To assess the effect of nutrient enrichment on the source and composition of sediment organic carbon (SOC) beneath Thalassia hemprichii and Enhalus acoroides in tropical seagrass beds, Xincun Bay, South China Sea, intertidal sediment, primary producers, and seawater samples were collected. No significant differences on sediment δ13C, SOC, and microbial biomass carbon (MBC) were observed between T. hemprichii and E. acoroides. SOC was mainly of autochthonous origin, while the contribution of seagrass to SOC was less than that of suspended particulate organic matter, macroalgae and epiphytes. High nutrient concentrations contributed substantially to SOC of seagrass, macroalgae, and epiphytes. The SOC, MBC, and MBC/SOC ratio in the nearest transect to fish farming were the highest. This suggested a more labile composition of SOC and shorter turnover times in higher nutrient regions. Therefore, the research indicates that nutrient enrichment could enhance plant-derived contributions to SOC and microbial use efficiency.

The metals cadmium, mercury and lead, and the ICES7 CB levels were analysed in the common dab Limanda limanda to investigate whether concentrations of these determinants are at levels above established OSPAR assessment criteria around England and Wales. The results indicate that CB118 is above the OSPAR derived EAC at 22 out of 29 sampled stations, with 15 showing significant reductions. Cadmium is increasing significantly at six stations with two sites in the North Sea breaching corresponding OSPAR EAC. Mean results for all other PCBs and metals stayed below the EAC thresholds, with Hg concentrations even falling below BAC levels at South Eddystone located in the western English Channel. This study shows that PCBs banned over 20years ago are still found at concentrations in fish liver tissues which may pose a health risk to both the individual fish and their predators.

An integrative biomarker approach was employed to evaluate the environmental quality of the north coast of Shandong Peninsula along the southern Bohai Sea of China, where pollution is an imminent threat due to rapid urbanization and industrialization. A battery of biomarkers and the metal bioaccumulation in tissues of native oyster Crassostrea gigas were measured under field conditions. Integrative biomarker index (IBR) and metal body burden were calculated to differentiate the pollution status of seven sampling sites. According to our results, Xinzhuang (XZ) site was the most severely contaminated, with the highest IBR value of 3.58, while the lowest IBR value (0.04) was obtained at Penglai (PL). Such an integrated biomarker approach was proved as a useful method for environmental quality assessment in the study area.

During two seasonal trawl surveys (April and October, 2012), red mullet specimens were caught from two sites of the northern Sicilian coast (Western Mediterranean), characterized by different degrees of pollution, to assess whether their digestive enzymes could be cost-effective diagnostic tools for endocrine disruption. Pepsin, chymotrypsin, carboxypeptidases A and B, amylase and lipase were measured in the digestive tract of each fish. During both samplings, significant differences in the digestive enzymatic patterns of fish collected from the two sites were found. In April, pepsin and lipase contents were significantly lower in fish from the most impacted site than in those from the reference site. In October, the enzymatic patterns showed trends different from spring, with controversial results for carboxypeptidases A and B and amylase. Pepsin and lipase patterns suggest a detrimental effect played by organic pollutants and the use of these enzymes as possible biomarkers of exposure to endocrine disruptors.

The accumulation of litter in marine and coastal environments is a major threat to marine life. Data on marine litter in the gastrointestinal tract of stranded loggerhead turtles, Caretta caretta, found along the Portuguese continental coast was presented. Out of the 95 analysed loggerheads, litter was present in 56 individuals (59.0%) and most had less than 10 litter items (76.8%) and less than 5g (dm) (96.8%). Plastic was the main litter category (frequency of occurrence=56.8%), while sheet (45.3%) was the most relevant plastic sub-category. There was no influence of loggerhead stranding season, cause of stranding or size on the amount of litter ingested (mean number and dry mass of litter items per turtle). The high ingested litter occurrence frequency in this study supports the use of the loggerhead turtle as a suitable tool to monitor marine litter trends, as required by the European Marine Strategy Framework Directive.

Development of desalination projects requires simple methodologies and tools for cost-effective and environmentally-sensitive management. Sentinel taxa and biotic indices are easily interpreted in the perspective of environment management. Echinoderms are potential sentinel taxon to gauge the impact produced by brine discharge and the BOPA index is considered an effective tool for monitoring different types of impact. Salinity increase due to desalination brine discharge was evaluated in terms of these two indicators. They reflected the environmental impact and recovery after implementation of a mitigation measure. Echinoderms disappeared at the station closest to the discharge during the years with highest salinity and then recovered their abundance after installation of a diffuser reduced the salinity increase. In the same period, BOPA responded due to the decrease in sensitive amphipods and the increase in tolerant polychaete families when salinities rose. Although salinity changes explained most of the observed variability in both indicators, other abiotic parameters were also significant in explaining this variability.

Bacterial quorum sensing signal molecules N-acyl homoserine lactones (AHLs) (C10-HSL, 3-OXO-C10-HSL and 3-OH-C10-HSL) as possible chemical cues were employed to investigate the role in the formation of fouling diatom-biofilm (Cylindrotheca sp.). Results showed that AHLs promoted Chlorophyll a (Chl.a) and extracellular polymeric substance (EPS) contents in the diatom-biofilm. In the presence of AHLs-inhibitor 3, 4-Dibromo-2(5)H-furanone, which was used to avoid the possible interference of AHLs from bacteria, AHLs also increased the Chl.a and EPS contents. Scanning electron microscope and confocal laser scanning microscope analysis further demonstrated that AHLs promoted the formation of the diatom-biofilm. Non-invasive micro-test technique showed that AHLs promoted Ca2+ efflux in Cylindrotheca sp., which implied that Ca2+ might be correlated with AHLs-induced positive effect on the formation of diatom-biofilm. This study provides direct evidences that AHLs play an important role in developing the diatom-biofilm and AHLs-inhibitors might be promising active agents in marine antifouling.

A bacterial consortium composed by four metagenomic clones and Bacillus subtilis strain CBMAI 707, all derived from petroleum reservoirs, was entrapped in chitosan beads and evaluated regarding hydrocarbon degradation capability. Experiments were carried out in mesocosm scale (3000L) with seawater artificially polluted with crude oil. At different time intervals, mesocosms were sampled and subjected to GC-FID and microbiological analyses, as total and heterotrophic culturable bacterial abundance (DAPI and CFU count), biological oxygen demand (BOD) and taxonomic diversity (massive sequencing of 16S rRNA genes). The results obtained showed that degradation of n-alkane hydrocarbons was similar between both treatments. However, aromatic compound degradation was more efficient in bioaugmentation treatment, with biodegradation percentages reaching up to 99% in 30days. Community dynamics was different between treatments and the consortium used in the bioaugmentation treatment contributed to a significant increase in aromatic hydrocarbon degradation.

In order to study element accumulation and trophic transfer in the food web, sixteen benthic invertebrate species and nine fish species were collected from the Daliao River estuary for analysis of toxic elements and nitrogen stable isotope in the muscle tissue. The concentrations ranged between 1.44–17.98, 0.01–9.30, 0.17–36.15, 0.7–145.4, 0.01–0.33, 0.14–14.88, 0.10–2.51, 0.02–0.14, and 19.3–221.1mgkg−1 for As, Cd, Cu, Hg, Ni, Pb, Sb, and Zn, respectively. As, Cd, Cu, and Zn were significantly higher in the benthic invertebrates than in fish, whereas Hg and Sb were significantly lower. In addition, the benthic invertebrates were characterized by the highest bioaccumulation factor (BAF) for Cd, whereas the fish were characterized by the highest BAF for Hg. A significant decrease in Cd, Cr, Cu, and Ni levels, and a significant increase in Hg and Sb levels were observed with increasing trophic levels.

Unusually large amounts of marine snow, including Extracellular Polymeric Substances (EPS), were formed during the 2010 Deepwater Horizon oil spill. The marine snow settled with oil and clay minerals as an oily sludge layer on the deep sea floor. This study tested the hypothesis that the unprecedented amount of chemical dispersants applied during high phytoplankton densities in the Gulf of Mexico induced high EPS formation. Two marine phytoplankton species (Dunaliella tertiolecta and Phaeodactylum tricornutum) produced EPS within days when exposed to the dispersant Corexit 9500. Phytoplankton-associated bacteria were shown to be responsible for the formation. The EPS consisted of proteins and to lesser extent polysaccharides. This study reveals an unexpected consequence of the presence of phytoplankton. This emphasizes the need to test the action of dispersants under realistic field conditions, which may seriously alter the fate of oil in the environment via increased marine snow formation.