25 research outputs found

    Expressions biogéologiques du confinement dans une lagune méditerranéenne : le lac Melah (Algérie)

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    Le lac Melah est un bassin paralique relativement profond communiquant avec la mer par un chenal étroit de faible profondeur. Ces caractéristiques ont pour conséquences la stratification des eaux et un fort confinement de l'ensemble du bassin qui engendre une biomasse phytoplanctonique élevée. Celle-ci est peu consommée par une macrofaune dense mais de faible biomasse et se dépose massivement sous la lentille d'eau inférieure anoxique. Le lac Melah apparaßt ainsi comme un modÚle actuel de bassin producteur de roches-mÚres d'hydrocarbures. En revanche, ses potentialités aquacoles sont limitées. (Résumé d'auteur

    TRY plant trait database – enhanced coverage and open access

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    Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Zika virus infection in pregnancy: a protocol for the joint analysis of the prospective cohort studies of the ZIKAlliance, ZikaPLAN and ZIKAction consortia

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    INTRODUCTION: Zika virus (ZIKV) infection in pregnancy has been associated with microcephaly and severe neurological damage to the fetus. Our aim is to document the risks of adverse pregnancy and birth outcomes and the prevalence of laboratory markers of congenital infection in deliveries to women experiencing ZIKV infection during pregnancy, using data from European Commission-funded prospective cohort studies in 20 centres in 11 countries across Latin America and the Caribbean. METHODS AND ANALYSIS: We will carry out a centre-by-centre analysis of the risks of adverse pregnancy and birth outcomes, comparing women with confirmed and suspected ZIKV infection in pregnancy to those with no evidence of infection in pregnancy. We will document the proportion of deliveries in which laboratory markers of congenital infection were present. Finally, we will investigate the associations of trimester of maternal infection in pregnancy, presence or absence of maternal symptoms of acute ZIKV infection and previous flavivirus infections with adverse outcomes and with markers of congenital infection. Centre-specific estimates will be pooled using a two-stage approach. ETHICS AND DISSEMINATION: Ethical approval was obtained at each centre. Findings will be presented at international conferences and published in peer-reviewed open access journals and discussed with local public health officials and representatives of the national Ministries of Health, Pan American Health Organization and WHO involved with ZIKV prevention and control activities

    La recherche scientifique face Ă  la pĂȘche artisanale = Research and small-scale fisheries

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    The methods of quantifying fishing activity in the coastal lagoons of Languedoc using three indicators (number of fishing nets, boats and fishermen) are presented and compared. In practice, aerial counts of fishing nets is the only method which can be used on a regional scale; errors are variable but never exceed 10%. Although counts by indirect observations (photo-video) are more precise, they are still too expensive to be applied to routine surveys. the visualization of the nets is improved by optical filters (with black and white infra-redfilms). For smaller lagoons, it is cheaper to count fishermen, but the relationship between this indicator and the number of nets is not constant.(Résumé d'auteur

    Diagnose Ă©cologique en vue de la gestion d'un milieu naturel : secteur du domaine de la Palissade (Bouches du RhĂŽne)

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    [Notes_IRSTEA]graph., tabl., bibl.Définition d'un programme de mise en valeur aquacole du secteur du domaine de la Palissade et du Grau du Piemanson. La démarche utilisée repose sur une caractérisation écologique préalable du milieu puis sur une méthode de planification qui confronte l'offre du milieu (défini par l'étude écologique) et la demande sociale exprimée (mise en valeur aquacole). Les bases d'application de ces deux méthodes sont expliquées dans le chapßtre I. Les éléments qui la composent sont détaillés dans le chapßtre II. Le dernier chapßtre porte sur la définition des potentialités aquacoles et l'analyse des modalités pratiques d'application

    Mise au point d'un trieur Ă  anguilles

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    Les auteurs ont cherché à développer une stratégie d'échantillonnage stratifiée, méthode de travail qui permet une étude de toutes les catégories d'anguilles, indépendamment de leur rareté, tout en conservant une mesure de leur importance par rapport au reste de la population. Pour ce faire, un trieur à anguilles qui décompose les échantillons en strates a été réalisé

    Suivi hydrobiologique d'une lagune amenagee pour l'aquaculture

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    Job number added acc. to DOCREP assignmen

    L'étang de Terrenzana (Haute Corse) : caractérisation écologique du site en vue de sa gestion

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    [Notes_IRSTEA]tabl., fig.Cette Ă©tude porte sur l'Ă©tang de Terrenzana en Corse. Elle use Ă  caractĂ©riser l'Ă©tat actuel du site, Ă  en dĂ©fini les potentialitĂ©s et les modalitĂ©s de gestion envisageables. Ce rapport rĂ©sulte d'une campagne de terrain et d'une enquĂȘte aupres des divers intervenants menĂ©es en 1986 par le CEMAGREF. Une comparaison rapide avec l'Ă©tang de Santa Giulia a Ă©tĂ© rĂ©alisĂ©e
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