Deglacial and Holocene vegetation and climatic changes at the southernmost tip of the Central Mediterranean from a direct land-sea correlation
Despite a large number of studies, the long-term and millennial to centennial-scale climatic variability in the Mediterranean region during the last deglaciation and the Holocene is still debated, in particular in the Southern Central Mediterranean. In this 5 paper, we present a new marine pollen sequence (MD04-2797CQ) from the SiculoTunisian Strait documenting the regional vegetation and climatic changes in the Southern Central Mediterranean during the last deglaciation and the Holocene. The MD04-2797CQ marine pollen sequence shows that semi-desert plants dominated the vegetal cover in the Southern Central Mediterranean between 18 and 10 12.3 kyr BP indicating prevailing dry conditions during the deglaciation, even during the Greenland Interstadial (GI)-1. Such arid conditions likely restricted the expansion of the trees and shrubs despite the GI-1 climatic amelioration. Across the transition Greenland Stadial (GS)-1 – Holocene, Asteraceae-Poaceae steppe became dominant till 10.1 kyr. This record underlines with no chronological ambiguity that even 15 though temperatures increased, deficiency in moisture availability persisted into the Early Holocene.Temperate trees and shrubs with heaths as oak forest understorey or heath maquis expanded between 10.1 and 6.6 kyr, while Mediterranean plants only developed from 6.6 kyr onwards. These changes in vegetal cover show that the regional climate in Southern Central Mediterranean was wetter during Sapropel 1 (S1) 20 and became drier during the Mid- to Late Holocene. Wetter conditions during S1 were likely due to increased winter precipitation while summers remained dry. We suggest, in agreement with published modelling experiments, that the increased melting of the Laurentide Ice Sheet between 10 to 6.8 kyr in conjunction with weak winter insolation played a major role in the development of winter precipitation maxima in the Mediter25 ranean region in controlling the strength and position of the North Atlantic storm track. Finally, our data provide evidences of centennial-scale vegetation and climatic changes in the Southern Central Mediterranean. During the wet Early Holocene, alkenones-derived cooling episodes are synchronous to herbaceous composition changes that indicate muted changes in precipitation. In contrast, enhanced aridity episodes, as detected by strong reduction in trees and shrubs, are recorded during the Mid- to Late Holocene. We show that the impact of the Holocene cooling events depend on the baseline climate states insolation and ice sheet volume, shaping the response of the mid-latitude atmospheric circulation.
(pp. 5687–5741, 12/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, LCE, CNRS, UFC, UBFC, IDES, UP11, INSU - CNRS, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France]
Effect of trematode parasites on cockle Cerastoderma edule growth and condition index: a transplant experiment
We quantified the effect of trematode parasites in cockles through a 303 d transplant experiment. Cockles were sampled in 3 different sites on the southwest coast of France characterized by 3 different trematode communities, i.e. Royan (RO): high Meiogymnophallus minutus abundance near cockle heart, South Arguin (SA): high Himasthla interrupta abundance in the mantle margin, and North Arguin (NA): almost free of trematodes. Sampled cockles were individually tagged and placed in different cages at Banc d’Arguin, Arcachon Bay. At the end of the experiment, RO cockles had lost their trematodes, highlighting the fact that trematode lifespan can be short, while SA cockles maintained their trematode load. When cockles were the second intermediate host, there was no effect of site of origin on cockle condition index and survival. The effect on growth rate was mostly due to initial cockle length. Within each treatment, the only significant effect of trematode infection on growth was found for H. interrupta at SA. The 23% growth deficit observed could be due to the disruption of cockle shell synthesis in the mantle margin. During the transplant experiment, cockles were also infected at an exceptionally high rate by Bucephalus minimus, a trematode which invades most of the tissues and uses the cockle as a first intermediate host. Surprisingly, there was an effect on the growth rate and condition index of cockles at only one of the sites under study. This field experiment succeeded in quantifying the moderately negative effect of trematode parasites on the growth and condition of their host and suggested the existence of interactions with as yet unknown factors.
(Marine Ecology Progress Series. vol. 471, n° 0171-8630, pp. 111-121, 12/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UM5, UCC
Mise au point d’un indice diatomique pour les cours d’eau de la Réunion (IDR) : Construction de la démarche biomathématique, résultats et perspectives
L'étude ayant conduit à la genèse de l'IDR (Indice Diatomique Réunion) s'est appuyée sur l’acquisition de 269 relevés taxinomiques des espèces rencontrées sur place et de données associées de chimie des eaux, obtenues sur un réseau de 56 sites à l'occasion de 5 campagnes de prélèvements de terrain. L'analyse de ces données a permis une caractérisation plus ou moins consolidée des préférences écologiques de 343 espèces, le repérage de communautés diatomiques-types caractéristiques de conditions environnementales particulières et, au final, la mise au point de ce nouvel indice, qui mobilise les profils de qualité écologique de 175 espèces suffisamment occurrentes.
(pp. 22, 12/04/2026)
UR REBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Synergie de l’imagerie satellitaire optique et radar pour la cartographie des habitats du Bassin d'Arcachon
L’imagerie satellitaire optique dispose d’un bon potentiel de cartographie des espaces naturels littoraux de par l’emprise spatiale, la haute résolution et le recul temporel qu’offrent les 25 ans d’archives image SPOT. Cet article explore le potentiel des images SAR (Synthetic Aperture Radar) Haute Résolution (HR) pour la cartographie des habitats intertidaux en complément de l’imagerie optique traditionnelle. Dans un premier temps, l’article évalue le potentiel de discrimination des habitats du Bassin d’Arcachon à partir d’une série temporelle constituée de 15 images TerraSAR-X et de 2 images ALOS-PALSAR acquises entre 2007 et 2011. L’étude a permis de caractériser les signatures radar de la couverture sédimentaire intertidale, des herbiers de zostères, des bancs d’huitres et de la végétation du schorre. Les bancs d’huîtres, les structures ostréicoles et le schorre ont des signatures radar très particulières (forte brillance) ce qui permet de les distinguer de la slikke, qu’elle soit végétalisée ou non, et de lever la confusion issue de l’analyse d’une image optique seule. Dans un second temps, l’article développe les résultats issus de la classification des données optiques et radar concaténées sur le secteur de La Hume. Les résultats les plus satisfaisants sont obtenus avec une classification supervisée de Mahalanobis basée sur les 4 bandes SPOT d’une image estivale, la bande XS2 d’une image SPOT d’hiver et une bande radar HH TerraSAR-X. Cette approche cartographique combinant données optiques-radar multi-temporelles permet de lever les principales difficultés ayant motivé cette étude. Des développements sont toutefois encore nécessaires pour parvenir à mieux cartographier les grands ensembles végétaux du schorre et à détecter les biofilms à microphytobenthos ainsi que les dépôts de macro-algues.
(pp. 10, 12/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR TETIS, Cirad, IRSTEA
Consistency in diatom response to metal-contaminated environments
Diatoms play a key role in the functioning of streams, and their sensitivty to many environmental factors has led to the development of numerous diatom-based indices used in water quality assessment. Although diatom-based monitoring of metal contamination is not currently included in water qual ty monitoring programs, the effects of metals on diatom commun ties have been studied in many polluted watersheds as well as in laboratory experiments, underlying their high potential for metal contamination assessment. Here, we review the response of diatoms to metal pollution from individual level (e.g. size, growth form, and morphological abnormalities) to community structure (replacement of sensitive species by tolerant ones). These potential effects are then tested using a large multi-country database combining diatom and metal information. Metal contamination proved to be a strong driver of the community structure, and enabled for the identification of tolerant species like Cocconeis placentula var. euglypta, Eolimna minima , Fragilaria gracilis, Nitzschia sociabilis, Pinnularia parvulissima, and Surirella angusta. Among the traits tested, diatom cell size and the occurrence of diatom deformities were found to be good indicators of high metal contamination. This work provides a basis for further use of diatoms as indicators of metal pollution.
(pp. 117-146, 12/04/2026)
UR REBX, IRSTEA, IRSTEA, IRSTEA, IRSTEA, ICRA, UdG, UdG, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Removal of xenobiotics by adsorption on two mineral adsorbent materials as an alternative to activated carbon: a comparative batch approach
Xenobiotics, such as some pharmaceuticals and pesticides, are poorly treated in wastewater treatment plants (WWTPs). Thus, their occurrence into the aquatic environment is more and more highlighted. Adsorption process on materials, such as in tertiary stage of treatment, could be a solution to decrease the concentrations of xenobiotics in effluents that are discharged into the aquatic environment. We carried out an original experiment involving treated domestic wastewater spiked with a cocktail of 10 xenobiotics known as being poorly eliminated in WWTPs (8 pharmaceuticals and 2 pesticides). Two mineral adsorbent materials (expanded clay and zeolite), representing a possible alternative to activated carbon, were evaluated for the adsorption of the cocktail of xenobiotics. We studied the influence of the concentration level of xenobiotics on adsorption results. We focused on the concentrations near from usual effluent ranges to be representative with conditions faced in tertiary treatment stage. If activated carbon was the most efficient adsorbent material, both alternative adsorbent materials showed good adsorption efficiencies for the 10 xenobiotics (in the range of 50-100% depending on the couple adsorbent material / xenobiotic). Kd partition coefficients were quantified for different xenobiotics concentration ranges. At low concentration (0.1 – 10 µg/L), expanded clay showed higher Kd values than at high concentration (100 – 1000 µg/L) for a majority of xenobiotics (7 among 10). Kd values for zeolite seemed to be independent of xenobiotic concentration levels. Our results point out that mineral microporous adsorbent are credible alternatives to activated carbon for adsorption of xenobiotics usually known to be poorly eliminated in WWTPs. The results suggest a possible use into a tertiary stage of treatment in wastewater treatment plants.
(pp. 6, 12/04/2026)
UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UM
Sedimentary processes in the Cap-Ferret canyon (Bay of Biscay, NE Atlantic): from seasonal to century time scales
(12/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UCAD, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, JAMSTEC
Reduction of refractory micropollutants in treated wastewater by advanced tertiary treatments
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. 4, 12/04/2026)
IRSTEA, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR MALY, IRSTEA
Assessing the effect of macrobenthos diversity on the mineralisation of sediment organic matter
(12/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LGE, UPD7, IPG Paris, LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS, LOBB, OOB, UPMC, CNRS, UPMC, INSU - CNRS, CNRS, OOB, SU, CNRS, CNRS
Les collections scientifiques de l'université Bordeaux 1. Sciences et Technologies
De nombreuses universités scientifiques possèdent des collections. L'université Bordeaux 1 possède neuf grandes collections concernant les domaines de la préhistoire, de l'anthropologie, de la géologie terrestre et marine, de la paléontologie et micropaléontologie, de la biologie, de l'astronomie et d'un fonds ancien et moderne d'ouvrages scientifiques. Certaines collections sont riches de milliers de spécimens : fossiles d'invertébrés, ossements de vertébrés, silex taillés, ossements humains préhistoriques ou historiques, animaux naturalisés, carottes de sédiments, instruments d'astronomie et livres anciens. Ces collections ont été constituées par des privés ou des chercheurs et ont ensuite été léguées à l'université. Il est important d'identifier les collectionneurs et surtout les motivations qui ont guidé leurs choix : recherche, enseignement, passion. Entre histoires personnelles et histoires locales, ce regard sur les collections est aussi une porte ouverte sur l'histoire des Sciences.
(In Situ : Revue des patrimoines. vol. -, pp. on line, 12/04/2026)
L3AB, UB, INSU - CNRS, CNRS, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, LAB, UB, INSU - CNRS, CNRS, UB, PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS