Concentrations and enrichment of major (Na, Al and Cl) and trace (V, Mn, Fe, Ni, Cu, Zn, As, Br, Mo, Hg, Pb and U) elements were evaluated in ²¹⁰Pb-dated sediment cores from saltmarsh areas surrounding an anthropized lagoon at southeastern Gulf of California. A chemometric approach was used to identify the sedimentary processes that control the variability of elements among the cores; and the elemental fluxes were compared among coring sites on the basis of historical urbanization and industrial development in the area. The highest fluxes and excess concentrations of V, Ni, Hg and Pb were observed after 1960 in cores EUI and EUIII, and in 1980 at EUII. In general, the historical trends of metal enrichment coincide with the growth of urban and industrial developments around the lagoon, and particularly with the beginning and full operation of a thermoelectric power plant in 1980s.

Trophodynamics and risks of polychlorinated biphenyls (PCBs) in organisms from the Zhoushan fishing ground (ZFG), China were studied. Σ₂₂PCBs varied from 1.36 to 36.75 ng/g wet weight, which were far below the maximum residue levels allowed in fishery products. However, estimated daily intake and hazard ratio calculations present possible adverse effects due to PCB pollution. Significantly positive correlations appeared between wet-weighted concentrations of target chemicals and trophic levels (TLs) of the organisms, with trophic magnification factors (TMFs) from 1.15 to 9.72. The TMF values first increased with an increase of compound's KOW values, and then decreased, with log KOW around 7.0 as an inflection point. TL is suggested as the key factor controlling contaminant burden among the species for only PCBs 105, 138, 153, and 171. For the remaining PCBs, lipid content of the organism or metabolite capacity of the compound may be more important influence on their bioaccumulation.

Vibrio species are widely distributed in the estuarine and coastal waters that possess the greatest threat to human health worldwide. In this study it is aimed to isolate and observe the abundance of Vibrio sp. and prevalence of biomarker genes and antibiotic resistance profile of V. cholerae isolated from the Port Blair bays of South Andaman. A total of 56 water samples were collected from the seven sampling stations of Port Blair bays in which maximum number of Vibrio sp. population density (1.78 × 10⁴) was recorded in Phoenix Bay. Among the 786 isolates 57.38% of the isolates were confirmed as Vibrio sp., Vibrio cholerae and Vibrio parahaemolyticus. PCR results revealed that the prevalence of biomarker genes was recorded maximum in the isolates from Phoenix Bay and Junglighat Bay samples. Upon further analysis, it was observed that the prevalence of hlyA gene (215 bp), was found to be the most widespread biomarker determinant in 84.17% of isolates. Major virulence determinants; ctxA, ompU and toxR genes were not detected in V. cholerae isolates from Port Blair bays. Maximum antibiotic resistance pattern was observed in Phoenix Bay isolates and maximum number of V. cholerae isolates was resistance to tetracycline (60.76%). Cluster and Principal Component Analysis were employed to understand the diversity and distribution of Vibrio isolates and its biomarker genes. Upon PCA analysis seasonal influence was not much perceived in Vibrio species diversity in Port Blair bays and the lack of significant difference in the detection of species diversity in this study is due to resemblance in geographical conditions and sources of pollution.

As small pieces of plastics known as microplastics pollute even the remotest parts of Earth, research currently focuses on unveiling how this pollution may affect biota. Despite increasing awareness, one potentially major consequence of chronic exposure to microplastics has been largely neglected: the impact of the disruption of the symbiosis between host and the natural community and abundance pattern of the gut microbiota. This so-called dysbiosis might be caused by the consumption of microplastics, associated mechanical disruption within the gastrointestinal tract, the ingestion of foreign and potentially pathogenic bacteria, as well as chemicals, which make-up or adhere to microplastics. Dysbiosis may interfere with the host immune system and trigger the onset of (chronic) diseases, promote pathogenic infections, and alter the gene capacity and expression of gut microbiota. We summarize how chronically exposed species may suffer from microplastics-induced gut dysbiosis, deteriorating host health, and highlight corresponding future directions of research.

The concentrations of some trace metals in the Acropora downingi coral skeleton and sediment samples of Khark Island, Chirouyeh and Hendorabi Island in the northern part of the Persian Gulf were evaluated to determine the ecological risks of trace metal contamination in the sediment. Risk assessment indices revealed that Cd in all of the studied areas as well as Ni and Pb in Chirouyeh site would be expected to cause ecological risk occasionally. Moreover, Chirouyeh site showed a high tendency for trace metal adsorption. Khark and Chirouyeh sites showed higher risk values than the unpopulated Hendorabi, indicating that the anthropogenic activities had a significant impact on the trace metal contamination. Multivariate clustering dendrogram and Pearson's correlation coefficient indicated that Pb originated mainly from anthropogenic sources, Cu originated from both anthropogenic and natural sources, while other metals mainly originated from natural sources. The adsorption rate of trace metals in sediment samples was significantly correlated with the physico-chemical properties of the environment, whereas the uptake of trace metals by the Acropora downingi corals seemed to be dependent on their metabolic factors. Overall, the results showed that coral (Acropora downingi) reef ecosystems of the Persian Gulf are at the low to moderate risk of trace metal contamination of the bottom sediment. Overall, this study provides a 'snapshot' of the status of trace metals pollution in the coral reef ecosystems of the Persian Gulf, and also highlights the need for long-term studies in order to understand, monitor and mitigate further trace metal pollution in the region.

Following the Deepwater Horizon (DWH) spill, oil residues were found in all five Gulf states of the United States (Texas, Louisiana, Mississippi, Alabama and Florida). However, only a small amount was found in Texas, leading to speculation that it may have arrived there via ship through bilge water instead of naturally via currents. We report on a numerical modeling effort to simulate surface drifters during and after the DWH spill to demonstrate that surface water parcels – and therefore oil carried by those parcels – could reasonably have reached Texas waters at the appropriate time and location from known oiled locations without human interference. We additionally give context for the conditions in 2010 through a study of summer connectivity with the Galveston Bay coastline, which shows that in some years oil from the DWH pipe likely would not have reached Texas.

In this study, we used flow cytometry to examine how incubation in dark versus light affects the vitality and viability of UV-irradiated Tetraselmis suecica. High UV doses (300 and 400 mJ/cm²) affected the esterase activity, membrane permeability, and chlorophyll content more when the subsequent incubation took place in light. For non- or low UV dose (100 and 200 mJ/cm²)-treated cells, incubation in light resulted in cell regrowth as compared to incubation in dark. Damaged cells (enzymatically active but with permeable membranes) did not recover when incubated under light or dark conditions.Exposure to light reduces the evaluation time of any given ballast water treatment, as viable cells will be detected at an earlier stage and the vitality is more affected. When evaluating the performance of UV-based ballast water treatment systems (BWTS), these results can be useful for type approval using T. suecica as a test organism in the test regime.

We investigated the environmental partitioning and particle characteristics of macro-, meso- and microplastics and their uptake into the mussel, Mytilus edulis. Sediment samples, overlying seawater and mussels from 9 intertidal locations in the South West of England were analysed for abundance and type of microplastic. Micro- and mesoplastic-like particles were found in 88.5% of the 269 mussels sampled, ranging from 1.43 to 7.64 items per mussel. Of these plastic particles, 70.9% were identified as semi-synthetic (mainly modified-cellulose). Mussel microplastic abundance, but not polymer type, was correlated with that of their surrounding sediment, but not with sea-surface microplastic concentration or mussel size for our study sites. We found significant differences in the relative abundance of polymer types and particle sizes between seawater, sediment, and mussels, with mussels over-representing modified-cellulose fibre abundance but under-representing polyvinyl. Mussels contained significantly smaller plastic fragments than their surrounding sediment and shorter fibres than their overlying seawater.

Silver (Ag) is a non-essential metal known to bioaccumulate in aquatic organisms. We determined Ag concentrations in five false killer whales stranded in South America. Silver concentrations (in dry weight basis) range as 6.62–10.78 μg g⁻¹ in liver, 0.008–7.41 μg g⁻¹ in spleen, 0.004–5.71 μg g⁻¹ in testis, 0.757–1.69 μg g⁻¹ in kidney, 0.011–0.078 μg g⁻¹ in lung and < 0.01–0.038 μg g⁻¹ in muscle, whereas in the single samples of uterus and ovary were 0.051 and 0.023 μg g⁻¹; respectively. Overall, Ag concentration in liver and kidney exceeded the cetacean toxic thresholds, proposed as “unhealthy concentrations” and “critically dangerous” in liver and kidney. These results warrant further eco-toxicological studies, to examine biological effects of elevated silver levels for individuals and to assess the species' conservation status with respect to marine pollution.

We studied the bioaccumulation of metals and PAHs, the pathological conditions, regressive phenomena and pathogens in wild Mytilus galloprovincialis taken along the North Pier facing the former second Italian largest steelworks of Bagnoli. There was no Cd and Pb bioaccumulation with respect to the EU role 221/2002. Metal shell index decreased as follows: Pb > Ni > Zn > Cu and correlates with the pollution state. The level of BaP was up to thirtysixfold higher the EU rule 835/2011. The sum of 4 hydrocarbons, PAH4, were up to seventeen-fold the rule. PAH levels increased toward the coast. Prevalence values of tissue necrosis and inflammatory lesions were between 50 and 100%. In May animals showed lesion like granulocytomas and inflammatory capsules. Signs of atresia, necrotic oocytes and diffused cases of hermaphroditism were detected. An appropriate localization of farming to avoid contamination from sediment turbulence and risks for consumer health is needed.