The seasonal shift in the homogeneity of the periphytic protozoan fauna was studied based on a four-season baseline survey in the coastal waters of the Yellow Sea, northern China. Samples were collected using glass microscope slides as an artificial substratum at a depth of 2 m after the immersion time of 14 days during each of the four seasons (winter, spring, summer, and autumn, 2017). The protozoan fauna showed a clear seasonal shift in species composition and a significant variation in homogeneity in terms of both compositional and community structure during four seasons. The dispersion measures and β-diversity index represented an increase in the trend from spring to winter. These findings suggest that the homogeneity of the periphytic protozoan fauna was subject to a significant variability shaped mainly by species composition during a four-season cycle in marine ecosystems.

Ocean acidification (OA) can induce changes in marine organisms and species interactions. We examined OA effects on intertidal macroalgal growth, palatability, and consumption by a specialist crab (Pugettia producta) and a generalist snail (Tegula funebralis) herbivore. Moderate increases in pCO₂ increased algal growth in most species, but effects of pCO₂ on C:N and phenolic content varied by species. Elevated pCO₂ had no effect on algal acceptability to herbivores, but did affect their preference ranks. Under elevated pCO₂, electivity for a preferred kelp (Egregia menziesii) and preference rankings among algal species strengthened for both P. producta and T. funebralis, attributable to resilience of E. menziesii in elevated pCO₂ and to changes in palatability among less-preferred species. Preferred algae may therefore grow more under moderate pCO₂ increases in the future, but their appeal to herbivores may be strengthened by associated shifts in nutritional quality and defensive compounds in other species.

To address knowledge gaps and the lack of benchmarks on the toxicity of dilbit oiled sediments, weathered Cold Lake Blend (CLB) and Western Canadian Select (WCS) were assessed in 10-day sediment tests with the amphipods Hyalella azteca and Leptocheirus plumulosus. Lowest observed effect concentrations (LOECs) and 20% effect levels (EC20s) were determined for wet weight sediment concentrations of TPH and total PAHs normalized to 1% organic carbon. LOECs and EC20s for TPH ranged from 216 to 1165 mg/kg sediment in H. azteca, and from 64 to 75 mg/kg sediment in L. plumulosus. Dilbit LOECs and EC20s for total PAHs ranged from 2.9 to 11.8 mg/kg sediment in H. azteca, and from 0.75 to 0.87 mg/kg in L. plumulosus. Comparison of toxicity-based benchmarks derived from the current study to sediment concentrations from past spills indicate that dilbit spills in aquatic habitats may pose substantial risks to freshwater and estuarine benthic organisms.

Microplastics (MPs) patterns in a weakly-stratified estuary were investigated using a combined approach of observations and modeling. The study was conducted in the Guadalquivir River Estuary, which is of high environmental value, yet significantly altered by human activities. The study aims to contribute to understanding and quantifying the land-ocean transport of MPs. Mean concentrations of MPs in the estuary were 0.041itemsm⁻³, with maximum values up to 0.20itemsm⁻³, in agreement with the range reported in other estuaries. Polyethylene floating MPs were predominant. Relationships between increases in MP concentration and local rainfall events were identified in the middle estuary when there were no significant discharges from the head dam. Modeling results mimicked observations and revealed the effects of tidal straining, density-driven, and river flow-induced circulation on the net transport. Convergence of transports favors the MPs trapping in the vicinity of Doñana National Park, overlapping the location of the Estuarine Turbidity Maximum.

The coastal pollution has been evaluated using indexes like Clean Coast Index (CCI) in many countries. In this study, several coasts and urban areas in northern of Iran along the Caspian Sea, were assessed in terms of number and composition of litters. Furthermore, Clean Environment Index (CEI) was used for the first time to interpret the results. The results indicated that 60% of the coasts and 50% of the urban areas were in a dirty status and only 22% of the total surveyed areas were found to be in a clean status. The highest number of litters observed in the study areas was cigarette butt. Due to the impact of risk factor of different types of littered waste, it was obviously clear that CEI offers a more realistic and rigorous interpretation than CCI. Therefore, this new index can be considered to evaluate litters pollution in various areas.

This study aimed to investigate the toxicity of innovative antifouling nanostructured biocides DCOIT and silver associated to silica nanocapsules (SiNC) on the tropical microcrustacean Mysidopsis juniae. The toxicity of the tested compounds can be summarized as follows (acute tests): DCOIT > SiNC-Ag > SiNC-DCOIT > SiNC-DCOIT-Ag > SiNC > Ag; (chronic tests): SiNC-Ag > SiNC-DCOIT-Ag > DCOIT > Ag > SiNC, although it was not possible to determine the chronic toxicity of SiNC-DCOIT. In general, our data demonstrated that mysids were more sensitive than most temperate species, and it was possible to conclude that the combination SiNC-DCOIT-Ag showed less acute toxicity in comparison to the isolated active compounds, reinforcing data obtained for species from temperate environments on the potential use of nanomaterial to reduce toxicity to non-target species. However, despite representing less risk to the environment, the compound SiNC-DCOIT-Ag is still very toxic to the non-target tropical mysid.

PURPOSE OF REVIEW: This review is focused on the removal of chlorinated hydrocarbons (as representative of persistent pollutants) from soil by soil-washing techniques, paying special attention to the application of electrochemically assisted technologies for the treatment of the liquids and gases produced during this treatment. It considers the degree of maturity of the technologies and suggests challenges for future research. RECENT FINDINGS: Electrochemical technologies can help to improve the overall efficiency of soil washing processes in the removal of chlorinated hydrocarbons, contributing to the depletion of these hazardous species from the soil washing liquid and gaseous effluents generated during the treatment of the soil. Chlorinated hydrocarbons are a good example of persistent organic pollutants which can be found in very high concentrations in polluted soil, especially in industrial sites. Because of its fast action, soil washing can be efficient for preventing the spread of chlorinated hydrocarbons after accidental spills. Recent progress about fundamentals of this process and key parameters involved is discussed at the light of competing technologies, paying special attention to the liquid and gaseous wastes produced during this treatment, in the search of holistic approaches. Among the different alternatives proposed, electrochemical technologies are the focus of attention of many researchers and, because of that, recent progress in electrochemical technologies capable to deplete the pollutants is also discussed, within a comparison context with other competing technologies, indicating the technology readiness level of each electrochemical process and the challenges that must be overcome in order to reach full-scale applicability.

Macrocystis pyrifera reaches distant areas after detachment, accumulate heavy metals, and serve as trophic subsidy. In this context, effects on both adults and larvae of Tetrapygus niger fed with polluted kelps were determined by assessing growth, fertility, and early larval development. Results revealed that sea urchins fed with polluted kelps from highly impacted zone (HIZ) showed a lower growth (3.6% gained weight) and gamete release (358 cells mL⁻¹) than those fed with non-impacted kelps (NIZ) (19.3% and 945 cells mL⁻¹). The HIZ treatment showed a developmental delay in comparison to NIZ, accounted mainly by the abundance of malformed 2-arm pluteus larvae (10–15%) during most of the culture. Malformed 4-arm pluteus larvae showed a constant increase, reaching 37% at the end of the culture. Thus, the pollutants ingested by sea urchins can be transferred to their offspring and cause negative effects in their early development, categorizing M. pyrifera as a pollutant carrier.

Controversy remains on the use of Sub-Sea Dispersant Injection (SSDI) during the Deepwater Horizon (DWH) spill to minimize the exposure of responders on surface vessels to volatile organic compounds (VOC). Here, we use extensive evidence (>90,000 VOC measurements) collected near the oil well MC252 site during the DWH spill and demonstrate at a high level of statistical confidence that SSDI enhanced the safety and health conditions of the responders at the water surface through the reduction of airborne VOC concentrations in a dose-dependent manner. VOC levels on ships' decks were clearly diminished (p < 0.001) during subsea dispersant use, and incidents of peak concentrations (>50 ppm VOC) that could have been an immediate concern to worker health were reduced by a factor of ~6 to 19 when dispersants were delivered at the intended rate. SSDI thus played an important role in minimizing potential exposure to VOC, and should be embedded in guidelines and regulations for dispersant use.

Despite exponential growth of anthropogenic marine debris in recent decades, plastic ingestion by marine turtles in the Gulf of Mexico is not well understood. Gastrointestinal tracts were examined from 464 green turtles that stranded in Texas between 1987 and 2019, and 226 turtles ingested plastic (48.7%). This number doubled from 32.5% in 1987–1999 to 65.5% in 2019, but mass of ingested items was lowest in 2019. No turtles showed evidence of death directly related to plastic ingestion. Compared to other regions, plastic ingestion was low. Small turtles (<25 cm straight carapace length) ingested plastic more frequently and in greater amounts than larger turtles. Small turtles also ingested more hard plastic while larger turtles ingested more sheet-like and thread-like plastics, which may correspond to size-based habitat shifts. This is among the largest marine turtle ingestion studies to date and demonstrates an increasing prevalence of plastic ingestion.