Le maerl algues corallinacées marines dans les Pertuis Charentais
La répartition du maerl, algues rouges marines Corallinacées à thalles calcifiés arbusculaires et non fixés, est évaluée dans les Pertuis charentais grâce à la compilation d’observations ponctuelles réalisées de 2006 à 2012 à la fois sur les fonds sédimentaires infralittoraux et en zone intertidale. Repéré initialement par des prélèvements à la benne en octobre 2009 lors de la validation de prospections sonar, un banc de maerl vif est cartographié en juillet 2011 en rade de Saint-Martin (Pertuis Breton). Sa superficie est estimée à plus de 2 km². Est confirmé l’unique relevé algologique de Phymatolithon calcareum fait au début du XXème siècle à Saint-Martin de Ré par Dollfus. De très nombreux thalles en voie de diagénèse ont aussi été observés dans l’Est et Sud-Est des Pertuis Breton et d’Antioche suggérant des apports par transports passifs issus de bancs vivants situés plus à l’Ouest. La présence de maerl vif sur le bas des estrans est en effet connue très ponctuellement dans l’Ouest des îles d’Oléron et de Ré. Sur le plan biogéographique, le banc de maerl du Pertuis Breton est le plus oriental et le plus méridional de ceux connus dans le Golfe de Gascogne, les plus proches étant situés à Noirmoutier (baie de Bourgneuf) et en Galice (Espagne). Nos observations complètent l’atlas cartographique de la convention OSPAR des populations de maerl en Europe et apportent une base de connaissances aux actions de conservation à définir localement dans le contexte Natura 2000 en mer.
(Annales de la Société des Sciences naturelles de Charente-Maritime. vol. 10, n° 0373-9929, pp. 281-300, 13/04/2026)
LIENSs, INSU - CNRS, ULR, CNRS, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MNHN, LERPC, COAST, IFREMER, LRHLR, HGS, IFREMER
Evaluation of tertiary treatments for the reduction of refractory micropollutants in wastewater
Some refractory micropollutants remain in treated wastewater after secondary treatments. In order to reduce their concentration in treated water, tertiary treatments can be used such as advanced oxidation processes and activated carbon. The efficiency of granular activated carbon in a long term is not well known and advanced oxidation processes have mostly been studied at laboratory scale. Advanced oxidation processes and granular activated carbon pilots were studied in two different wastewater treatment plants in order to determine their efficiency on numerous micropollutants. Both processes were efficient (>90%) on beta blockers and other drugs. The removal of alkylphenols was not complete with UV and hydrogen peroxide. Activated carbon was still efficient after six months functioning 24/24.
(pp. 3 p., 13/04/2026)
CIRSEE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Mobilities and spatiotemporal policies
(13/04/2026)
ESO, UNICAEN, NU, UM, UA, UR2, CNRS, IGARUN, UN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
7000 years of paleostorm activity in the NW Mediterranean Sea in response to Holocene climate events
A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300-6100, 5650-5400, 4400-4050, 3650-3200, 2800-2600, 1950-1400 and 400-50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150-650 cal yr BP) was characterised by low storm activity.;The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling-in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain. (C) 2011 University of Washington. Published by Elsevier Inc. All rights reserved.
(Quaternary Research. vol. 77, n° 0033-5894, pp. 1-11, 13/04/2026)
UAG, INSU - CNRS, UM, CNRS, EDYTEM, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, Géosciences Montpellier, UAG, INSU - CNRS, UM, CNRS, IDES, UP11, INSU - CNRS, CNRS, UAG, INSU - CNRS, UM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEOTRAC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Morphological anomalies in estuarine shrimp larvae
For several years, major exoskeletal anomalies in two species of European estuarine shrimp of the genus Palaemon have been observed. The phenomenon has been described for P. longirostris and P. macrodactylus in the Gironde estuary (France) and affects all stages of the species’ life cycles: from juvenile to adult and in both wild and laboratory-reared individuals. In the present follow-up study, the effects of these anomalies in larval stages of the two species were investigated. Regular sampling across most of the saline estuary confirmed that the post-larval stages of both species were affected. The morphological anomalies (MA) observed in the larvae were of the same type as those described for the adult stages, although more limited and primarily affecting the rostrum and cephalothorax. Larvae were reared from hatching to the post-larval stage, and the appearance of the aforementioned anomalies was observed as early as in Zoea I. This was the case even in larvae whose mothers did not exhibit anomalies. For both species, the most advanced stage was the one most affected. Also, in the rearing experiment, a greater proportion of the P. macrodactylus larvae was affected than those of P. longirostris. No significant effects ofMA on size or growth rate were demonstrated for larvae of either species in this study. Nevertheless, it provides data on larval growth that were not previously available. Further rearing experiments should be considered in order to explore any demonstrable effects of these morphological anomalies.
(Crustaceana. vol. 85, n° 0011-216X, pp. 11-25, 13/04/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Etude intégrée de l’effet des apports amont et locaux sur le fonctionnement de la Garonne estuarienne (ETIAGE) : Rapport année 1 Avril 2010 - Mars 2011 Addendum
Le programme ETIAGE a été mis en place avec pour objectif de répondre aux questions suivantes : que représentent les apports des effluents de la Communauté Urbaine de Bordeaux (CUB) par rapport à ceux venant de l’amont en termes de charge organique et de micro-polluants ? Quels rôles sur le devenir des effluents jouent la présence du bouchon vaseux et la stagnation résiduelle des eaux (déplacement net entre mouvement de flot et de jusant) au niveau de l’estuaire fluvial amont en période d’étiage estival ? Réciproquement, à quels moments et jusqu’où s’étend l’impact de ces effluents sur la qualité des eaux de la Garonne estuarienne ? Quelles incidences des effluents sur le comportement des populations biologiques en place ou migratoires dans la Garonne estuarienne ? Quelle tendance évolutive va connaître l’oxygénation des eaux ? Quel sera l’impact sur le comportement des micro-polluants et des populations biologiques ? Quelles recommandations de gestion pourraient être préconisées à partir de la synthèse des pressions exercées sur les eaux de la Garonne estuarienne ? Le programme est divisé en 5 axes, dont les bilans de travail sont présentés axe par axe pour l’année 1, couvrant la période Avril 2010 – Mars 2011. Cet addendum vient en complément du rapport exécutif, volontairement synthétique, présenté pour chacun des axes de recherche. Hormis les recherches menées dans l’axe 1, strictement débutées en Avril 2011, toutes les autres ont commencé avec plusieurs mois de retard (de trois à neuf mois), pour diverses raisons explicitées en introduction du rapport exécutif. Aussi, seuls des documents complémentaires concernant l’axe 1 seront-ils fournis pour cette première année.
(pp. 14, 13/04/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Towards the evaluation of ecological consequences of hydromorphological evolutions of the Gironde estuary: A preliminary approach combining GIS and hydrodynamics modelling
Estuaries are composed of a mosaic of habitat providing various ecological functions for many biological communities and many goods and services to society. At the interface between continents and oceans, estuaries in general, and particularly large estuaries, are also environments which concentrate important ecological issues but also many environmental climatic and anthropogenic pressures. The Gironde estuary, one of the largest European estuaries, is thus an emblematic case. Historically, it has undergone major evolutions of its hydromorphosedimentary characteristics due to impacts of climate change and human activities. The aim of this work is to assess the ecological consequences of these changes through the study of the evolution of surfaces of estuarine available habitats and the knowledge of ecological functions associated with these habitats. To do this, we propose to combine two approaches: ecological and hydromorphosedimentary. First, work was undertaken to determine, from scientific literature, tolerances and preferences of representative species of the ecosystem for each of the parameters determining estuarine aquatic habitats (depth, salinity, sedimentary facies ...). Thus, combining available map data and results from a hydrodynamic model implemented in the Gironde, we can map the spatial distribution of these species in the estuary using a geographic information system (GIS). Then, we characterized the ecological functions associated with each habitat (eg. nursery role for sole, migration for eels ...). On the other hand, old maps of the environment have been digitized and analysis was undertaken to characterize the evolution of morphology, hydrological and sedimentary dynamics of the estuary in recent decades. The potential distribution maps we obtained allowed defining a kind of ecological potential that can be used as a reference for assessing effects of development issues, management measures or climate change scenarios. Results highlighted small changes in functional habitats distributions but high vulnerability of some of them (nursery grounds).
(pp. 14, 13/04/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact écotoxicologiques et économiques des phénomènes de sous-oxygénation et de pollution des estuaires sur l'anguille européenne (Anguilla anguilla)?
(pp. 28, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFREMER, UR EPBX, IRSTEA, GREThA, UB, CNRS
A two-step process for the reflooding of the Mediterranean after the Messinian Salinity Crisis
The Messinian Salinity Crisis is well known to have resulted from a significant drop of the Mediterranean sea level. Considering both onshore and offshore observations, the subsequent reflooding is generally thought to have been very sudden. We present here offshore seismic evidence from the Gulf of Lions and re-visited onshore data from Italy and Turkey that lead to a new concept of a two-step reflooding of the Mediterranean Basin after the Messinian Salinity Crisis. The refilling was first moderate and relatively slow accompanied by transgressive ravinement, and later on very rapid, preserving the subaerial Messinian Erosional Surface. The amplitude of these two successive rises of sea level has been estimated at ≤500 m for the first rise and 600-900 m for the second rise. Evaporites from the central Mediterranean basins appear to have been deposited principally at the beginning of the first step of reflooding. After the second step, which preceeded the Zanclean Global Stratotype Section and Point, successive connections with the Paratethyan Dacic Basin, then the Adriatic foredeep, and finally the Euxinian Basin occurred, as a consequence of the continued global rise in sea level. A complex morphology with sills and sub-basins led to diachronous events such as the so-called 'Lago Mare'.This study helps to distinguish events that were synchronous over the entire Mediterranean realm, such as the two-step reflooding, from those that were more local and diachronous. In addition, the shoreline that marks the transition between these two steps of reflooding in the Provence Basin provides a remarkable palaeogeographical marker for subsidence studies.
(Basin Research. vol. 24, n° 0950-091X, pp. 125-153, 13/04/2026)
iSTeP, UPMC, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS, LDO, INSU - CNRS, UBO EPE, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, GM, IFREMER, IDES, UP11, INSU - CNRS, CNRS, GeoEcoMar, ICM, CSIC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISTO, INSU - CNRS, UO, UT, CNRS, UERJ, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, UKIM, BAS, GEOLOGY AND MINING DEPARTMENT, ITÜ, VU, ITÜ, GR, UR, INSU - CNRS, CNRS
Factors influencing the stable carbon isotopic composition of suspended and sinking organic matter in the coastal Antarctic sea ice environment
A high resolution time-series analysis of stable carbon isotopic signatures in particulate organic carbon (δ 13 C POC) and associated biogeochemical parameters in sea ice and surface waters provides an insight into the factors affecting δ 13 C POC in the coastal western Antarctic Peninsula sea ice environment. The study covers two austral summer seasons in Ryder Bay, northern Marguerite Bay between 2004 and 2006. A shift in diatom species composition during the 2005/06 summer bloom to near-complete biomass dominance of Proboscia inermis is strongly correlated with a large ∼10 ‰ negative isotopic shift in δ 13 C POC that cannot be explained by a concurrent change in concentration or isotopic signature of CO 2. We hypothesise that the δ 13 C POC shift may be driven by the contrasting biochemical mechanisms and utilisation of carbon-concentrating mechanisms (CCMs) in different diatom species. Specifically, very low δ 13 C POC in P. inermis may be caused by the lack of a CCM, whilst some diatom species abundant at times of higher δ 13 C POC may employ CCMs. These short-lived yet pronounced negative δ 13 C POC excursions drive a 4 ‰ decrease in the seasonal average δ 13 C POC signal, which is transferred to sediment traps and core-top sediments and consequently has the potential for preservation in the sedimentary record. This 4 ‰ difference between seasons of contrasting sea ice conditions and upper water column stratification matches the full amplitude of glacial-interglacial Southern Ocean δ 13 C POC variability and, as such, we invoke phytoplankton species changes as a potentially important factor influencing sedi-mentary δ 13 C POC. We also find significantly higher δ 13 C POC in sea ice than surface waters, consistent with autotrophic carbon fixation in a semi-closed environment and possible contributions from post-production degradation, biological utilisation of HCO − 3 and production of exopolymeric substances. This study demonstrates the importance of surface water diatom speciation effects and isotopically heavy sea ice-derived material for δ 13 C POC in Antarctic coastal environments and underlying sediments, with consequences for the utility of diatom-based δ 13 C POC in the sedimentary record.
(Biogeosciences. vol. 9, n° 1726-4170, pp. 1137-1157, 13/04/2026)
UEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BAS, NERC