossarum mortalityrate, feeding rate, assimilation efficiency, and expression of proteins involved in key processes. Increased mortalitywas observed for all treatments exposed to PVC-MPs, with higher mortality in the presence of smaller PVC-MPs at the highest concentration. No protein biomarker modulation was observed in presence of PVC-MPs,suggesting that no metabolic stress but direct physical damages of PVC-MPs might have led to the observedmortalities. No difference was observed for feeding rates, but a higher assimilation efficiency was measured forindividuals exposed to PVC-MPs, regardless of the concentration. This could be due to energy reallocation towardsdefense mechanisms or indicate a potential shift in digestive microbiota. This study highlighted thetoxicity of PVC-MPs, particularly of smaller sizes and even at relatively low concentration, for Gammarus fossarum.PVC-MP pollution may therefore alter the functional integrity of river ecosystems by reducing theabundance of shredder organisms and, subsequently, the process of leaf litter decomposition.