We compare the chromatographic signatures of petroleum biomarkers in Deepwater Horizon (DH) source oil, three other reference crude oils, DH emulsified mousse that arrived on Alabama’s shoreline in June 2010, and seven tar balls collected from Alabama beaches from 2011 to 2012. Characteristic hopane and sterane fingerprints show that all the tar ball samples originated from DH oil. In addition, the diagnostic ratios of various hopanes indicate an excellent match. Quantitation data for C30αβ-hopane concentration levels show that most of the weathering observed in DH-related tar balls found on Alabama’s beaches is likely the result of natural evaporation and dissolution that occurred during transport across the Gulf of Mexico prior to beach deposition. Based on the physical and biomarker characterization data presented in this study we conclude that virtually all fragile, sticky, brownish tar balls currently found on Alabama shoreline originated from the DH oil spill.

The first phase of the Taparura Project aimed at restoring the north coast of Sfax (Tunisia), highly polluted by phosphate industry and uncontrolled phosphogypsum dumping. Before restoration of the north coast of Sfax, we investigated the state of the ecosystem in related coastal waters. To establish the impact of the Taparura Project, we conducted a similar study both after restoration. To discriminate natural changes over time, we extended the study to the south coast of Sfax, submitted to the same industrial pressure but not yet restored. The present study, conducted in May 2010 at 36 stations (18 on each coast, north and south), covered the spatial distribution of the microbial assemblage, nutrients, and abiotic parameters by collecting seawater samples at the surface and the water–sediment interface. Results revealed a striking difference between the two coasts regarding pH, with strong acidification of seawater in the south, likely generated by industrial activity. Suspended matter was higher in the north than in the south. Flow cytometry analysis of ultraphytoplankton (<10μm) resolved six groups (Prochlorococcus, Synechococcus, nanoeukaryotes and three distinct subgroups within picoeukaryotes). In addition to these autotrophic groups, two unknown groups were characterised on the south coast. Heterotrophic prokaryotes were resolved into three groups, labelled LNA (low nucleic acid content), HNA1 and HNA2 (high nucleic acid content). Prochloroccocus, pico-nano-microphytoplankton, heterotrophic prokaryotes and ciliates were more abundant in the north, whereas Synechococcus and unknown species were more abundant in the south where chl a concentration was also higher. The results show that restoration had positive effects on the microbial assemblage of the north coast; they also highlight the strong acidification still prevalent in the south that may be responsible for the lower development of most phytoplankton groups and the occurrence of unknown species. The case for restoration of the city’s south coast is also reinforced.

Two estuary and two coastal lagoon stations along Chennai, Southeast coast of India were monitored for 1year to study both physicochemical and microbiological properties of the water. Influence of the marine environment over the systems was evident by elevated salinity levels. Considerable concentrations of total heterotrophic bacterial count and fecal bacteria such as total coliforms, fecal coliforms and fecal streptococci were observed throughout the study period which evinced a pattern of anthropogenic activities. Principle component analysis was employed for assessing the overall pattern of variation within the data sets. Climatic variation was highly correlated with changes in water quality, i.e. the Northeast monsoon and Summer had influenced considerably the microbial occurrence as well as the physicochemical parameters such as total suspended solids, chloride, sulphate and salinity. However, the effect of the Southwest monsoon was less prominent than the Northeast monsoon with its heavy rains. As both estuaries revealed elevated concentrations of polluted water, these stations can be used as indicators or alerts for the water quality along the coastal zone of Chennai.

The worlds’ oceans contain a large but unknown amount of plastic debris. We made daily collections of marine debris stranded at two sub-Antarctic islands to establish (a) physical causes of strandings, and (b) a sampling protocol to better estimate the oceans’ plastic loading. Accumulation rates at some beaches were dependent on tide and onshore winds. Most of the 6389 items collected were plastic (Macquarie 95%, Heard 94%) and discarded or lost fishing gear comprised 22% of those plastic items. Stalked barnacles (Lepas spp.) were a regular attachment on Macquarie debris but not at Heard Island. The daily accumulation rate of plastic debris on Macquarie Island was an order of magnitude higher than that estimated from monthly surveys during the same 4months in the previous 5years. This finding suggests that estimates of the oceans’ plastic loading are an order of magnitude too low.

We examine macrofaunal and physico-chemical responses to organic enrichment beneath salmon farms in contrasting flow environments, and reveal pronounced flow-related differences in the magnitude and spatial extent of effects. Total macrofaunal abundances at high flow sites were nearly an order of magnitude greater than at comparable low flow sites, representing a significant benthic biomass. These very high abundances occurred in conjunction with moderate-to-high species richness, and were evident in the absence of appreciable organic matter accumulation. Biological responses to increasing sulfide were variable; however a significant biological threshold was evident at 1500μM. Macrofaunal responses at high flow sites differed substantially from the Pearson–Rosenberg model. The atypical ecological conditions were attributed to (i) limited accumulation of fine sediments, (ii) maintenance of aerobic conditions in near-surface sediments, and (iii) an abundant food supply. Thus, enhanced resilience to organic waste at well-flushed sites appears related to both biological and physical processes.

Surface sediments samples were collected from 9 stations of the Cochin estuary during the monsoon, post-monsoon and pre-monsoon seasons and were analyzed for grain size, total organic carbon (OC), total nitrogen (TN) and stable isotopic ratios of carbon (δ13C) and nitrogen (δ15N) to identify major sources of organic matter in surface sediments. Sediment grain size is found to be the key factor influencing the organic matter accumulation in surface sediments. The δ13C values ranges from −27.5‰ to −21.7‰ in surface sediments with a gradual increase from inner part of the estuary to the seaward side that suggest an increasing contribution of marine autogenous organic matter towards the seaward side. The δ15N value varies between 3.1‰ and 6.7‰ and it exhibits complex spatial and seasonal distributions in the study area. It is found that the dynamic cycling of nitrogen through various biogeochemical and organic matter degradation processes modifies the OC/TN ratios and δ15N to a considerable degree. The fraction of terrestrial organic matter in the total organic matter pool ranges from 13% to 74% in the surface sediments as estimated by δ13C based two end member mixing model.

We examined the geographic extent of petroleum hydrocarbon contamination in sediment, seawater, biota, and seafood during/after the BP/Deepwater Horizon Oil Spill (April 20–July 15, 2010; 28.736667°N, −88.386944°W). TPH, PAHs, and 12 compound classes were examined, particularly C1-benzo(a)anthracenes/chrysenes, C-2-/C-4-phenanthrenes/anthracenes, and C3-naphthalenes. Sediment TPH, PAHs, and all classes peaked near Pensacola, Florida, and Galveston, Texas. Seawater TPH peaked off Pensacola; all of the above classes peaked off the Mississippi River, Louisiana and Galveston. Biota TPH and PAHs peaked near the Mississippi River; C-3 napthalenes peaked near the spill site. Seafood TPH peaked near the spill site, with PAHs and all classes peaking near Pensacola. We recommend that oil concentrations continued to be monitored in these media well after the spill has ceased to assist in defining re-opening dates for fisheries; closures should be maintained until hydrocarbon levels are deemed within appropriate limits.

The biogeochemistry of trace metals in nearshore sediments and mussel was studied at 15 stations along a 1000km long transect paralleling the west coast of the Gulf of California (GOC). Total trace metal (Me) and enrichment factor (EFMe) values in sediments were low due to negligible anthropogenic influence in the region. Past copper mining, however, near Santa Rosalia caused concentrations of Pb, Mn, Co, Zn and Cu which were 10–3.3×103 times greater than the average for the rest of the transect. Mussels also showed relatively high trace metal concentrations at the Santa Rosalia stations, but the variability in the spatial distribution was low and had undefined trends. Our results show that, with the exception of Co and Cu, the contamination caused by the copper mine affected sediments to a greater extent than mussels.

The Hg concentration in seawater and copepod samples collected from the area around hydrothermal vents at Kueishan Island and the adjacent marine environment in northeastern Taiwan were analyzed to study Hg bioaccumulation in copepods living in polluted and clean marine environments. The seawater collected from the hydrothermal vent area had an extremely high concentration of dissolved Hg, 50.6–256ngl−1. There was slightly higher Hg content in the copepods, 0.08–0.88μgg−1. The dissolved Hg concentration in the hydrothermal vent seawater was two to three orders of magnitude higher than that in the adjacent environment. The bioconcentration factor of the studied copepods ranged within 103–106, and showed higher dissolved concentration as the bioconcentration factor was lower. A substantial abundance, but with less copepod diversity was recorded in the seawater around the hydrothermal vent area. Temora turbinata was the species of opportunity under the hydrothermal vent influence.