During the Deepwater Horizon (DwH) oil spill, interactions between oil, clay particles and marine snow lead to the formation of aggregates. Interactions between these components play an important, but yet not well understood, role in biodegradation of oil in the ocean water. The aim of this study is to explore the effect of these interactions on biodegradation of oil in the water. Laboratory experiments were performed, analyzing respiration and n-alkane and BTEX biodegradation in multiple conditions containing Corexit, alginate particles as marine snow, and kaolin clay. Two oil degrading bacterial pure cultures were added, Pseudomonas putida F1 and Rhodococcus qingshengii TUHH-12. Results show that the presence of alginate particles enhances oil biodegradation. The presence of Corexit alone or in combination with alginate particles and/or kaolin clay, hampers oil biodegradation. Kaolin clay and Corexit have a synergistic effect in increasing BTEX concentrations in the water and cause delay in oil biodegradation.

Understanding how pollution affects populations is critical for targeted environmental risk assessments and adequate protection of the environment. However, the vast majority of ecotoxicology studies still have a traditional focus of identifying effects on individual organisms and do not measure the effects at the population-level. Modelling tools that measure population effects of pollution are available and would add value to current ecotoxicology studies by aligning outcomes more closely to what needs to be protected. In this paper I outline three possible reasons why this knowledge gap still exists and consider how they could be adopted more broadly, including better considerations about what endpoints should be measured at the initial study design phase. The purpose of highlighting this knowledge gap is to assist in facilitating the integration of population-level endpoints into routine pollution monitoring programs and progress of ecologically relevant ecotoxicology research.

We present worst-case assessments of contamination in sea ice and surface waters resulting from hypothetical well blowout oil spills at ten sites in the Arctic Ocean basin. Spill extents are estimated by considering Eulerian passive tracers in the surface ocean of the MITgcm (a hydrostatic, coupled ice-ocean model). Oil in sea ice, and contamination resulting from melting of oiled ice, is tracked using an offline Lagrangian scheme. Spills are initialized on November 1st 1980–2010 and tracked for one year. An average spill was transported 1100km and potentially affected 1.1 million km2. The direction and magnitude of simulated oil trajectories are consistent with known large-scale current and sea ice circulation patterns, and trajectories frequently cross international boundaries. The simulated trajectories of oil in sea ice match observed ice drift trajectories well. During the winter oil transport by drifting sea ice is more significant than transport with surface currents.

Bioelectrochemical systems (BESs) convert the energy present in wastewater to recover resources like bioelectricity, hydrogen, nutrients, heavy metals, minerals, and industrial chemicals. Various aspects of BES have been discussed here along with their applications and other advantages towards bioenergy recovery. More scientifically organized cross-discipline research efforts are required to scale-up these systems and to get benefit of recovering useful energy from waste materials. Full-scale implementation of bioelectrochemical wastewater treatment is complicated because certain microbiological, technological, and economic challenges need to be resolved that have not previously been encountered in any other wastewater treatment system. BES has higher prospects for in situ remediation of polluted water body or marshy soils and sediments. This technology is likely to evolve as a way of treating sewage, industrial, or agricultural wastewater, not only by lowering the amount of energy required, but at the same time producing electricity, hydrogen, or other chemicals of high value. Thus, after improving the performance of the BES, widening the scope for products recovery by developing better understanding of the process and with efforts to reduce its production cost, it can become a sustainable technology for treatment of wastewater with added advantage of recovery of resources and bioenergy.

The aim of this study was to evaluate the post-legislation change in tributyltin (TBT) pollution at Croatian Adriatic coast. Gastropod Hexaplex trunculus and sediments were collected, nearly 10years after TBT based antifouling paints were banned, at 12 locations along the coast where a previous study was conducted in 2005. The study showed a decline of TBT levels over the investigated period, although all gastropods populations were highly affected by imposex meaning that prohibition did not result in the recovery of populations. The further aim was to propose the Ecological Quality Ratio (EQR) boundaries for potential use of H. trunculus as a principal bioindicator in the assessment of the ecological status of the Mediterranean regarding TBT pollution, under the Water Framework Directive (WFD). According to the proposed EQR classes, the WFD target for achieving the Good ecological status of the marine environment by 2015 was not reached.

Our study aimed to evaluate crack cocaine effects in different life stages of the marine mussel Perna perna. For this purpose, fertilization rate, embryo-larval development, lysosomal membrane stability and DNA strand breaks were assessed. Effect concentrations in gametes and in larval development were found after 1h (IC50=23.53mg·L−1) and 48h (IC50=16.31mg·L−1), respectively. The highest tested concentration showing no acute toxicity (NOEC) was 10mg·L−1, while the lowest observed effect concentration (LOEC) was 20mg·L−1. NOEC concerning embryo-larval development was 0.625mg·L−1, while the LOEC was 1.25mg·L−1. Cyto-genotoxic effects were evidenced in mussels exposed to crack cocaine concentrations ranging from 5 to 500μg·L−1. Our results report the first data on effects of an illicit drug to marine organisms and should encourage further ecotoxicological studies of these contaminants of emerging concern in coastal ecosystems.

Between 2006 and 2013, we salvaged and necropsied 362 seabird specimens from Tern Island, French Frigate Shoals, Northwestern Hawaiian Islands. Plastic ingestion occurred in 11 of the 16 species sampled (68.75%), representing four orders, seven families, and five foraging guilds: four plunge-divers, two albatrosses, two nocturnal-foraging petrels, two tuna-birds, and one frigatebird. Moreover, we documented the first instance of ingestion in a previously unstudied species: the Brown Booby. Plastic prevalence (percent occurrence) ranged from 0% to 100%, with no significant differences across foraging guilds. However, occurrence was significantly higher in chicks versus adult conspecifics in the Black-footed Albatross, one of the three species where multiple age classes were sampled. While seabirds ingested a variety of plastic (foam, line, sheets), fragments were the most common and numerous type. In albatrosses and storm-petrels, the plastic occurrence in the two stomach chambers (the proventriculus and the ventriculus) was not significantly different.

The presence of fecal bacteria in seawater is one of the most important bio-indicator parameters of fecal pollution. In this study, the Bay of İzmir (in the eastern Aegean Sea), which is a critical area because of its relationship with marine transportation and industrial and commercial activities, was evaluated for its microbiological and physicochemical parameters through a monitoring program. The data were obtained from seasonally assembled surface seawater samples from 2015 to 2017 at 23 sampling stations. Bacteriological investigations were performed by membrane filtration technique. During the monitoring period, for stations at the inner and middle-outer part, it was found that the inner part is exposed to more number of fecal coliforms (8.8×102cfu/100mL) and fecal streptococci (1.1×103cfu/100mL). The monitoring analysis performed in this study showed that there was negative correlation between physicochemical parameters and the level of fecal bacteria, but no significance was recorded by the Pearson correlation test. Fecal contamination parameters should be routinely monitored for improving the environmental conditions of coastal cities.

Benthic surveys of mesophotic reefs in the Gulf of Mexico post Deepwater Horizon (DWH) showed that Swiftia exserta octocorals exhibited significantly more injury than in years before the spill. To determine the vulnerability of S. exserta to oil and dispersants, 96h toxicity assays of surrogate DWH oil water-accommodated fractions (WAF), Corexit® 9500 dispersant, and the combination of both (CEWAF) were conducted in the laboratory. Fragment mortality occurred within 48h for some fragments in the dispersant-alone and oil-dispersant treatments, while the WAF group remained relatively unaffected. The 96h LC50 values were 70.27mg/L for Corexit-alone and 41.04mg/L for Corexit in CEWAF. This study provides new information on octocoral sensitivity to toxins, and indicates that combinations of oil and dispersants are more toxic to octocorals than exposure to oil alone. These results have important implications for the assessment of effects of the DWH spill on deep-water organisms.

Heavy metals (Fe, Mn, Cr, Zn, Ni, Pb, Cu, Co and Cd) in the surface sediments of Cochin estuary, Southwest coast of India were analyzed to understand the spatio-temporal variation and contamination status via six sampling campaigns. Pollution indices like enrichment factor, geoaccumulation index and pollution load index inferred that the sediments of the northern arm of the estuary exhibited severe trace metal accumulation. Numerical sediment quality guidelines were applied to assess adverse biological effects of the trace metals, suggesting that occasional biological effect may occur due to Cr, Cu, Ni and Pb. Correlations between metals, organic carbon, silt and clay suggested that both fine grained sediment and organic matter were important carriers for these metals. Multivariate statistics indicated that the sources of Cu and Ni resulted primarily from natural weathering processes, whereas enriched levels of Cd, Cr, Zn and Pb were mainly attributed to anthropogenic activities.