Euplotes crassus, a single-celled eukaryote, is directly affected by environmental contaminants. Here, exponentially cultured E. crassus were exposed to cadmium, copper, lead, and zinc and then the reactive oxygen species (ROS) and total glutathione (GSH) levels were measured. Subsequently, the transcriptional modulation of glutathione peroxidase (GPx) and glutathione reductase (GR) were estimated by quantitative RT-PCR. After an 8-h exposure, significantly higher increases in the relative ROS and total GSH levels were observed in exposed group, compared to the controls. Real-time PCR data revealed that the expression levels of GPx and GR mRNA were sensitively modulated within 8h of exposure to all heavy metals. These findings suggest that these genes may be involved in cellular defense mechanisms by modulating their gene expression against heavy metal-induced oxidative stress. Thus, they may be useful as potential molecular biomarkers to assess sediment environments for contaminants.

In recent decades, the Anzali wetland has been threatened and destroyed by environmental pollution from several sources. The purpose of this study was to determine the possible relationships between mercury concentrations in Pike and their respective sediments within the assumed multiple activity center scales of Pike (100, 250 and 500m in radius). To gain a better understanding spatial distribution pattern of Hg in sediments and to pursue the main purpose of this study, kriging (geostatistic spatial interpolation method) was applied. Poor relationships were found between mercury concentrations of Pike and sediments within the assumed multiple activity center scales of Pike. The mercury sediment influence diminished with the increasing radii of assumed activity centers. The results of the present study indicate that fish and sediment mercury concentrations in western parts of the Anzali wetland were low in comparison with the concentrations reported in the literature from other regions.

Large amounts of waste water are discharged from the Jeddah Metropolitan Area into the Red Sea. Daily loads of total nitrogen (TN) and phosphorus (TP) amount to 6564kg and 2241kg, respectively, comprising 83% of dissolved inorganic nitrogen and 33% of dissolved phosphate. Steep gradients prevail nearshore, ranging from 2000μMTN and 250μMTP in the hypertrophic city lagoons to 6μMTN and 0.4μMTP in the adjacent oligotrophic water. Sewage inputs from Al Khumra, Jeddah’s main outfall, cause a widespread but moderate increase in surface nutrient concentrations due to the submerged diffuser. The nutrient pool in the oligotrophic water is dominated by dissolved organic and particulate forms, with nitrate frequently below the detection limit, indicating rapid transformation of inorganic nutrients. N:P ratios, as well as half-saturation constants for phytoplankton growth, suggest that nitrogen is the limiting factor restricting primary production in the area.

Sediment samples from 13 sampling sites in Deception Bay, Australia were analysed for the presence of heavy metals. Enrichment factors, modified contamination indices and Nemerow pollution indices were calculated for each sampling site to determine sediment quality. The results indicate significant pollution of most sites by lead (average enrichment factor (EF) of 13), but there is also enrichment of arsenic (average EF 2.3), zinc (average EF 2.7) and other heavy metals. The modified degree of contamination indices (average 1.0) suggests that there is little contamination. By contrast, the Nemerow pollution index (average 5.8) suggests that Deception Bay is heavily contaminated. Cluster analysis was undertaken to identify groups of elements. Strong correlation between some elements and two distinct clusters of sampling sites based on sediment type was evident. These results have implications for pollution in complex marine environments where there is significant influx of sand and sediment into an estuarine environment.

Review is devoted to the analysis of a radioecological situation in the North-western Black Sea and concerns the levels of contamination of the components of an ecosystem by the main artificial radioactive isotopes (90Sr, 137Cs, 239,240Pu). The long-term accumulation trends of these radionuclides were analyzed in components of the Black Sea ecosystem after the Chernobyl nuclear power plant accident. Zones that have an increased ability to accumulate these radioisotopes were revealed. The assessment of irradiation dose rates formed by 90Sr, 137Cs and 239,240Pu in Black Sea hydrobionts was obtained. The strategy for biodiversity conservation and sustainable management of natural resources should include monitoring of the radioecological state of the marine ecosystems, and the formation of a complex of biogeochemical criteria for assessment of an ecological situation in the sea. This approach is important for marine protected areas, since it allows the formation of a basis for scientific and practical function.

We examined the bacterial accumulation and digestion in the alien polychaete Branchiomma bairdi. Microbiological analyses were performed on worm homogenates from “unstarved” and “starved” individuals and on seawater from the same sampling site (Ionian Sea, Italy). Densities of culturable heterotrophic bacteria (22°C), total culturable bacteria (37°C) and vibrios were measured on Marine Agar 2216, Plate Count Agar and TCBS Agar, respectively. Microbial pollution indicators were determined by the most probable number method. B. bairdi was able to accumulate all the six considered microbiological groups which, however, differ in their resistance to digestion. B. bairdi results more efficient than the other two co-occurring sabellids in removing bacteria suggesting that it may counteract the effects of microbial pollution playing a potential role for in situ bioremediation. Thus a potential risk, such as the invasion of an alien species, could be transformed into a benefit with high potential commercial gain and economic feasibility.

Recently compiled databases facilitated estimation of basin-wide benthic organic biomass and turnover in the Strait of Georgia, an inland sea off western Canada. Basin-wide organic biomass was estimated at 43.1×106kgC and production was 54.6×106kgCyr−1, resulting in organic biomass turnover (P/B) of 1.27×yr−1. Organic biomass and production for sub-regions were predictable from modified organic flux (r2>0.9). P/B declined significantly with increasing modified organic flux, suggesting greater biomass storage in high flux sediments. Biomass and production were highest, and P/B lowest near the Fraser River. Annual basin-wide benthic production was 60% of previously estimated oxidized organic flux to substrates, which agrees with proportional measurements from a recent, localized study.Deviations from expected patterns related to organic enrichment and other stressors are discussed, as are potential impacts to benthic biomass and production, of declining bottom oxygen, increasing bottom temperature and potential changes in riverine input.

224Ra and 223Ra are adopted as tracers to qualify submarine groundwater discharge (SGD) in Tolo Harbor, a highly urbanized embayment in Hong Kong. Based on the sampling data, a two-layered radium mass balance model is used to estimate lateral SGD and bottom SGD. Total SGD is estimated to be 1.2–3.0cmd−1, including lateral SGD of 5.7–7.9cmd−1 and bottom SGD of 0.3–2.0cmd−1. Fresh SGD is estimated to be (2.1–5.5)×105m3d−1. Nutrient fluxes (mold−1) from SGD are estimated to be (3–7.4)×104 (dissolved inorganic nitrogen), (2.4–6.2)×102 (dissolved inorganic phosphate) and (6.5–16)×104 (dissolved silicate). Primary productivity is estimated to be (1.5–15)×106gCd−1, 2–53% of which is supported by SGD-induced phosphate fluxes. The study indicates that SGD is a significant source of nutrients to coastal waters and may cause an obvious increase of primary production. These findings must be considered in future coastal ecological management.

The distributions of dissolved methane in the central Bohai Sea were investigated in November 2011, May 2012, July 2012, and August 2012. Methane concentration in surface seawater, determined using an underway measurement system combined with wavelength-scanned cavity ring-down spectroscopy, showed marked spatiotemporal variations with saturation ratio from 107% to 1193%. The central Bohai Sea was thus a source of atmospheric methane during the survey periods. Several episodic oil and gas spill events increased surface methane concentration by up to 4.7 times and raised the local methane outgassing rate by up to 14.6 times. This study demonstrated a method to detect seafloor CH4 leakages at the sea surface, which may have applicability in many shallow sea areas with oil and gas exploration activities around the world.

This paper reports the results of an analysis of oil spill cost data assembled from a worldwide pollution database that mainly includes data from the International Oil Pollution Compensation Fund. The purpose of the study is to analyze the conditions of marine pollution accidents and the factors that impact the costs of oil spills worldwide. The accidents are classified into categories based on their characteristics, and the cases are compared using charts to show how the costs are affected under all conditions. This study can be used as a helpful reference for developing a detailed statistical model that is capable of reliably and realistically estimating the total costs of oil spills. To illustrate the differences identified by this statistical analysis, the results are compared with the results of previous studies, and the findings are discussed.