Copper (Cu) is an essential metal capable to alter many metabolic and physiological processes in animal species, depending on the environmental concentration and salinity. The present study evaluated the effects of Cu exposure on the metabolism of the blue crab Callinectes sapidus under different osmotic situations. Crabs were acclimated at two different salinities conditions (30 and 2). Subsequently, they were exposed to Cu during 96 h at each salinity and under hypo-osmotic shock. Results demonstrated that Cu exposure increased whole-body oxygen consumption. In addition, the activity of LDH decreased while citrate synthase increased in anterior gills from animals submitted to hypo-osmotic shock. This scenario indicates extra stress caused by sudden environmental osmotic changes, as commonly observed in estuarine environments, when combined with copper exposure. Therefore, the activity of LDH and citrate synthase enzymes might be sensitive indicators for aquatic toxicology studies approaching Cu contamination in estuarine environments.

The studies of the formation of oil-Suspended Particulate Matter (SPM) aggregates (OSAs) have advanced significantly in the scientific community, however there is a need to accelerate oil biodegradation that was dispersed by the formation of OSAs. The present research presents a pioneering character regarding the addition of nutrients as biostimulus for autochthonous hydrocarboclastic bacteria in the biodegradation of Total Petroleum Hydrocarbons (TPH) dispersed by the formation of OSAs. Water aliquots were taken over 60 days from eight bioreactors to perform ionic species analysis, pH, salinity and temperature monitoring, liquid/liquid extraction, serial dilution methodology and filter membrane. TPH quantification was performed on the gas chromatograph with a flame ionisation detector (GC-FID). The addition of nutrients contributed positively to the rate and extent of biodegradation of TPH in association with field-collected SPM. The best result found was with the lowest nutrient concentration (Bio 1) with an average of 98.65% of TPH reduction.

This study is focused on delivery and fate of floating marine litter (FML) carried by rivers to coastal sea. We examine a large flooding event which happened in the northeastern part of the Black Sea in October 2018. A high resolution circulation model coupled with a Lagrangian particle model is applied to simulate transport of riverine FML in the coastal sea. During this flood multiple river plumes in the study area coalesced into one stripe of freshened water which occupied large segment of coastal sea along the shoreline. Riverine FML was transported within this stripe far off its sources in river mouths and remained arrested near the shore. As a result, approximately half of the discharged FML was washed ashore by the Stokes drift. FML, which remained in the sea, accumulated at convergence lines associated with large salinity gradients at the fronts between the river plumes and the ambient sea.

This study reports on the ingestion of microplastics by the alien fish Pirapitinga, Piaractus brachypomus (Characiformes; Serrasalmidae) that escaped Vembanad lake, the largest brackish water lake in the south-west coast of India, from the aquaculture systems during flooding. Microplastics separated from the gut of 32 out of the 123 fishes (26%) examined were identified using Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR), and Raman Spectroscopy. In total, 69 microplastic particles, represented by fibers, foam and fragments were recovered from the fish, with sizes ranging from 0.89 to 4.85 mm. The ATR-FTIR spectral analyses revealed the presence of polymers polyethylene and Nylon 6. The occurrence of PP, Nylon 6, PET and PBT were confirmed using Raman spectroscopy. The presence of MPs in the gut content of alien fish P. brachypomus could be a reflection of the increasing microplastics pollution in the estuaries and backwaters along the south-west coast of India.

Oil spill risk assessments are important tools for the offshore oil and gas industries to minimize the consequences of deep spills. The stochastic modeling required in this kind of studies, is generally centered on surface transport and based on a Monte Carlo selection of hundreds or thousands of met-ocean scenarios from reanalysis databases, to create an ensemble of spill simulations. We propose a new integrated stochastic modeling methodology including both surface and subsurface transport, based on the specific selection of the most relevant environmental conditions through data-mining techniques. The methodology was applied to evaluate oil contamination probability as a consequence of a simulated deep release in the North Sea. Our results show the effectiveness of the proposed methodology to select representative evolutions of met-ocean conditions and to obtain pollution probabilities from an integrated subsurface and surface oil spill stochastic modeling, while assuring a manageable computational effort.

The effects of polystyrene (PS) of different sizes of diameter (65 nm, 100 nm and 1 μm) with different treat concentrations (control, 1 mg L⁻¹ and 10 mg L⁻¹) on growth and oxidative stress for K. mikimotoi were assessed across PS short-term exposures (3 d) and long-term exposures (13 d). The endpoints of physiological parameters such as cell density, antioxidant enzyme activity of SOD and CAT, the content of MDA and ROS level were monitored. The results showed that the CAT activity, SOD activity, MDA content and the relative ROS level reached to 377 U mgprot⁻¹, 164 U mgprot⁻¹, 157 nmol mgprot⁻¹ and 10.8% when treated with 10 mg L⁻¹ PS of 65 nm diameter; the CAT activity, SOD activity and MDA content in single K. mikimotoi reached to 0.46 U mgprot⁻¹, 0.36 U mgprot⁻¹ and 0.16 nmol mgprot⁻¹ under 10 mg L⁻¹ PS of 65 nm diameter on the third day. The relative ROS level in single K. mikimotoi was 71% under 10 mg L⁻¹ PS of 100 nm diameter on the 13th day. The works found that the size of nano/micro-PS was a key factor that cannot be ignored. Smaller size had more serious negative effects on the growth, oxidative stress and cell microstructure. The potential cytotoxicity mechanisms were that monodisperse nanoscaled PS crossed the biological barriers and the agglomerate nanoparticles caused physical blockage, while microscaled PS may not have such an equally strong negative effects. Visualized SEM images also proved that exposing to nano/micro-PS of varies diameters led to apparent size-dependent effects. The arms race of systematic oxidative defensive and offensive between K. mikimotoi and nano/micro-PS would have considerable value in deliberating the relationship between nano/microplastics and marine phytoplankton.

Sediment cores from Staten Island's salt marsh contain multiple historical oil spill events that impact ecological health. Microtox solid phase bioassay indicated moderate to high toxicity. Multiple spikes of TPH (6524 to 9586 mg/kg) and Σ16 PAH (15.5 to 18.9 mg/kg) were co-incident with known oil spills. A high TPH background of 400–700 mg/kg was attributed to diffuse sources. Depth-profiled metals Cu (1243 mg/kg), Zn (1814 mg/kg), Pb (1140 mg/kg), Ni (109 mg/kg), Hg (7 mg/kg), Cd 15 (mg/kg) exceeded sediment quality guidelines confirming adverse biological effects. Changes in Pb²⁰⁶/²⁰⁷ suggested three metal contaminant sources and diatom assemblages responded to two contamination events. Organic and metal contamination in Saw Mill Creek Marsh may harm sensitive biota, we recommend caution in the management of the 20–50 cm sediment interval because disturbance could lead to remobilisation of pre-existing legacy contamination into the waterway.

Species-level variability has made it difficult to determine the relative sensitivity of phytoplankton to oil and mixtures of oil and dispersant. Here we develop a phytoplankton group sensitivity index using ribosome sequence data that we apply to a mesocosm experiment in which a natural microbial community was exposed to oil and two oil-dispersant mixtures. The relative sensitivity of four phytoplankton taxonomic groups, diatoms, dinoflagellates, green algae, and Chrysophytes, was computed using the log of the ratio of the number of species that increase to the number that decrease in relative abundance in the treatment relative to the control. The index indicates that dinoflagellates are the most sensitive group to oil and oil-dispersant treatments while the Chrysophytes benefit under oil exposure compared to the other groups examined. The phytoplankton group sensitivity index can be generally applied to quantify and rank the relative sensitivity of diverse microbial groups to environmental conditions and pollutants.

We conducted experiments to investigate the effects of finfish aquaculture and to propose appropriate proxies for assessing their environmental impact. Due to enhanced fish feed input, sulfate reduction (SR) and the resulting metabolic products (H₂S, NH₄⁺, PO₄³⁻) were significantly greater at the farm than at the control site. Benthic release of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) from farm sediment accounted for 52–837% and 926–1048%, respectively, of the potential DIN and DIP demand for phytoplankton production. The results suggest that excess organic loading in fish farms induces deleterious eutrophication and algal blooms in coastal ecosystems via benthic-pelagic coupling. Direct SR measurement provided the most useful information of all the parameters on organic contamination in fish farms. However, given its abundance, relatively lower chemical reactivity and relative ease of analysis, elemental sulfur was regarded as the most appropriate proxy for assessing the environmental impacts of finfish aquaculture.

International audience | Plants were sampled from four different types of chlordecone-contaminated land in Guadeloupe (West Indies). The objective was to investigate the importance of biological and agri-environmental parameters in the ability of plants to bioaccumulate chlordecone. Among the plant traits studied, only the growth habit significantly affected chlordecone transfer, since prostrate plants concentrated more chlordecone than erect plants. In addition, intensification of land use has led to a significant increase in the amount of chlordecone absorbed by plants. The use of Bayesian networks uncovers some hypothesis and identifies paths for reflection and possible studies to identify and quantify relationships that explain our data.