Environmental management and water quality: The case of the Médoc lakes territory
The SIAEBVELG intervenes on the 1000 km² of the Medoc Lakes watershed. It exercises the GEMAPI competence, runs the SAGE and the Natura 2000 sites linked to the lakes. The issues of water quality for the Medoc Lakes are important with the problems of eutrophication and recreational tourism. Regulatory monitoring is carried out, but it is insufficient to understand the functioning of a lake and its watershed. Research work has made it possible to draw up a complete mass balance of nutrients (N, P and Si) and water on the scale of the catchment area of the Medoc lakes. These studies required a sampling of all the compartments that affect the lake ecosystem: the watershed (groundwater and surface water), rainwater, sediments, the lake water column and wetlands. Sediment mapping allowed us for the first time to quantify fluxes at the water-sediment interface. Results shows that nitrogen fluxes are mainly related to agricultural inputs from the Carcans-Hourtin Lake watershed. Phosphorus inputs are low. The biological production of the lakes is limited by this nutrient. The lakes play a buffer role in the watershed-lake-Basin d'Arcachon continuum, since they retain more than 60% of the nutrients in the form of organic and mineral particles stored in the sediment. This retention capacity is not infinite. Efforts to continue limiting inflows are necessary, particularly in a context of global warming. Based on this observation, an approach has been set up in order to reduce nitrogen inputs and monitor phosphorus flows. It is taking the form of improved agricultural practices, the establishment of constructed wetlands and the restoration of natural wetlands.
(Dynamiques Environnementales - Journal international des géosciences et de l’environnement, n° 1968-469X, pp. 124-152, 06/10/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBM
Monitoring Beach Topography and Nearshore Bathymetry Using Spaceborne Remote Sensing: A Review
With high anthropogenic pressure and the effects of climate change (e.g., sea level rise) on coastal regions, there is a greater need for accurate and up-to-date information about the topography of these systems. Reliable topography and bathymetry information are fundamental parameters for modelling the morpho-hydrodynamics of coastal areas, for flood forecasting, and for coastal management. Traditional methods such as ground, ship-borne, and airborne surveys suffer from limited spatial coverage and temporal sampling due to logistical constraints and high costs which limit their ability to provide the needed information. The recent advancements of spaceborne remote sensing techniques, along with their ability to acquire data over large spatial areas and to provide high frequency temporal monitoring, has made them very attractive for topography and bathymetry mapping. In this review, we present an overview of the current state of spaceborne-based remote sensing techniques used to estimate the topography and bathymetry of beaches, intertidal, and nearshore areas. We also provide some insights about the potential of these techniques when using data provided by new and future satellite missions.
(Remote Sensing. vol. 11, n° 2072-4292, pp. 2212, 01/10/2019)
M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, IUP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM, LOMC, ULH, NU, CNRS
Impact of chemical pollution on Atlantic eels: Facts, research needs, and implications for management
(Current Opinion in Environmental Science & Health. vol. 11, pp. 26-36, 01/10/2019)
INBO, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Natural regeneration of Pinus brutia Ten. in a recreational public forest in Zawita-Kurdistan region, Iraq
Zawita natural forest has recently has been subject to mass recreational activities during spring that have denuded large areas of the forest. It was thus essential to assess regeneration before designing optimizing strategies. To this end, we studied the overstory canopy and microhabitat conditions for recruitment of Pinus brutia Ten in 10 plots (20 × 25 m) on the southern aspects where the Zawita natural forest is still present. In total, 1540 regenerating P. brutia were recorded, 854 seedlings, 597 saplings, and 89 trees. Seedlings and saplings were more frequent beyond the canopy than under the canopy of the parent trees. Regeneration requirements differed between seedlings and saplings. The probability of the occurrence of seedlings was negatively correlated with increasing litter depth and increasing soil compaction. The density of saplings only showed a positive significant correlation with increasing slope. The nearest neighbor index showed a trend toward a positive spatial association between understory shrubs with their neighboring seedlings at a mean distance of 1.6 m. Overall, the study highlighted the requirements for seedling regeneration as a relatively open canopy cover, a light understory litter layer, and non-compacted soils. These results are a step towards designing effective management and restoration programs.
(Journal of Forestry Research. vol. 30, n° 1007-662X, pp. 1849-1857, 01/10/2019)
UMR AMAP, Cirad, INRA, UM, CNRS, IRD [Occitanie], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Local changes in copepod composition and diversity in two coastal systems of Western Europe
While long-term monitoring is essential to improve our knowledge of marine ecosystems health, it remains challenging to summarise complex ecological data in order to characterise and understand biodiversity trends. To compile monitoring data across large numbers of species, scientists and policymakers mainly rely on diversity and species richness indices. This task may prove complicated however, as many indices exist and no individual metric undoubtedly emerges as the best overall. Here, using data from zooplankton surveys from 1998 to 2014, we examined year-to-year changes in copepod communities in two littoral ecosystems of Western Europe - the Arcachon Bay and the Gironde estuary - that share similar climate, but with different local ecological processes, especially hydrological conditions. We tested the ability of commonly used α and β-diversity metrics, such as species richness, Pielou's evenness or Jaccard's index, to mirror year-to-year changes in species abundances and we detected a synchronous change in both copepod abundances and α-diversity that took place circa 2005 in the two sites. In response to changes in environmental conditions such as nutrients, salinity, river discharge or particulate matter, two opposite biodiversity trends were observed, with a decrease in copepod diversity in the Arcachon Bay but an increase in the downstream part of the Gironde estuary. Although diversity metrics allowed us to well detect trends, the use of multivariate approaches such as principal component analysis provided important information on how and why diversity fluctuates. Our study provides evidence that long-term monitoring programmes must be encouraged for optimising management and conservation actions such as the Marine Strategy Framework Directive and that more local comparative studies need to be initiated for better characterising diversity trajectories at very fine scales at which ecologists often work.
(Estuarine, Coastal and Shelf Science. vol. 227, n° 0272-7714, pp. 106304, 01/10/2019)
Evo-Eco-Paléo (EEP), CNRS, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Late Pleistocene oceanographic and depositional variations along the Wilkes Land margin (East Antarctica) reconstructed with geochemical proxies in deep-sea sediments
(Global and Planetary Change, n° 0921-8181, pp. 103045, 01/10/2019)
JAMSTEC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INGV
Le couple CoreBook / Cyber-Carothèque Nationale : un système de collecte et de gestion d’information dédié aux carottes sédimentaires marines et continentales.
La gestion des données constitue l’un des défis de l’Open science dans le contexte de la loi « Pour une république numérique ». Ceci est particulièrement important dans le domaine des sciences de la Terre et de l’environnement dans lequel la multiplication des échantillons de terrain et de mesures qui sont réalisées sur chaque conduit à une croissance exponentielle du nombre de données. Dans le cas de l’étude des carottes sédimentaires, l’engouement pour les méthodes paléoenvironnementales, pour répondre à des problématiques variées allant des chroniques de contaminations récentes aux évolutions climatiques pluriséculaires à plurimillénaire, voire plus, participe de cette croissance. Or, l’absence de systèmes d’information dédiée ne permet pas de capitaliser sur cette grande richesse en reliant les données entre elles.Dans cette contribution, nous présentons un système développé dans le cadre du programme Equipex CLIMCOR afin de bancariser les informations de terrain collectées lors du prélèvement de carottes sédimentaire. Ce système est constitué de deux modules : i) CoreBook, qui est une application mobile de collecte d’information sous Android et ii) la Cyber-carothèque nationale (Base MySQL), qui est un portail d’import, de consultation et de diffusion des informations.CoreBook a été pensé pour être embarquée sur une tablette durcie du commerce. Elle apporte une plus-value lors des opérations de carottage sur le terrain. Il comprend notamment des fonctionnalités comme le repérage des carottages précédents, une aide à la navigation et aux opérations d’ancrage ou encore la visualisation en coupe des carottages multi-sections et/ou multi-trous, ou en carte des carottages simple section. Optimisé pour la carottage multi-sections multi-séquences, il est adapté à tout type de méthode de carottage (carottier russe, gravitaire, piston stationnaire, etc.). Chaque entité de recherche (labo) a la possibilité de créer des configurations de matériels dans le portail « Cyber-carothèque » en constituant un référentiel qu’il retrouvera dans le CoreBook ; ce référentiel facilite la sélection d’outils une fois sur le terrain et associe automatiquement les paramètres de carottage et d’outils aux futurs échantillons ce qui permet de gagner en précision et qualité. Les données collectées par CoreBook sont directement synchronisables avec la cyber-carothèque. Un format d’échange permettra également d’alimenter les bases de données locales de laboratoire. La cyber-carothèque permet de gérer les configurations matérielles des entités de recherche. Elle recueille les métadonnées des opérations de prélèvement de carottes, soit via CoreBook, soit via un fichier d’import respectant un format spécifique. Interopérable, elle est capable, via des web-services, de moissonner des bases existantes et d’être moissonnée par celles-ci par des protocoles standardisés (OGC WFS).Une fois entrée dans la Cyber-carothèque, chaque échantillon reçoit un identifiant unique au format international IGSN. Equivalent d’un DOI pour les échantillons géologiques, cet identifiant permet de tracer la carotte et les opérations de terrain ayant permis de la prélever, à chaque fois qu’elle est utilisée pour une publication ou intégrée dans un système d’information. Il s’agit d’une étape préalable indispensable vers la bancarisation, la qualité, le partage et la réutilisabilité des données.Pour l’utilisateur final, la Cyber-carothèque offre des fonctionnalités de recherche et constitue une base de référence, structurée, ouverte et standardisé permettant de connaître les échantillons déjà prélevés dans une région donnée, ou encore de suivre l’activité d’un groupe de chercheur ou d’une entité de recherche. En prenant le problème de la gestion des données à la base, au niveau des opérations de terrain, le système CoreBook & Cyber-carothèque fournit à la communauté scientifique nationale un socle solide pour développer des bases de données, soit pour la gestion interne des données et/ou des échantillons, soit pour évoluer vers des systèmes plus intégrés en associant de données analytiques. La Cyber-carothèque est accessible à l’adresse : https://cybercarotheque.fr/index.php, on y trouve notamment le lien et les instructions pour télécharger l’application CoreBook.
(01/10/2019)
EDYTEM, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, DTI, INSU - CNRS, CNRS, INSU - CNRS
Fractionation of inherited and spiked antimony (Sb) in fluvial/estuarine bulk sediments: Unexpected anomalies in parallel selective extraction protocols
(Applied Geochemistry. vol. 108, n° 0883-2927, pp. 104386, 30/09/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Contribution of high resolution spatial remote sensing for the study of surface water cycles and suspended particulate matter along the watershed-coastal ocean continuum
The anticipation and adaptation of our societies to the upheavals resulting from climate change are today major issues guiding human activities and public action. Nevertheless, the forecast remains a key challenge because of the strong uncertainties that exist and it is essential to continue to progress in understanding the mechanisms behind these upheavals. Within the hydrological cycle, the surface reservoir (including lakes, rivers and floodplains) occupies an important place as it is one of the main water resources of ecosystems and populations. However, the dynamics of surface water stocks are still poorly known at the regional and global scales, due to the absence of multi-year measures of extension and water depth of the flooded areas, and the limited consideration of these variables in hydrological and hydrodynamic models. Satellite remote sensing now offers the possibility of monitoring surface water stocks by using the complementarity between multispectral imagery, allowing to map flooded areas, and the radar altimetry providing time series of water depths of continental hydro systems. The aim of my thesis is to make the most of the complementarity between the different types of spatial observations to evaluate the water resources of the surface reservoir and to measure the dynamics of water transfers between land and ocean, and its impact on the coastal zone using suspended particulate matter as tracer of water bodies. Since the mid-1990s, the multiplication of multispectral missions with medium resolution (<1 km of spatial resolution) and high-precision radar altimeters (between 10 and 30 cm) makes it possible to carry out weekly-to-monthly monitoring of volumes surface water in large river basins.
(17/09/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Microplastic contamination of sediment and water column in the Seine River Estuary
Nowadays, microplastic (MPs) pollution is well documented in marine ecosystems since the first publication alarming about marine plastic pollution in 1972 [1]. Similarly, continental contamination is more and more investigated. More recently, interest for estuarine systems is growing. Estuaries are considered as a suspected predominant pathway for microplastic pollution from continent to oceans. The specific conditions of estuaries, like salinity gradient, tides and hydrodynamics, could affect the repartition, settling and transfer of microplastics to marine systems.
(pp. p. 4-9, 16/09/2019)
LEESU, ENPC, UPEC UP12, IFREMER, LERN, COAST, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS