A bloom of putatively non-indigenous species (NIS) Prorocentrum shikokuense was detected for the first time in the Mediterranean Sea at the Brindisi harbor (Southern Adriatic Sea) on September 2016, in the context of EU Marine Strategy Framework Directive monitoring in the ports. This species is usually observed in the East China Sea and Japanese and Korean waters. In the Brindisi harbor this dinoflagellate reached the concentration 105 cell/L and represented from 30 to 50% of the total phytoplankton population. Besides this event, Prorocentrum shikokuense has not been found blooming until today in Mediterranean waters. This study suggests the necessity to improve the monitoring surveys in areas that are known vulnerable systems to alien and invasive species, such as ports.

Dredging poses a potential threat to coral reefs, yet quantifying impacts is often difficult due to the large spatial footprint of potential effects and co-occurrence of other disturbances. Here we analyzed in situ monitoring data and remotely-sensed sediment plumes to assess impacts of the 2013–2015 Port of Miami dredging on corals and reef habitat. To control for contemporaneous bleaching and disease, we analyzed the spatial distribution of impacts in relation to the dredged channel. Areas closer to dredging experienced higher sediment trap accumulation, benthic sediment cover, coral burial, and coral mortality, and our spatial analyses indicate that >560,000 corals were killed within 0.5 km, with impacts likely extending over 5–10 km. The occurrence of sediment plumes explained ~60% of spatial variability in measured impacts, suggesting that remotely-sensed plumes, when properly calibrated against in situ monitoring data, can reliably estimate the magnitude and extent of dredging impacts.

Pot fisheries occur worldwide with a significant proportion of the gear becoming derelict. Derelict pots induce detrimental ecological and economic impacts, and more recently were found to reduce blue crab harvests in the Chesapeake Bay commercial fishery. We simulated the presence of derelict pots near actively fished pots in seasonal field experiments to quantify the effect derelict pots have on blue crab harvest. Derelict pots reduced harvests by 30% during the summer, but not during the fall. Female blue crab capture rates were consistently lower when derelict pots were present; while capture rates of the less abundant males were not negatively affected by derelict pots. Variable responses to derelict pots may be due to seasonal differences in female and male blue crab behavior and movements. The costly effect that derelict pots have on harvest should be investigated in other pot fisheries to recognize the magnitude and mechanisms behind these impacts.

Cadmium has had a number of historical applications in plastics but is now highly regulated. In this study, plastics containing pigmented or recycled Cd at concentrations up to 16,300 μg g⁻¹ were processed into microplastic-sized fragments and added to clean estuarine sediment. Plastic-sediment mixtures (mass ratio = 1:100) were subsequently exposed to fluids simulating the digestive conditions encountered in marine deposit-feeding invertebrates prepared from a protein and a bile acid surfactant in seawater and the mobilization of Cd measured as a function of time. Kinetic profiles over a six-hour period were complex, with some fitted using a diffusion model and others exhibiting evidence of Cd interactions between the plastic and sediment surface. The maximum concentration of Cd released from plastic-sediment mixtures was about 0.8 μg g⁻¹ and orders of magnitude greater than Cd mobilization from sediment alone. It is predicted that large communities of deposit-feeders could mobilize significant quantities of Cd from historical microplastics.

Plastic pollution is a pervasive problem to marine life. This study aimed (1) to investigate levels of microplastic in wild and farmed mussels (Perna perna), and (2) to assess the effectiveness of depuration in reducing microplastics. Wild and farmed mussels were sampled from Guanabara Bay (Southwestern Atlantic). Four treatments were compared (N = 10 mussels/treatment): wild non-depurated mussels, wild depurated mussels, farmed non-depurated mussels, and farmed depurated mussels. Up to 31.2 ± 17.8 microplastics/mussel (≥0.45 μm) were detected (means ± SD), and microplastics were present in all 40 individuals analyzed. Nylon fibers were more abundant than polymethyl methacrylate (PMMA) fragments. Blue, transparent, and red nylon fibers were more abundant in both wild and farmed mussels. Although 93 h-depuration significantly reduced microplastics (ANOVA, p = 0.02) in both wild (46.79%) and farmed mussels (28.95%), differences between farmed and wild mussels were not significant (p > 0.05). Depuration was more effective in removing blue fibers. Our results highlight the importance of depuration in reducing microplastic pollution in seafood.

Bacterial community is an important component of mangrove ecosystem and can participate in the cycling of elements and promote plant growth. However, the biogeographic distribution pattern of mangrove bacterial community and the associated factors remain poorly known. The present study explored the biogeographic distribution of sediment bacterial community in six mangroves across China. At each mangrove, sediments were collected from both Avicennia marina-planted zones and intertidal mudflats. The community abundance, richness, diversity and structure of sediment bacteria differed greatly among mangrove wetlands. Plantation showed a positive influence on sediment bacterial abundance, richness and diversity. Proteobacteria was the largest bacterial phylum in sediments. The biogeographic distribution of bacterial community in mangroves across China was driven by the variables associated with the wetland trophic status as well as other physicochemical factors (e.g., salinity).

The sorption of 5 Polyhalogenated carbazoles (PHCs) [3,6-dibromocarbazole (3,6-BCZ), 3,6-dichlorocarbazole (3,6-CCZ), 3,6-diiodocarbazole (3,6-ICZ), 2,7-dibromocarbazole (2,7-BCZ) and 3-bromocarbazole (3-BCZ)] on to three microplastics [polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC)] in a simulated seawater system are studied. Sorption isotherms demonstrated that PVC had the maximum sorption capacity, which can be attributed to polar-polar interaction. The sorption kinetics model showed that the sorption process was controlled by both intraparticle and film diffusion. The sorption of PHCs to microplastics was significantly influenced by temperature, the sorption capacity first increased gradually and then decreased with the increasing temperature. Increasing the salinity decreased the sorption of PHCs onto PP, PE, PVC microplastics. Our results indicated that all three kinds of microplastics can serve as carriers for PHCs in the aquatic environment, which put marine ecosystems at higher risks.

The Adriatic Sea, a semi-enclosed and vulnerable environment, deserves special attention regarding the risk of introducing Harmful Aquatic Organisms and Pathogens via ships' ballast water as new species findings occur at an alarming rate. This species introduction vector was addressed with the 2004 International Convention for the Control and Management of Ships' Ballast Water and Sediments, which entered into force in 2017. The efficient implementation of this convention calls for Adriatic States' cooperation on environmental specifics that have not been dealt with neither by national nor by international measures yet. Based on legal and institutional data gathered, and considering the regional maritime traffic and environmental specifics, this paper reveals that the integration of current environmental law commitments as well as a better dialogue between public institutions from shipping and environmental sectors may foster the implementation of ballast water management obligations through appropriate Adriatic States' cooperation.

Concentrations, spatial distribution and sources of aliphatic hydrocarbons (AH) and polycyclic aromatic hydrocarbons (PAH) were determined in surface seawater of the Gulf of Trieste, northern Adriatic. This area is one of the most industrialized and urbanized areas in the northern Adriatic with intense maritime traffic. The surface seawater samples were collected at 31 sites and total hydrocarbon concentrations were determined. In general, concentrations (0.1 to 43.2 μg l⁻¹, mean 4.8 μg l⁻¹, Chrysene equivalents) were higher in summer. Concentrations of total aliphatic hydrocarbons were from 17.2 to 2326.5 μg l⁻¹ (mean 543.3 μg l⁻¹). The major component was the unresolved complex mixture (UCM), comprising from 78% to 97% of the total aliphatic hydrocarbons. Total PAH concentrations varied from 89 ng l⁻¹ to 294 ng l⁻¹ (mean 179 ng l⁻¹). The most contaminated sites were the marina of San Giusto and the municipal harbor of Piran.Different evaluation indeces were applied to determine the origin of hydrocarbons. The prevailing origin of aliphatic hydrocarbons is petrogenic, with the significant contribution of the biogenic at some sites. The results presented indicate the fresh inputs of hydrocarbons, which are subject to intense degradation processes. The PAH group profile showed the predominance of 2–3 ring PAHs. PAHs were of mixed origin with more pronounced petrogenic origin, presumably due to oil spills from ships and boats. The presence of a relatively high content of perylene in seawater is an indication of its terrestrial input.According to the presented results and compared to results from different areas worldwide, the seawater in the Gulf of Trieste can still be considered slightly to moderately polluted with PAHs.

Glassfish, Ambassis dussumieri (Cuvier, 1828), was used as a sentinel species to investigate the effects of the ingestion of environmentally relevant microplastic concentrations on juvenile fish growth and survival. Both virgin plastic and plastic collected from an urban harbour were fed to small juvenile fish daily for 95 days. Fish standard length, body depth and mass were recorded at intervals of 20 days, while survival was continuously recorded. All fish were fed tropical flakes, measured at 1.7% of the body mass per tank. Overall, fish in in plastic treatments grew less in body length and body depth compared to those control treatments. Fish mass was also lower in the virgin plastic treatment than control fish; however, the growth in mass was not significantly lower than fish in the harbour plastic treatment. The survival probability of fish in both plastic fed treatments was also lower than fish in controls.