In atoll lagoons of French Polynesia, growth and reproduction of pearl oysters are mainly driven by plankton concentration. However, the actual diet of black-lip pearl oysters Pinctada margaritifera in these lagoons is poorly known. To fill this gap, we used the flow through chamber method to measure clearance rates of P. margaritifera in Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia). We found: (i) that pearl oysters cleared plankton at a rate that was positively related to plankton biovolume, (ii) that nanoflagellates were the main source of carbon for the pearl oysters, and (iii) that the quantity and origin of carbon filtrated by pearl oysters was highly dependent on the concentration and composition of plankton. These results provide essential elements for the comprehension of growth and reproduction variability of pearl oysters in atoll lagoons of French Polynesia.

The microbiological pollution of coastal waters is a major problem, especially in shellfish areas. This article shows the faecal contamination in bivalves from the Ria Formosa Lagoon (south coast of Portugal) along 20years (1990–2009). The highest values of Escherichia coli in bivalves were obtained during the 90s, related with the discharge of untreated wastewaters and agricultural runoff. In the 2000s contamination levels decreased, with 83% of the population already served by new or remodelled sewage treatment plants. The highest levels were found in bivalves close to the largest city, where punctual and diffuse contamination sources still exist. Bivalves from the less impacted site showed the lowest contamination, an area with more water renewal. Seasonally, the highest levels were in autumn and winter, due to the runoff of waters from rainfall. These were opposite to those in spring and summer, when the highest temperatures and salinity showed a bactericidal effect.

Neustonic microplastic and zooplankton abundance was determined in the North Western Mediterranean Sea during a summer cruise between July 9th and August 6th 2010, with a break between July 22th and 25th due to a strong wind event. Ninety percent of the 40 stations contained microplastic particles (size 0.3–5mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116particles/m² was observed. The highest abundances (>0.36particles/m²) were observed in shelf stations. The neustonic plastic particles concentrations were 5 times higher before than after the strong wind event which increased the mixing and the vertical repartition of plastic particles in the upper layers of the water column. The values rise in the same order of magnitude than in the North Pacific Gyre. The average ratio between microplastics and mesozooplankton weights was 0.5 for the whole survey and might induce a potential confusion for zooplankton feeders.

Baseline activity concentration of ¹³⁷Cs, ²¹⁰Po and ²¹⁰Pb was determined for 25 resident and 22 migratory fish species collected in a so-called wedge bank region in the extreme south of India. A nuclear power station is now under construction at Kudankulam near the target region and the data provide background information on the radionuclide activity concentration in the region. Three-way ANOVA revealed no significant variation in the concentrations of ¹³⁷Cs, ²¹⁰Po and ²¹⁰Pb between species based on feeding habit, habitat and migratory pattern except the effect of feeding habit on ²¹⁰Po concentration (p<0.05). The annual dose due to radionuclide ingestion through the fishes was calculated based on the survey results of fish consumption rates for the local population. The dose due to ¹³⁷Cs was negligibly small while those due to ²¹⁰Po and ²¹⁰Pb varied from 1.2 to 36.9 and 0.2 to 2.9μSvyr⁻¹, respectively.

The impact of drilling mud components on the filtration activity and survival of bivalve molluscs was investigated by exposing them to suspensions of ‘standard’ barite, finely milled barite, ilmenite and bentonite in sea water. Introduction of the components stimulated filtration activity in all four bivalves. In addition, the introduction of standard barite and ilmenite both had lethal effects, with none of the bivalves surviving the full duration of the experiments. In-vivo observations of the gill surfaces provided direct evidence of physical damage caused by the administration of barite and ilmenite. A marked difference between filtration activity and survival of animals dosed with ‘standard’ barite and ‘fine’ barite suggests that the observed effects were primarily caused by physical interference with gill function. The results also suggest that the use of fine barite in offshore drilling may provide a more favourable environmental impact profile than the use of ilmenite.

Due to economic importance of Guanabara Bay, a multidisciplinary approach was adopted to investigate 88 surficial sediment samples in order to use the benthic foraminifera as indicators for the characterization of environmental variations. Grain-size analyses indicate that bottom sediments of the inner part of the bay are mainly muddy while those close to the entrance of the bay are sandy. Geochemical data show high concentration of heavy metals mainly in the northern region of the bay. Micropalaeontological analyses indicate the boundaries of the areas with the highest concentration of heavy metals. The dominant benthic foraminifera in the bay are Ammonia beccarii and Buliminella elegantissima, taxa capable of differentiating the presence of pollutants of different sources. B. elegantissima, in particular, has shown to be an indicator of anthropogenic pollution. The study highlights the worsening of environmental conditions since 2000 and those areas of the bay in need of a priority recovery.

Diatom indices are used to evaluate the ecological status of rivers but they have been rarely applied in estuaries. This study aimed to identify the diatom species indicating the main environmental gradients and pressures in a highly stratified estuary; and to evaluate the applicability of existing freshwater diatom indices. Marine influence due to salt-wedge intrusion and sea water mixing appeared as the main factor affecting diatom community. Three diatom assemblages were identified: indicators of riverine conditions (without marine influence), indicators of estuarine conditions (heterogeneous conditions with higher conductivities due to marine influence) and those specifically indicating well-established salt-wedge situations. Nowadays, the main human pressure affecting diatom community in the Ebro Estuary is the hydrological alteration resulting from flow regulation and abstraction. Several limitations were encountered in the application of diatom indices (e.g. inverse response with nutrients; ecologically important species not considered). Therefore, their use in estuaries should be done cautiously.

In this paper, we described the applications of two-photon laser confocal scanning microscopy (TPLCSM) for in situ monitoring and visualizing the localizations and movements of naphthalene, phenanthrene, and pyrene into living Aegiceras corniculata (L.) Blanco seedlings (A. corniculata). Experimental results demonstrated that all of the polycyclic aromatic hydrocarbons (PAHs) were observed entering into the root of A. corniculata and being transmitted to the stem. The transport processes and subsequent storages of the three typical PAHs into A. corniculata were similar. Further studies indicated that the transmission rates of the PAHs in A. corniculata were in the order of naphthalene>phenanthrene>pyrene. Compared with the control group, the growth of the A. corniculata was inhibited by these three specific PAHs, and the inbibitional effect of naphthalene was the most obvious (P<0.05). Furthermore, without the need for sample manipulation or modification this TPLCSM provides us a real-time tool for direct observation of organic chemicals within plants.

Within the context of risk evaluation of chemical spillages into the marine environment, this paper reports on an offshore experiment to study the behaviour of styrene spilled into sea under natural conditions and discusses theoretical approaches. Floating structures were used to enclose the spillage and the gaseous cloud formation, and dissolution processes were in situ monitored. The identification of spill risks for man and marine environment through GESAMP’s hazard profile is described for styrene: Styrene is rated as a chemical with a significant health hazard that will float but also evaporate. However, monitoring of the water column in the experiments showed that the concentration of styrene in water during the first hour represents 50% of the product spilled. For the potentially exposed public, the GESAMP hazard rating recommends the closure of beaches and evacuation. The risk assessment developed from experimental data confirms this safety advice.

The anthropogenic pressures on coastal areas represent important factors affecting local, regional, and even global patterns of distribution and abundance of benthic organisms. This report undertakes a comparative analysis of the community structure of rocky shore intertidal phytobenthos in both pristine like environments (PLE) and urbanized environments (UBE) in southern Brazil, characterizing variations on different spatial scales. Multivariate analysis of variance indicated that the PLE is characterized by a larger number of taxa and an increased occurrence of Rhodophyta species in relation to UBE. In contrast, UBE were dominated by opportunistic algae, such as Cladophora and Ulva spp. Significance tests further indicated higher species richness and Shannon–Wiener diversity on the PLE in relation to UBE. Here we provide data showing the magnitude of seaweed biodiversity loss and discuss direct and indirect consequences of unplanned urbanization on these communities.