Mechanical interventions are increasingly suggested as a means of removing plastic litter from aquatic environments; their performance is rarely evaluated, but such information is critical to inform policy interventions such as those required to facilitate UNEA 5.2. The Seabin, a fixed-point device designed to remove floating litter in sheltered waters was examined in an urban tidal marina (Southwest UK). It captured on average 58 litter items/day; chiefly plastic pellets, polystyrene balls and plastic fragments. It also captured one marine organism for every 3.6 items of litter, or 13 organisms/day, half of which were dead upon retrieval. The rate of litter capture was inferior to manual cleaning conducted with nets from pontoons or vessels. Hence, in this location the Seabin was of minimal benefit in terms of marine litter removal and resulted in mortality of marine organisms. The presence of such devices could also precipitate false optimism and reliance on technological solutions, rather than systemic changes in our production, use, and disposal of plastics.

This is the first study to analyze the whole-genome sequence of B. manjavacas Australian (Aus.) strain through combination of Oxford Nanopore long-read seq, resulting in a total length of 108.1 Mb and 75 contigs. Genome-wide detoxification related gene families in B. manjavacas Aus. strain were comparatively analyzed with those previously identified in other Brachionus spp., including B. manjavacas German (Ger.) strain. Most of the subfamilies in detoxification related families (CYPs, GSTs, and ABCs) were highly conserved and confirmed orthologous relationship with Brachionus spp., and with accumulation of genome data, clear differences between genomic repertoires were demonstrated the marine and the freshwater species. Furthermore, strain-specific genetic variations were present between the Aus. and Ger. strains of B. manjavacas. This whole-genome analysis provides in-depth review on the genomic structural differences for detoxification-related gene families and further provides useful information for comparative ecotoxicological studies and evolution of detoxification mechanisms in Brachionus spp.

A novel adsorbent, 3-phenyl-1-(2-pyridyl)thiourea (PPTU) was synthesized and its adsorption capabilities were studied for Cu(II), Cd(II), Ni(II), Pb(II) and Fe(II) cations in the waters such as tap and polluted seawaters. The kinetics, Langmuir and Freundlich isotherms were discussed related to the adsorptions. The adsorption capacities of PPTU were found 9.4; 12.6; 90.9; 57.1 and 30.4 mg g⁻¹ and preconcentration with PPTU including the FAAS step yielded the LOQ values 0.46; 2.65; 1.12; 2.65 and 1.72 ng mL⁻¹ for Cu(II), Cd(II), Ni(II), Pb(II) and Fe(II), respectively. The adsorbent after the elutions and washings could be reused three times in the next adsorptions. The interferences on the adsorptions arising from the major cations of the seawater and the usability of PPTU for interested metals in the seawater were discussed. The proposed method is simple with highly efficient and green preconcentration procedure for trace analysis of the target metal ions.

In this study, the physiology of symbiotic ‘peacock-tail’ shrimp Ancylocaris brevicarpalis and its host ‘Haddon's carpet’ sea anemone Stichodactyla haddoni were tested under lowered pH (7.7) and control (8.1) conditions. The biochemical responses such as digestive enzyme (AP), organic acids (lactate and succinate), oxidative damages (MDA), antioxidants metabolites/enzymes (ASC, GSH, SOD, CAT, APX, GPX, GR, POX, and PHOX), and detoxification enzyme (GST) were measured. The AP showed insignificantly reduced values in both the organisms in lowered pH conditions compared to control indicating the effect of abiotic stress. The hierarchical clustering analysis indicated low MDA in sea anemone can be explained by higher POX, APX, GR, ASC, and GSH levels compared to shrimps. However, the detoxification enzyme GST showed less activity in sea anemones compared to shrimps. The results suggest that A. brevicarpalis and sea anemone S. haddoni may have deleterious effects when exposed to short-term acidification stress.

This study aimed to assess the maternal offloading of metals in the Brazilian guitarfishPseudobatos horkelii through determining essential (Cr, Cu, Fe) and non-essential (Cd, Hg, Pb) metal concentrations along two generations of this species: pregnant females and offspring. The maximum transfer capacity (ECER) and offspring/mother ratio were calculated to estimate the extent of offloading, as well as the proportion of contaminants presented in offspring related to the maternal concentrations. Transfer efficiency was element-dependent. Chromium had the highest ECER (99.7%), followed by Hg (67.7%). Other essential metals were less transferred (9.6–35.6%) and Cd and Pb were not detected in uterine content samples. The relationships between maternal length and concentration, as well as transfer capacity were not significant, indicating that females might be continuously exposed, and that offloading might not excrete metals efficiently. On the other hand, embryos are exposed to these elements which could impair embryonic development.

Investigations of the physicochemical degradation of personal protective equipment (PPE) under controlled environmental conditions are largely lacking. Here the chemical and physical changes of face masks and gloves (recovered from the marine environment) were evaluated after exposure time up to 60 days of simulated environmental conditions. The results suggested that the polymer backbone of PPE suffers typical changes induced by sun exposure. Changes in the intensity of diffraction peaks indicated shifts in the crystallinity of PPE, possibly altering their thermal behavior. Signs of physical degradation in PPE, such as ruptures, and rough surfaces, which exacerbated over time were also detected. Additionally, signals of some elements of concern, such as Cu and Mo, and elements typically found in seawater were detected. The results of this study allowed us to better understand the degradation of typical PPE items in the marine environment, ultimately resulting in the release of microplastics and chemical contaminants.

The increasing level of marine plastic pollution poses severe threats to the marine ecosystem and biodiversity. Open remote sensing data and advanced machine learning (ML) algorithms could be a cost-effective solution for identifying large plastic patches across the scale. The potential application of such resources in detecting and discriminating marine floating plastics (MFP) are not fully explored. Therefore, the present study attempted to explore the full functionality of open Sentinel satellite data and ML models for detecting and classifying the MFP in Mytilene (Greece), Limassol (Cyprus), Skala Loutron, Greece, Calabria (Italy), and Beirut (Lebanon). Two ML models, i.e. Support Vector Machine (SVM) and Random Forest (RF), were utilized to perform the classification analysis. In-situ plastic location data was collected from the control experiments conducted in Mytilene, Greece (in 2018 and 2019), Skala Loutron, Greece (2021), and Limassol, Cyprus (2018), and the same was considered for training the models. The accuracy and performances of the trained models were further tested on unseen new data collected from Calabria, Italy and Beirut, Lebanon. Both remote sensing bands and spectral indices were used for developing the ML models. A spectral signature profile for marine plastic was created for discriminating the floating plastic from other marine debris. A newly developed index, kernel Normalized Difference Vegetation Index (kNDVI), was incorporated into the modelling to examine its contribution to model performances. Both SVM and RF were performed well in five models and test case combinations. Among the two ML models, the highest performance was measured for the RF. The inclusion of kNDVI was found effective and increased the model performances, reflected by high balanced accuracy measured for model 2 (~89% to ~100% for SVM and ~92% to ~98% for RF). An automated floating plastic detection system was developed and tested in Calabria and Beirut using the best-performed model. The trained model had detected the floating plastic for both sites with ~80%–90%% accuracy. Among the six predictors, the Floating Debris Index (FDI) was the most important variable for detecting marine floating plastic. These findings collectively suggest that high-resolution remote sensing imagery and the automated ML models can be an effective alternative for the cost-effective detection of MFP. Future research will be directed toward collecting quality training data to develop robust automated models and prepare a spectral library for different plastic objects for discriminating plastic from other marine floating debris and advancing the marine plastic pollution research by taking full advantage of open-source data and technologies.

This paper analyzed the long-term variations in nutrients in Liaodong Bay and their potential influencing factors based on historical data from 1978 to 2019. Under the influence of both human activities and natural changes, the concentration of DIN increased approximately 4-fold from the end of the 1990s to the mid-2010s, while DIP and DSi concentrations decreased from the beginning to the end of the 1980s and have since increased again. Asynchronous changes in nutrient levels have led to changes in the nutrient composition, which has caused a series of ecological effects. The total phytoplankton abundance decreased from the 1980s to the end of the 1990s and then increased again. Additionally, the phytoplankton composition shifted from a diatom-dominated to a dinoflagellate-dominated system, and the dominant species of zooplankton changed. Harmful algal blooms (HABs) rarely occurred before the 1980s but have frequently occurred since the end of the 1990s.

Coastal plastic pollution is a global problem, it affects local ecosystems, and can have economic and social implications. Plastic pollution is pervasive at high latitudes but there is a lack of data on the spatial and temporal amount of marine litter entering coastal systems. In this study, a seasonal accumulation survey of anthropogenic debris and beach wrack was conducted for the first time in Iceland. One hundred data collections were performed on a coast in the Snæfellsnes peninsula throughout one year. Of all the debris retrieved, over 9000 items (0.2 to 50 cm), 78.5 % were plastics. Beach wrack correlated strongly with the quantities of plastic debris entering the coastal environment (R² > 0.9; p < 10⁻¹¹), with a different slope for each season. The presence of beach wrack informed important daily and spatial fluctuations in the quantities of plastic debris, while seasonal fluctuations demonstrated higher arrival rate of plastic in autumn and winter.

Knowledge of the status of the black-lipped pearl oyster Pinctada margaritifera populations is critical for the sustainability of the French Polynesia black pearl farming industry. Indeed, this activity relies on collection of spat settling out of the water column, which is inherently related to the abundance of in situ benthic stocks and their reproductive capacities. From surveys performed between 2016 and 2021, we present new stock assessments of natural wild oyster populations from four contrasted pearl farming lagoons (Gambier, Takapoto, Raroia, Takume). Also using Ahe atoll historical data, we first highlight how results vary with the methods (Direct, Zonal and Cokriging) used to scale in situ density measurements to lagoon-scale stocks. Takapoto and Gambier populations were also previously surveyed at least twice since the 1980s, allowing to demonstrate with field data clear changes in stock distributions and population structures. The consequences of our findings are discussed to provide recommendations for stock monitoring and management in the future.