peer reviewed | 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 0.3-5 mm) of various compositions: e.g., filaments, polystyrene, thin plastic films. An average concentration of 0.116 particles/m² was observed. The highest abundances (> 0.36 particles/m²) were observed in the 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.

In France, the number of PDA quickly increases in order to better protect receiving surface water bodies. Setting up design rules and maintenance guidelines is now urgent. | En France, l'installation de ZRV en vue de protéger davantage le milieu récepteur de surface est désormais fréquente. L'élaboration de règles de dimensionnement et de maintenance est désormais urgente.

International audience | Despite restrictions in emissions, heavy metals may remain a major environmental issue due to their numerous sources and their persistence. Here, we assessed current levels of 4 metals (Copper, Cadmium, Lead, Zinc) in the feathers of 91 feral pigeons (Columba livia) from 7 sites in the urbanized region of Paris. Elements were detected in all pigeons, indicating that metals persist in urbanized areas. The ratio between metal concentrations in the feathers vs. in the environment calculated using data from other studies was 2-90 times higher for cadmium than for other metals, underlying its ecological importance. Concentrations in the feathers depended on locality, suggesting that pigeons remain in local habitats at this restricted scale, as expected from previous observations. Overall, our study suggests that urban feral pigeons may represent a good model system for metal biomonitoring. (c) 2012 Elsevier Ltd. All rights reserved.

International audience

Field measurements and open-top chamber experiments using nine current European winter wheat cultivars provided a data set that was used to revise and improve the parameterisation of a stomatal conductance model for wheat, including a revised value for maximum stomatal conductance and new functions for phenology and soil moisture. For the calculation of stomatal conductance for ozone a diffusivity ratio between O(3) and H(2)O in air of 0.663 was applied, based on a critical review of the literature. By applying the improved parameterisation for stomatal conductance, new flux-effect relationships for grain yield, grain mass and protein yield were developed for use in ozone risk assessments including effects on food security. An example of application of the flux model at the local scale in Germany shows that negative effects of ozone on wheat grain yield were likely each year and on protein yield in most years since the mid 1980s.

International audience | Chronic exposure to persistent organic pollutants (POPs) in wildlife might alter the response to environmental changes through interference with the regulation of stress hormones. Here, we examined the relationship between blood concentrations of several POPs and baseline plasma corticosterone levels in the black-legged kittiwake (Rissa tridactyla) during three distinct periods in the breeding season. The concentrations of POPs and corticosterone increased, whereas body mass decreased progressively from the pre-laying period to the incubation and the chick rearing period. ∑PCB (polychlorinated biphenyls) correlated positively with the baseline corticosterone levels during the pre-laying period, which might suggest that PCBs affect the regulation of corticosterone. However, this relationship was not found during the incubation or the chick rearing period. Possible explanations are discussed with emphasis on how total stress/allostatic load is handled during different periods and conditions.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCA | International audience | The separate and combined in vitro toxic effects of antibiotics (ciprofloxacin, erythromycin, novobiocin, oxytetracycline, sulfamethazole and trimethoprim) commonly found in urban wastewater effluents were assessed on the immune parameters of Elliptio complanata at environmentally relevant concentrations. The observed responses were then compared to those produced by the physicochemical-treated wastewater effluent of a major city before and after the removal of microorganisms. Most of the selected antibiotics, separately and as mixture, induced changes in immune responses. The removal of microorganisms and fine particles from the effluent increased or decreased the resulting immunotoxic effects, depending of the observed parameter. The immunotoxic effects of erythromycin, sulfamethoxazole and trimethoprim were closely associated to the antibiotic mixture and the filtered effluent. In conclusion, the data revealed that the removal of fine particles and microorganisms from municipal effluents can alter the toxic nature of the effluent that is closely associated with the cumulative effects of antibiotics.