Trajectory estimation of an oil spill in ice-covered waters is essential for response planning and risk assessment. This paper presents the preliminary development of a new computational model for the estimation of spreading and surface transport of oil in the presence of ice. A new approach for the estimation of spreading in 0.8–0.95 ice concentration range is proposed. Additionally, for the first time the pumping of floating in‑leads oil onto or under ice floes with closing leads is modelled. The model is able to estimate the mobilization of under-ice oil and its potential subsequent surfacing and works as a stand-alone model with any rectangular-grid ice-ocean model. The model was used to simulate trajectories of two real-life spill events, a field experiment in the Barents Sea where oil and ice were observed to move together and an accidental spill in the Gulf of Finland. Model results were generally consistent with observations.

Coastal eutrophication and consequent oxygen depletion (hypoxia) occurs worldwide due to increased human activity. The paucity of genomic information of microbes in hypoxia prone coastal waters have hindered our understanding of microorganism related causation and adaption to the environment. Here, using metagenomic approach, we investigated microbial metabolic capability in heavily polluted Pearl River estuary. Our results highlighted the possible roles of microbial metabolic activity in the formation of bottom water hypoxia by revealing enriched organic degradation related microbial genes in the bottom layer beneath surface phytoplankton bloom. Microbial nitrate reduction in hypoxia layer was low, possibly due to the low pH and fluctuating oxygen level. On contrary, high abundance of sulfate-reducing, and antibiotic and metal resistance related genes were detected in bottom and surface layers, respectively, indicating microbial adaptation to oxygen depletion and pollution. Our study provides gene level information on the interactive relations between microbial functions and environmental stress.

New Zealand has a complex coastal environment spanning a large latitudinal gradient and three water masses. Here we assess whether multivariate analyses of benthic macrofaunal community composition can be a sensitive approach to assessing relative estuarine health across the country, negating the need for regional indices and reducing reliance on reference sites. Community data were used in separate canonical analyses of principal coordinates to create multivariate models of community responses to gradients in mud content and heavy metal contamination. Both models performed well (R² = 0.81, 0.71), and were unaffected by regional and estuarine typology differences. The models demonstrate a sensitive and standardized approach to assessing estuarine health that allowed separation of the two stressors. This approach could be applied to other stressors, countries or regions.

The levels of some persistent organic pollutants (POPs) along the Lebanese coastal zone (LCZ) were assessed by collecting15 surface sediments from five hotspot stations. Such stations were influenced by various industrial units, riverine input, and touristic activities. The levels of polycyclic aromatic hydrocarbons (∑16PAHs), their methylated derivatives (∑18Me-PAHs), and polychlorinated biphenyls (∑28PCBs) were in the range of 537–3773 μg∙kg⁻¹ dw, 187–1541 μg∙kg⁻¹ dw, and 143–303 μg∙kg⁻¹ dw respectively. Significant contamination was found at Beirut Port that is surrounded by a densely populated area and is subjected to multidisciplinary activities. Source identification of PAHs was confirmed by using the diagnostic ratio of PAHs with low molecular weight and high molecular weight (LMW/HMW). For PCBs, LCZ is polluted by higher chlorinated congeners with 4 to 9 chlorinated atoms generated from volatilization and combustion processes. Toxicity and biological risks were assessed using toxic equivalent quantity (TEQcarc) and sediment quality guideline quotient (SQGq).

Due to rapid urbanization and industrialization, heavy metal (HM) pollution in coastal areas of the East China Sea (ECS) has attracted extensive attention. This article attempts to review recent studies on the temporal and spatial distributions, ecological risks, and possible sources of HMs in typical bays and estuaries of ECS. The levels of HMs are closely related to local economic development and local characteristics. The anthropogenic activities and the particle size of sediments are important factors affecting the distribution of HMs. During the late 1970s to the 1990s, HMs levels in the Yangtze Estuary (YRE) sediments showed an upward tendency due to the increased emissions. However, HMs levels in the early 2000s were lower than that in the late 1970s to the mid-1990s. Cd caused serious pollution and brought potential ecological risks in the Yangtze Estuary, Hangzhou Bay (HZB), Sanmen Bay (SMB), and Quanzhou Bay (QZB). In Fujian province of China, the Quanzhou Bay was heavily polluted by HMs and high contents of HMs were found in biota. Among different species, molluscs in the coastal areas of ECS have the highest levels of HMs exceeding safety limits.

A dinoflagellate under the ambit of Harmful Algal Blooms (HAB), the bioluminescent Noctiluca scintillans (NS), has been infesting the northern Arabian Sea increasingly over the last few decades during late winter. Their occurrence is found to be due to seasonal oscillations in the coastal currents. The physical and biogeochemical parameters associated with the seasonal blooms are reasonably well known. But accurate quantitative estimation capability using remote sensing sensors over the extensive oceanic regime is still lacking. This is especially due to a lack of information on bio-optical properties associated with cell density measurements. We attempted to show that remote sensing reflectance and chl-a show significant relationship e.g., Rᵣₛ(531)/Rᵣₛ(510) = 0.8261 + 6.06 × 10⁻⁶NS + 0.02323chl-a (N = 19, R²ₐdⱼ = 0.99, p = 2.5 × 10⁻¹⁷, RMSE = 0.1083) which is applicable over diverse areas of the northeastern Arabian Sea e.g., coastal, shelf and offshore regions. The model is supported by a second dataset with an RMSE of 0.022893 (N = 8) for the Rᵣₛ(531)/Rᵣₛ(510) ratio. The NS cell densities were derived from the Rrs(510)/Rrs(531) band ratio within reasonable error and accuracy limits. Including sensor capability at 510 nm is suggested in future satellite launches.

The water filtering capacity, and the potential to accumulate contaminants such as heavy metals, make marine sponges suitable candidates for biomonitoring of marine ecosystems. Sponges also harbor a variety of endosymbionts, including fungi, which could be affected by the accumulation of contaminants. This work examined the bioaccumulation factors of heavy metals by sponges from coastal waters from Puerto Rico. Fungal communities associated with marine sponges were assessed to determine if their composition co-varied with heavy metals in sponge tissue. All sponges in our study where found to bioaccumulate arsenic, cadmium and copper. Fungi associated with the sponges showed variations in community composition among localities and sponge species. Our results suggest that sponges, specially Tedania ignis, could be used as a complementary component for biomonitoring of arsenic, cadmium and copper; and that members of the harbored fungal communities could be negatively affected by the accumulation of heavy metals in the sponges.

Microplastic particles (<5 mm) constitute a growing pollution problem within coastal environments. This study investigated the microplastic presence of estuarine and barrier island beaches in the states of Virginia and North Carolina, USA. Seventeen sediment cores were collected at four study sites and initially tested for microplastic presence by pyrolysis-gas chromatography–mass spectrometry. For the extraction, microplastic particles were first separated from the sediment using a high-density cesium chloride solution (1.88 g/mL). In a second step, an oil extraction collected the remaining microplastic particles of higher densities. Under the light microscope, the extracted microplastic particles were classified based on their morphologies into fragments and fibers. Raman microspectroscopy chemically identified a subset of microplastic particles as polypropylene, polyethylene terephthalate, poly(4-vinylbiphenyl), polystyrene, polyethylene, and nylon. The results show a concentration of microplastic particles (1410 ± 810 per kg of dry sediment) even in protected and ostensibly unpolluted estuarine and beach sediments of Virginia and North Carolina.

The distribution and bioconcentration of polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate material (SPM), algae, and zooplankton samples from the Pearl River Delta (PRD), South China, were investigated. The PAHs in the water and SPM samples is significantly associated with chlorophyll a (Chl a), implying the important role of the aquatic productivity on PAH distribution. PAHs in the water or SPM samples were strongly correlated to dissolved organic carbon (DOC) or algal particulate organic carbon (A-POC). Moreover, the log bioconcentration factor (BCF) values (mL g⁻¹) of PAHs in both the algae and zooplankton samples were linearly related to their log octanol-water coefficient (Kow) values. However, the slopes of these relationships were negatively correlated with Chl a, attributing to the difference in the dominant plankton species or the non-equilibrium exchange between air-water-biota. The above results indicate the important role of trophic levels on the distribution and bioaccumulation of PAHs.

Global increase in the use of pharmaceutically-active compounds (PhACs), and their insufficient removal in wastewater treatment plants, have resulted in their continuous release into the marine environment. We investigated the use of the solitary ascidians Herdmania momus, Microcosmus exasperatus, and Styela plicata as bioindicators of three common PhACs in the Israeli coastal waters: Bezafibrate, carbamazepine and diclofenac. Both the Mediterranean and the Red-Sea coasts were found contaminated with PhACs, detected at all 11 sampling sites, with four sites contaminated with all three studied PhACs. Diclofenac was most frequent, present in nine of the 11 sites with concentrations reaching 51.9 ng/g of dry weight sample (dw). Bezafibrate and carbamazepine reached concentrations of 47.8 ng/g dw and 14.3 ng/g dw, respectively. The alarming detection of such high concentrations of PhACs in ascidians along Israel's coasts demonstrates both the extent of PhACs contamination in the region, and the potential of ascidians as bioindicators, and emphasizes the urgent need for additional research into PhAC contamination sources and effects.