Environmental behaviour of inorganic pollutants present in raw and desalinated French marine sediments

International audienceIn the frame of long-term management of contaminated dredged sediments, this paper is centered on determinating the mobility of inorganic contaminants. A methodology derived from waste characterization has been developed and applied to marine sediments from Lazaret bay (Toulon, southern France) to determine the potential mobilization of inorganic pollutants in specific conditions. It consists of mineral and textural analysis combined with leaching tests. This methodology was applied to untreated, 5.8 % organic matter, light sandy silt harbor sediment and to the same sediment after a desalinization treatment. In both untreated and desalinated sediments, the contaminant content was around 26.1, 0.18, 42.5, 34, 31, 35 and 99 mg kg-1 for As, Cd, Cr, Cu, Ni, Pb and Zn, respectively. After 24 hours of time contact between deionized water and sediments, contaminant release of metals was very low (ca. <0.7 total mass %, for all studied elements) due to low solubility of the bearing solid phases (organic matter, carbonates and sulfides), while Mo and B were widely released. After 48 hours, Cd, As, Mo and B release was higher while more significant but no clear differences for other metal appeared

Planification côtière en Afrique de l'Ouest : retour d'expérience en Guinée-Bissau.

National audienceThis contribution reports the context of implementation of a GIS which is intented for coastal planning in Guinea Bissau in the context of the creation of a biosphere reserve. It takes stock of the productions of 10 years of collaboration between research and management of the north and the south. This experiment has become a model in the coastal countries of West Africa.Cet article relate le contexte de la mise en oeuvre d'un SIG à vocation de planification côtière en Guinée-Bissau dans le contexte de création d'une réserve de biosphère. Il fait le bilan des productions et des acquis de 10 ans de collaboration entre des organismes de recherche et de gestion territoriale du nord et du sud. Une expérience qui fait école au sein des pays côtiers d'Afrique de l'Ouest

Sexe et âge ratios chez le canard siffleur Anas penelope L. en période hivernale en Europe de l'Ouest

Data on the sex- and age-ratios of Wigeon were collected over five years. In the Camargue, data from three winters show that adult males arrived earlier than other birds ; that immature males passed through the delta in autumn and spring ; and that the sex-ratio remained remarkably stable (1.5 males per female). Short term observations over two winters covering western Europe (Spain-Holland, and Morocco-Holland) provided evidence for spatial segregation of the main sex- and age-classes. Adult males tended to remain further north in the wintering area, with immature males and the females further south. This difference in distribution was more pronounced between age-classes than between the sexes. It is suggested that aggression, through social hierarchies, may be one factor which causes these differences in distribution. Males dominate the Wigean population numerically even in the south of the wintering area. It is suggested that this unequal distribution of the ages and sexes, whatever its cause, may have important consequences for the species'demography2014-12-19T14:26:53

Plant dispersal by teal (Anas crecca) in the Camargue: duck guts are more important than their feet

12 páginas, 3 figuras, 4 tablas.1. Migratory waterbirds are major vectors for the dispersal of aquatic plants. However, quantitative field studies of the frequency of transport are scarce, and the relative importance of internal and external transport remains unclear. 2. We quantified and compared the rates of internal and external transport of aquatic plant propagules by teal (Anas crecca) in the Camargue (southern France), inspecting the lower gut contents of birds that had been shot (n = 366) and washing birds that had been live-trapped (n = 68) during the winters of 2006–2007 and 2007–2008. 3. Intact propagules (n = 902) of 21 plant taxa were recorded in the rectum of teal, of which 16 germinated or were shown to be viable. Intact propagules were recorded in the rectum of 20% of teal, with up to 171 propagules per individual bird. Chara oogonia were most abundant (60% of intact propagules), suggesting that small size favours internal transport. Eleocharis palustris, Juncus spp. and Potamogeton pusillus (17, 7 and 6% of intact propagules, respectively) were also very abundant. 4. Intact propagules (n = 12) of 10 plant taxa were found on the outside of live teal, and four of these taxa later germinated. Intact propagules were found on 18% of teal. No teal was found to carry more than one propagule externally. There was no difference in size between propagules transported internally and externally. 5. Teal are major dispersers of plants within the Camargue, despite being highly granivorous. Contrary to widespread assumptions in the literature, endozoochory by ducks appears to be a much more important mode of dispersal for aquatic plants than exozoochory. We found no evidence of changes in the probability of plant propagule dispersal at a landscape scale over the course of the winter, so propagule production and zoochory appear to be decoupled over time in aquatic systems.A.-L. Brochet is funded by a Doctoral grant from Office National de la Chasse et de la Faune Sauvage, with additional funding from a research agreement between ONCFS, the Tour du Valat, Laboratoire de Biométrie et de Biologie Evolutive (UMR 5558 CNRS Université Lyon 1) and the Doñana Biological Station (CSIC). This work also received funding from the Agence Nationale de la Recherche through the Santé Environnement – Santé Travail scheme (contract number 2006-SEST-22).Peer reviewe

Cartographie automatisée des zones à hauts risques naturels par superposition de données multivariées : exemple de la commune de Seillans (Var)

Mémoire HS n° 15 - Géologie Alpine Risques naturels dans le Sud-est de la France - Colloque Association des Géologues du Sud-est - Avignon, 19 et 20 octobre 1989Dans le cadre d'une étude financée par l'EPR PACA, nous avons développé une méthode de cartographie des zones soumises à des mouvements du sol, à l'aide de moyens infonnatiques. Nous avons appliqué cette méthode à la commune de Seillans afin d'intégrer cette carte des risques dans le plan d'occupation des sols. Parmi les phénomènes naturels qui contraignent l'utilisation du sol, nous n'avons pris en compte que le phénomène glissement de terrain : il n'est en effet pas encore possible par les méthodes employées de mettre en évidence les zones soumises à des phénomènes de dissolution; nous avons également laissé de coté le risque lié à l'instabilité des falaises et des chutes de blocs. Pour réaliser cette cartographie des zones soumises à des mouvements de sol, nous avons retenu trois facteurs: - nature lithologique des terrains affleurant, - pente topographique et sa valeur en pourcentage - hydrologi

Planification côtière en Afrique de l’Ouest. Retour d’expérience SIG en Guinée-Bissau

Cet article relate le contexte de la mise en œuvre d’un SIG à vocation de planification côtière en Guinée-Bissau dans le contexte de création d’une réserve de biosphère. Il fait le bilan des productions et des acquis de 10 ans de collaboration entre des organismes de recherche et de gestion territoriale du nord et du sud. Une expérience qui fait école au sein des pays côtiers d’Afrique de l’Ouest.This article reports the context of the implementation of a GIS which is intended for coastal planning in Guinea Bissau in the context of the creation of a biosphere reserve. It takes stock of the productions and the assets of 10 years of collaboration between research and territorial management organisations of the north and south. This experiment has become a model in the coastal countries of West Africa

Indeterminate status of West African populations of inshore common bottlenose dolphins <i>Tursiops truncatus</i> caution against opportunistic live-capture schemes

The limited information available on the status of inshore common bottlenose dolphins Tursiops truncatus along the coasts of West Africa is reviewed. Although reported from at least ten countries, it is unclear whether their distribution is continuous. Population structure and genetics have not been studied, however cranial morphology suggests that the West African dolphins differ from North Sea bottlenose dolphins. Mean group sizes are small (3.19 – 12.91 individuals/group) and are smallest in Guinea-Bissau. There are no estimates of abundance but by analogy with a well-studied population in Sarasota, Gulf of Mexico, the Guinea-Bissau population may number only in the hundreds. It is essential that scientific estimates be obtained through dedicated surveys. In some areas of Guinea-Bissau with a high density of fishing activities, bottlenose dolphins are now less frequently encountered than they were in the recent past. Key parameters besides abundance, including population identity, bycatch levels and other anthropogenic threats need to be documented and quantified before any deliberate exploitation is considered. A small-scale, botched live-capture operation in Senegal in 2003, in which all dolphins died, serves as warning against such opportunistic schemes. In management terms, live-capture operations are equivalent to hunting and multi-year, large-scale removals of bottlenose dolphins in Guinea-Bissau would have the potential to effectively extirpate the wild population from its waters