La colonisation des parcs d'énergies marines renouvelables facilite-t-elle l'introduction et la propagation d'espèces non indigènes ?
(Bulletin COME3T, n° 2743-6896, pp. 12, 01/12/2019)
FEM, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], ULCO, LBCM, UBS, UBO EPE, IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, CNRS, IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MMS, UM, UN UFR ST, UN, UFR SPB, UN, BIOSSE, UCO, LEMAR, IRD, IFREMER, UBO EPE, CNRS, PatriNat, MNHN, CNRS, AFB
Nature-Based Solution along High-Energy Eroding Sandy Coasts: Preliminary Tests on the Reinstatement of Natural Dynamics in Reprofiled Coastal Dunes
This paper describes a large-scale experiment designed to examine if reinstating natural processes in the coastal dune systems of Southwest France can be a relevant nature-based adaptation in chronically eroding sectors and a nature-based solution against coastal hazards, by maintaining the coastal dune ecological corridor. An experiment started in late 2017 on a 4-km-long stretch of coast at Truc Vert, where experimental notches were excavated and intensively monitored in the incipient and established foredunes. Preliminary results indicate that most of the excavated notches did not develop into blowout. Only the larger elongated notches subsequently excavated in the established foredune in 2018 showed evidence of development, acting as an effective conduit for aeolian landward transport into the dunes. All notches were found to have a statistically significant impact on vegetation dynamics downwind, even those that did not develop. The area of bare sand landward and within the elongated notches notably increased implying a loss of vegetation cover during this first stage of development. Observations of a nearby coastal dune system that has been in free evolution over the last 40 years also indicate that, although the dune migrated inland by more than 100 m, it is now mostly made of bare sand. Further work is required to explore if and how dunes maintained as dynamic systems can become an efficient nature-based solution along this eroding coastline.
(Water. vol. 11, n° 2073-4441, pp. 2518, 28/11/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ONF, INCM, CNRS, IPR, UR, CNRS, LGCGM, UR, INSA Rennes, INSA, LTeN, EPUN, UN, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS
Alongshore variability in crescentic sandbar patterns at a strongly curved coast
(Journal of Geophysical Research: Earth Surface. vol. 124, n° 2169-9003, pp. 2877– 2898, 23/11/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Une chronologie étendue des crues de la Garonne entre ca. 500 et 1500 AD. : apports croisés et comparés des sources historiques et sédimentaires
(21/11/2019)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBM, CNRS, LASCARBX, UB, UBM, GEODE, UT2J, Comue de Toulouse, CNRS
A drop does not fall in a straight line: a rationale for the width of stalagmites
(Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. vol. 475, n° 1364-5021, pp. 20190556, 20/11/2019)
IS2M, Université de Haute-Alsace (UHA), INC-CNRS, CNRS, MNGE, UNISTRA, Université de Haute-Alsace (UHA), INSERM, INC-CNRS, CNRS, UNISTRA, Université de Haute-Alsace (UHA), CNRS, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BRGM
Comparing the efficiency of hypoxia mitigation strategies in an urban, turbid tidal river via a coupled hydro-sedimentary-biogeochemical model
Coastal-water hypoxia is increasing globallydue to global warming and urbanization, and the need todefine management solutions to improve the water quality ofcoastal ecosystems has become important. The lower tidalGaronne River (TGR; southwestern France), characterizedby the seasonal presence of a turbidity maximum zone(TMZ) and urban water discharge, is subject to episodichypoxia events during low river flow periods in the summer.Future climatic conditions (higher temperature and summerdroughts) and increasing urbanization could enhance hy-poxia risks near the city of Bordeaux in the coming decades.A 3-D model of dissolved oxygen (DO) that coupleshydrodynamics, sediment transport and biogeochemicalprocesses was used to assess the efficiency of differentmanagement solutions for oxygenation of the TGR duringsummer low-discharge periods. We ran different scenarios ofreductions in urban sewage overflows, displacement of urbandischarges downstream from Bordeaux and/or temporaryriver flow support during the summer period. The modelshows that each option mitigates hypoxia, but with variableefficiency over time and space. Sewage overflow reductionimproves DO levels only locally near the city of Bordeaux.Downstream relocation of wastewater discharges allows forbetter oxygenation levels in the lower TGR. The support ofow river flow limits the upstream TMZ propagation anddilutes the TGR water with well-oxygenated river water.Scenarios combining wastewater network management andlow-water replenishment indicate an improvement in waterquality over the entire TGR. These modelling outcomesconstitute important tools for local water authorities todevelop the most appropriate strategies to limit hypoxia inthe TGR.
(Natural Hazards and Earth System Sciences. vol. 19, n° 1561-8633, pp. 2551-2564, 19/11/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EDF [E.D.F.], BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA
Detection of adsorbed chlordecone on microplastics in marine sediments in Guadeloupe: a preliminary study
Plastic pollution in the oceans is recognized as a worldwide problem. Since the 1950s, the production of plastics has been increasing and the first reports of microplastics (particles < 500 μm) in the marine environment began to appear in the 1970s. These particles represent a growing environmental problem due to their dispersion in seawater and marine organisms. Additionally, microparticles in general can adsorb pollutants that will then become bioavailable to organisms by being desorbed during digestion, which could be an important pathway for the contamination of organisms. In Guadeloupe and Martinique, an organochlorine pesticide called “chlordecone” was used from 1972 to 1993 in banana plantations and this very persistent pollutant contaminates soils, rivers, and coastal marine areas and accumulates in marine foodwebs. To examine these issues, we had two goals: 1) to assess the contamination of marine sediments by microplastics surrounding Guadeloupe; and 2) to determine the ability of microplastics to adsorb chlordecone, as has been demonstrated for other organochlorine pollutants. To do so, marine sediments were collected in triplicate from 12 sites in coral reef environments around the island. Microplastics from each sample were then enumerated by size, color and shape under a binocular microscope. The results indicate that microplastics are found in all the studied sites and that their distribution could be linked to marine currents or proximity to areas of significant human activities (port activities, agglomeration, etc.). Finally, our preliminary results indicated that chlordecone could be adsorbed onto microplastics, with a concentration ranging from 0.00036—0.00173 µg/µg of microfilter.
(Gulf and Caribbean Research. vol. 30, n° 1528-0470, pp. GCFI 8-GCFI 14, 13/11/2019)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Vers des traitements des eaux usées plus durables : Prise en considération des Produits de Transformation des contaminants chimiques organiques - TRANSPRO
La préservation de la qualité de l'eau est un enjeu majeur à la fois pour l'environnement et pour la santé humaine. Dans le contexte de la Directive Cadre sur l'Eau (DCE, 2000/60/CE), de nombreux travaux ont étudié les micropolluants organiques, et les connaissances concernant leur présence, voies d'introduction, sources et impacts sur les écosystèmes aquatiques ont considérablement augmenté. Les eaux usées étant des sources importantes de micropolluants en lien avec la consommation de produits manufacturés, l'application de la DCE a conduit au renforcement de la réglementation sur le traitement des eaux usées urbaines et à la généralisation des procédés biologiques tels que les boues activées à aération prolongée ou les biofiltres, permettant d'éliminer significativement les micropolluants organiques. Les processus d'oxydation impliqués consistent en une dégradation qui peut ne pas être complète, générant des produits de transformation (TP) relativement stables et toxiques susceptibles de se retrouver à la fois dans les boues et effluents liquides. Jusqu'à présent, les données sur les TP restent rares et se limitent à quelques composés. Ainsi, il apparaît essentiel que les futurs projets de recherche portent sur la question des TP afin d'élucider leur présence, formation et devenir tout au long du système de traitement des eaux usées jusqu'à leur entrée potentielle dans le milieu aquatique par le biais des rejets d'effluents des stations d'épuration (STEP). Objet ou objectifs TRANSPRO étudie la formation des TP, en développant des méthodes innovantes de screening utilisant des outils à la fois chimiques (Spectrométrie de Masse Haute Résolution) et biologiques (tests in vitro). Il étudie l'ensemble du système de traitement des eaux usées (des entrées de STEP) jusqu'aux écosystèmes aquatiques naturels, en se concentrant sur différents types de procédés de traitement par rapport à leur capacité à générer des TP ainsi que sur les procédés naturels (biodégradation, photo-oxydation) pouvant donner lieu à des transformations dans le milieu lui-même. Méthode TRANSPRO est un projet financé par l'agence nationale de la recherche (ANR) sur la période 2019-2022. Il est porté par un consortium de partenaires publics. C'est un projet collaboratif impliquant un partenariat solide basé sur une expertise pluridisciplinaire, associant chimistes analyticiens (EPOC), physico-chimistes (EPOC, LGC), chimistes de l'environnement (EPOC, Irstea), spécialistes en génie des procédés et modélisation (Irstea, LGC), (éco) toxicologues (EPOC), spécialistes des systèmes de traitement des eaux usées (LGC, Irstea), tous rassemblés pour aborder une question commune: quels processus génèrent des TP, que sont ces TP et quels sont ceux pertinents d'un point de vue environnemental ? Résultats TRANSPRO va permettre d'améliorer nos connaissances sur la nature, l'origine et la dynamique des TP. Il permettra également de classifier les procédés de traitement des eaux usées par rapport à leur tendance à générer des TP et d'aider à sélectionner le processus le plus efficace en termes de dégradation des contaminants parents mais minimisant la formation des TP. TRANSPRO fournira ainsi des connaissances qui contribueront à améliorer les traitements des eaux usées pour concevoir les systèmes d'assainissement de demain. Tout savoir sur le projet TRANSPRO : https://lnkd.in/dkZnUyS
(pp. 1, 07/11/2019)
UR REVERSAAL, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LGC, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, IUT Toulouse Auch Castres, UT3, Comue de Toulouse
Chemical Heterogeneity of Mg, Mn, Na, S, and Sr in Benthic Foraminiferal Calcite
The chemical composition of fossil foraminiferal shells (tests) is widely used as tracers for past ocean chemistry. It is, therefore, important to understand how different (trace) elements are transported and incorporated into these tests from adjacent seawater. The elemental distribution within the walls of foraminiferal tests might be used to differentiate between proposed transport mechanisms. Here, the microdistribution of Mg, Mn, Na, S, and Sr in tests of three species of foraminifera, known to have contrasting test chemistry, is investigated by a combination of electron probe microanalysis (EPMA) and nanoscale secondary ion mass spectrometry (nanoSIMS), micro-X-ray fluorescence (µXRF), and micro-X-ray absorption near-edge structure (µXANES) analyses. The three investigated species are the symbiont-barren Ammonia sp. T6 and Bulimina marginata, which precipitate a low-Mg calcite test, and the symbiont-bearing species Amphistegina lessonii, which produces a test with intermediate Mg content. Because all analyzed tests were formed under controlled and identical laboratory conditions, the observed distributions of elements are not due to environmental variability but are a direct consequence of the processes involved in calcification or, in the case of A. lessonii, possibly symbiont activity. Despite some variability in elemental microdistribution between specimens from a given species, our combined dataset shows species-specific distributions of the elements (e.g., peak heights and/or band-widths) and also a systematic colocation of Mg, Na, S, and Sr for all three species, suggesting a coupled or simultaneous uptake, transport, and incorporation of these elements during chamber addition. The observed trace element patterns generally reflect a laminar calcification model, suggesting that heterogeneity of these elements is intrinsically linked to chamber addition. Although the incorporation of redox-sensitive Mn depends on the Mn concentration of the culture medium, the Mn distribution observed in Ammonia sp. suggests that Mn transport is similarly linked to laminar calcification dynamics. However, for B. marginata, Mn banding was sometimes anticorrelated with Mg banding, suggesting that (bio)availability, uptake, and transport of Mn differ from those forAmmonia sp. Our results from symbiont-bearing A. lessonii suggest that the activity of symbionts (i.e., photosynthesis/respiration) may influence the incorporation of Mn owing to alternation of the chemistry in the microenvironment of the foraminifera, an iimportant consideration in the development of this potential proxy for past oxygenation of the oceans.
(Frontiers in Earth Science. vol. 1, n° 2296-6463, 07/11/2019)
LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ESRF, LAMS, UPMC, INC-CNRS, SU, CNRS, UACH
Seasonal influence of parasitism on contamination patterns of the mud shrimp Upogebia cf. pusilla in an area of low pollution
(Science of the Total Environment. vol. 692, n° 0048-9697, pp. 319-332, 01/11/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS