There is significant risk associated with increased oil and gas exploration activities in the Arctic Ocean. This paper presents a probabilistic methodology for Ecological Risk Assessment (ERA) of accidental oil spills in this region. A fugacity approach is adopted to model the fate and transport of released oil, taking into account the uncertainty of input variables. This assists in predicting the 95th percentile Predicted Exposure Concentration (PEC95%) of pollutants in different media. The 5th percentile Predicted No Effect Concentration (PNEC5%) is obtained from toxicity data for 19 species. A model based on Dynamic Bayesian Network (DBN) is developed to assess the ecological risk posed to the aquatic community. The model enables accounting for the occurrence likelihood of input parameters, as well as analyzing the time-variable risk profile caused by seasonal changes. It is observed through the results that previous probabilistic methods developed for ERA can be overestimating the risk level.

Marine litter is a major source of pollution in the Mediterranean basin, but despite legislative requirements, scant information is available for the ongoing assessment of this threat.Using higher size classes as proxy for litter distribution, this study gave a synoptic estimation of the amount, composition, and distribution of floating macro-litter in the Mediterranean. The average amount of macro-litter was in a range of 2–5items/km2, with the highest in the Adriatic basin. Seasonal patterns were present in almost all study areas and were significant in the Ligurian Sea, Sardinian-Balearic basin, and Central Tyrrhenian Sea. Plastic accounted for >80% of litter in all areas and seasons, with the highest proportion in the Adriatic Sea, Ligurian Sea, and Sicilian-Sardinian Channels; in the Bonifacio Strait, Tyrrhenian Sea, and Sardinian-Balearic basin, litter composition was instead more diverse. Spatial analysis suggested an almost homogeneous distribution of litter without evident regular aggregation zones.

Small fringing marshes are ecologically important habitats often impacted by petroleum. We characterized the phylogenetic structure (16S rRNA) and petroleum hydrocarbon degrading alkane hydroxylase genes (alkB and CYP 153A1) in a sediment microbial community from a New Hampshire fringing marsh, using alkane-exposed dilution cultures to enrich for petroleum degrading bacteria. 16S rRNA and alkB analysis demonstrated that the initial sediment community was dominated by Betaproteobacteria (mainly Comamonadaceae) and Gammaproteobacteria (mainly Pseudomonas), while CYP 153A1 sequences predominantly matched Rhizobiales. 24 h of exposure to n-hexane, gasoline, dodecane, or dilution culture alone reduced functional and phylogenetic diversity, enriching for Gammaproteobacteria, especially Pseudomonas. Gammaproteobacteria continued to dominate for 10 days in the n-hexane and no alkane exposed samples, while dodecane and gasoline exposure selected for gram-positive bacteria. The data demonstrate that small fringing marshes in New England harbor petroleum-degrading bacteria, suggesting that petroleum degradation may be an important fringing marsh ecosystem function.

In this study, we used high-throughput sequencing of 16S rRNA gene amplicons, to investigate the spatio-temporal variation in bacterial communities in surface-waters collected from eight major outlets of the Pearl River Estuary, South China. Betaproteobacteria were the most abundant class among the communities, followed by Gammaproteobacteria, Alphaproteobacteria, Actinobacteria, and Acidimicrobiia. Generally, alpha-diversity increased in winter communities and the taxonomic diversity of bacterial communities differed with seasonal and spatial differences. Temperature, conductivity, salinity, pH and nutrients were the crucial environmental factors associated with shifts in the bacterial community composition. Furthermore, inferred community functions that were associated with amino acid, carbohydrate and energy metabolisms were lower in winter, whereas the relative abundance of inferred functions associated with membrane transport, bacterial motility proteins, and xenobiotics biodegradation and metabolism, were enriched in winter. These results provide new insights into the dynamics of bacterial communities within estuarine ecosystems.

Macro- and microplastics abundances were determined in the Adriatic Sea following the MSFD TG10 protocol. The studied areas included populated gulfs, river outlets and offshore waters in five Adriatic countries. The use of small ships enabled us to detect small sized plastics (2.5–5 cm) and record average macroplastics densities of 251 ± 601 items km−2, one order of magnitude higher than previously considered. Results from manta net tows for microplastics revealed an average abundance of 315,009 ± 568,578 items km−2 (217 ± 575 g km−2). We found significantly higher microplastics abundances in nearshore (≤4 km) than in offshore waters (>4 km) and this trend seems to affect also the small sized macro plastic fragments (2.5–5 cm). The dominant polymers were polyethylene and polypropylene while the presence of some rare polymers and waxes used in food and dentistry indicated waste water treatment plants as potential sources of microplastics.

The impact that microplastics (<5 mm) have on scleractinian coral is largely unknown. This study investigated calcification effects, size limits, and retention times of microbeads and microfibers in two Caribbean species, Montastraea cavernosa and Orbicella faveolata, in a series of three experiments. No calcification effects were seen in the two-day exposure to a microbead concentration of 30 mg L−1. M. cavernosa and O. faveolata actively ingested microbeads ranging in size from 425 μm–2.8 mm, however, a 212–250 μm size class did not elicit a feeding response. The majority of microbeads were expelled within 48 h of ingestion. There was no difference in ingestion or retention times of 425–500 μm microbeads versus 3–5 mm long microfibers. M. cavernosa and O. faveolata have the ability to recognize and reject indigestible material, yet, there is still a need to study effects of energetics and microplastic contamination as a result of ingestion and egestion.

While the California spiny lobster (Panulirus interruptus) is an important commercial and recreational fishery species in California, there is a lack of data on bioaccumulation for the species. This study examined pollutant tissue concentrations in lobsters from San Diego Bay, California. Observed lobster pollutant tissue concentrations in tail muscle were compared to State of California pollutant advisory levels. Concentrations were then used to conduct risk assessment using catch data from the California Department of Fish and Wildlife.Study results found little bioaccumulation of organic pollutants in tail tissue, likely due to low observed lipids. Mercury was present, predominantly in methyl form, at concentrations above advisory levels. Recreational catch data for San Diego Bay showed increased non-cancer risk for fishers at the 90th percentile or greater of reported annual catch. Further studies should focus on non-tail tissues, as exploratory whole lobster samples (n = 2) showed elevated organic pollutants and metals.

Microplastics are ubiquitous contaminants that could harm ecosystems. Wastewater contains microplastics and may lead to further contamination of the environment. This focus article presents a summary of current knowledge on microplastics in wastewater and possible solutions, suggesting current research needs.

Abundance and spatial distribution of benthic foraminifera were used to evaluate the impacts of anthropogenic activities on sediment quality in a coastal lagoon in the Gulf of California. In 1985 and 2013, 27 samples of superficial sediments were collected. The foraminifera genera Ammonia, Cribroelphidium, Quinqueloculina and Peneroplis were dominant in both years. The abundance of Ammonia increased from 41% to 60%, while Peneroplis abundance decreased from a maximum of 50% in 1985 to 7% in 2013. The greater abundance of Ammonia and the greater spatial coverage of Ammonia and Cribroelphidium suggest a marked environmental deterioration in the quality of the sedimentary environment, which contrasts with studies of trace elements in the sediment of this lagoon. The Foram Stress Index indicates that sediment quality has deteriorated over time, likely due to the effects of anthropogenic activities around the lagoon.

To extent the understanding on microplastics in the marine environment we performed a case study at four beaches on the Isle of Rügen considering abundance and spatial distribution of microplastics in beach sediments. For the analysis, density separation via a glass elutriation column was implemented. In advance, efficiencies were tested for two polymers, being not buoyant in water. Recovery rates of 80% for PET and 72% for PVC particles in sandy samples were achieved.A median abundance of 88.10 (Q1=55.01/Q3=114.72) microplastic particles per kg dry sediment or 2862.56 (Q1=1787.34/Q3=3727.28) particles per m2 was found at the beaches on Rügen. Fibers were more abundant than fragments at all beaches. In this study, no statistically significant differences but only tendencies were determined between the beaches with different exposition and anthropogenic activity as well as for distribution patterns which showed that microplastic fragments accumulate in topographic depressions, similar to macrolitter items.