In-situ burning during the Deepwater Horizon oil spill generated tens of thousands of barrels of in-situ burn (ISB) residues in the northern Gulf of Mexico (GoM), most or all of which eventually sank to the seafloor. Chemical analyses showed that floating and sunken (~1400m deep) ISB residues (1) exhibited distinct n-alkanes and UCM profiles inconsistent with vapor-pressure driven evaporation, (2) were relatively enriched in pyrogenic PAHs, particularly less stable (mostly) linear PAH isomers formed during burning, and (3) had lost petroleum biomarkers, relative to their volatility. PAH concentrations in ISB residues indicate that between 26,800 and 37,800kg of total PAHs (TPAH51) and 2880 and 4060kg of 16 Priority Pollutant PAHs were potentially deposited on the seafloor in discrete ISB residue particles. Despite this additional benthic impact, ISB reduced the total mass loadings of PAH from the burned oil to the GoM by 89% (ignoring any re-deposition from atmospheric emissions).

Methodologies developed by European Member States to assess the environmental quality of their coastal waters under the EU Water Framework Directive (WFD, 2000/60/EC) may have an associated source of uncertainty. Here we identify and quantify the level of uncertainty in the CARLIT (Cartography of littoral and upper-sublittoral communities) methodology to test its effectiveness and reliability. The outcomes show that the effect of temporal variability (among years) within each water body is low when CARLIT is performed every year along the entire rocky coast. The spatial variability within a water body is also low. According to these results, CARLIT could be performed every 3years across all the water body or, alternatively, every year considering at least 60% of each water body, without a significant reduction of the confidence in the classification of the Ecological Quality Status (EQS).

Oman contains diverse and abundant reef coral communities that extend along a coast that borders three environmentally distinct water bodies, with corals existing under unique and often stressful environmental conditions. In recent years Oman's reefs have undergone considerable change due to recurrent predatory starfish outbreaks, cyclone damage, harmful algal blooms, and other stressors. In this review we summarize current knowledge of the biology and status of corals in Oman, particularly in light of recent stressors and projected future threats, and examine current reef management practices. Oman's coral communities occur in marginal environmental conditions for reefs, and hence are quite vulnerable to anthropogenic effects. We recommend a focus on developing conservation-oriented coral research to guide proactive management and expansion of the number and size of designated protected areas in Oman, particularly those associated with critical coral habitat.

General abundance and species composition of a dinoflagellate community in Yemeni coastal waters of Al Salif (southern Red Sea) were studied with a view to understand the annual variations in particular the toxic species. Dinoflagellates were more abundant among phytoplankton. Thirty five dinoflagellate taxa were identified, among which 12 were reported as potentially toxic species. A significant change in seasonal abundance was recorded with the maximum (2.27∗106cellsl−1) in May, and the minimum (2.50∗102cellsl−1) recorded in January. Kryptoperidinium foliaceum, which was reported for the first time from the Red Sea, was the most abundant species with a maximum in May 2013 (2.26∗106cellsl−1). Spearman's rank correlation analysis indicates that, total harmful dinoflagellate cells, K. foliaceum, Prorocentrum gracile and Prorocentrum micans were significantly correlated with temperature. This study suggests that Yemeni waters should be monitored to investigate harmful species and to identify areas and seasons at higher risk.

The effect of ozonation on treatment of diesel-contaminated water was investigated on a laboratory scale. Factorial design and response surface methodology (RSM) were used to evaluate and optimize the effects of pH, ozone flow rate, and contact time on the treatment process. A Box–Behnken design was successfully applied for modeling and optimizing the removal of total petroleum hydrocarbons (TPHs). The results showed that ozonation is an efficient technique for removing diesel from aqueous solution. The determination coefficient (R2) was found to be 0.9437, indicating that the proposed model was capable of predicting the removal of TPHs by ozonation. The optimum values of experimental initial pH, degree of O3, and reaction time were 7.0, 1.5, and 35min, respectively, which could contribute to approximately 60% of TPH removal. This result is in good agreement with the predicted value of 57.28%.

Concern over the loss of mangrove ecosystems often focuses on their role in protecting coastal communities from storms that damage property and cause deaths and injury. With climate change, mangrove loss may also result in less protection against coastal storms as well as sea-level rise, saline intrusion and erosion. Past valuations of the storm protection benefit of mangroves have relied on the second-best replacement cost method, such as estimating this protective value with the cost of building human-made storm barriers. More reliable methods instead model the production of the protection service of mangroves and estimate its value in terms of reducing the expected damages or deaths avoided by coastal communities. This paper reviews recent methods of valuing the storm protection service of mangroves and their role in protecting coastal areas and communities of tropical developing countries.

Mercury (Hg) contamination is an issue of a growing environmental and public health concern. Atmospheric chemistry transport models for Hg are a critical tool for understanding the sources, processes, and fate of Hg. Uncertainties in multiple aspects of atmospheric Hg models, however, limit their application for policy evaluation and for monitoring global trends in atmospheric Hg concentrations. This review aims to identify uncertainties in atmospheric Hg modeling that are relevant in the context of policy and for informing decision-making. We focus on specific requirements of the Minamata Convention on Mercury, a global treaty signed in 2013 to protect human health and the environment from Hg, to demonstrate how existing uncertainties in atmospheric Hg modeling can influence our ability to evaluate source-receptor relationships. Modeling studies of source attribution suggest that major uncertainties in atmospheric Hg modeling arise from anthropogenic emissions, biogeochemical cycling, and atmospheric chemistry. Uncertainties in these aspects of modeling are expected to increase under the Convention, with regulation of anthropogenic emissions, changes in atmospheric conditions, and legacy and natural Hg source contribution to the global biogeochemical cycle. These uncertainties can interact with one another and with the current Hg species measurement capability and pose challenges to effectively monitoring trends in atmospheric Hg. Developing additional means to attribute simulated atmospheric Hg trends and improve source-receptor relationships in atmospheric Hg models would improve our ability to evaluate the Convention’s effectiveness.

Understanding the patterns of genetic diversity of fish species is essential for marine conservation and management. This is particularly important in the Arabian Gulf where marine life is subject to extreme environmental conditions that could impact genetic diversity. Here we assess genetic diversity of the most commercially important fish in the United Arab Emirates; groupers (Epinephelus spp.). Sequencing of 973bp mitochondrial DNA from 140 tissue samples collected in four main fish markets revealed 58 haplotypes clustered within three groups. Data analysis revealed the presence of three distinct Epinephelus species being marketed as one species (hammour): Epinephelus coioides, Epinephelus areolatus and Epinephelus bleekeri. We report species-specific genetic markers and demonstrate that all three species exhibit relatively low levels of genetic variation, reflecting the effect of overfishing and environmental pressures. In light of the genetic evidence presented here, conservation and management of groupers in the UAE warrant the implementation of species-specific measures.

Bioaugmentation, Biostimulation and Horizontal gene transfer (HGT) of catabolic genes have been proven for their role in bioremediation of hydrocarbons. It also has been proved that selection of either biostimulation or bioremediation varies for every contaminated site. The reliability of HGT compared to biostimulation and bioremediation was not tested. The present study focuses on reliability of biostimulatiion, bioaugmentation and HGT during biodegradation of Diesel oil and Non aqueous phase liquids (NAPL). Pseudomonas aeruginosa (AEBBITS1) having alkB and NDO genes was used for bioaugmentation and the experiment was conducted using seawater as medium. Based on Gas chromatography results diesel was found to be degraded to 100% in both presence and absence of AEBBITS1. Denturing gradient gel electrophoresis result showed same pattern in presence and absence of AEBBITS1 indicating no HGT. NAPL degradation was found to be more by Biostimulated Bioaugmentation compared to biostimulation and bioaugmentation alone. This proves that biostimulated bioaugmentation is better strategy for oil contamination (tarabll) in Velsao beach, Goa.

In this study, we analyzed the relationship between concentration of metals in the host-parasite system (cod - acanthocephalan Echinorhynchus gadi) and Fulton's condition factor (FCF) of the host. The relationship between metal (Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Pb, Sr, Zn) concentrations in E. gadi and cod tissues was expressed as a bioconcentration factor (BCF), the ratio of the concentration in the parasite tissue to that in host tissues. Acanthocephalans accumulated mainly toxic metals (Cd, Pb), as well as Sr, Ca, Na. Cadmium showed the highest bioconcentration in parasites (BCF >200) compared to fish muscle. Significant negative correlation was detected between FCF and the concentration of Cd and Hg in cod liver. In contrast, FCF was positively correlated with the concentration of Hg in acanthocephalan tissues.