Transcriptome profile analysis reveals specific signatures of pollutants in Atlantic eels
Identifying specific effects of contaminants in a multi-stress field context remain a challenge in ecotoxicology. In this context, "omics" technologies, by allowing the simultaneous measurement of numerous biological endpoints, could help unravel the in situ toxicity of contaminants. In this study, wild Atlantic eels were sampled in 8 sites presenting a broad contamination gradient in France and Canada. The global hepatic transcriptome of animals was determined by RNA-Seq. In parallel, the contamination level of fish to 8 metals and 25 organic pollutants was determined. Factor analysis for multiple testing was used to identify genes that are most likely to be related to a single factor. Among the variables analyzed, arsenic (As), cadmium (Cd), lindane (γ-HCH) and the hepato-somatic index (HSI) were found to be the main factors affecting eel's transcriptome. Genes associated with As exposure were involved in the mechanisms that have been described during As vasculotoxicity in mammals. Genes correlated with Cd were involved in cell cycle and energy metabolism. For γ-HCH, genes were involved in lipolysis and cell growth. Genes associated with HSI were involved in protein, lipid and iron metabolisms. Our study proposes specific gene signatures of pollutants and their impacts in fish exposed to multi-stress conditions.
(Ecotoxicology. vol. 24, n° 0963-9292, pp. 71-84, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CQFD, IMB, UB, Bordeaux INP, CNRS, Inria, IBIS, ULaval, ULaval, INRS - ETE, INRS, LMBA, UBS, UBO EPE, CNRS, UR EABX, IRSTEA
Development of solid-phase microextraction to study dissolved organic matter-Polycyclic aromatic hydrocarbon interactions in aquatic environment
Solid-phase microextraction coupled with gas chromatography and mass spectrometry (SPME-GC-MS) was developed for the study of interactions between polycyclic aromatic hydrocarbons (PAHs) and dissolved organic matter (DOM). After the determination of the best conditions of extraction, the tool was applied to spiked water to calculate the dissolved organic carbon water distribution coefficient (KDOC) in presence of different mixtures of PAHs and Aldrich humic acid. The use of deuterated naphthalene as internal standard for freely dissolved PAH quantification was shown to provide more accuracy than regular external calibration. For the first time, KDOC values of 18 PAHs were calculated using data from SPME-GC-MS and fluorescence quenching; they were in agreement with the results of previous studies. Competition between PAHs, deuterated PAHs and DOM was demonstrated, pointing out the non-linearity of PAH-DOM interactions and the stronger interactions of light molecular weight PAHs (higher KDOC values) in absence of high molecular weight PAHs. \textcopyright 2013 Elsevier B.V.
(Analytica Chimica Acta. vol. 807, n° 0003-2670, pp. 51--60, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Persistent Organic Pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic coast) -Part 1: Bioaccumulation
The aim of this study was to determine 1) the relevance of using the Pacific oyster Crassostrea gigas as a sentinel organism, at a juvenile stage, for polycyclic aromatic hydrocarbon (PAH) and persistent organic pollutant (polychlorobiphenyls, PCBs, polybromodimethylethers, PBDEs, and organochlorine pesticides, OCPs) contamination, 2) the potential levels of chemical organic contamination in the Marennes-Oleron Bay, and their potential sources 3) the potential influence of physiological or environmental factors on contaminant body burdens in oysters. To this end, juvenile oysters purchased from a oyster hatchery were transplanted to a reference site, in Bouin, and to different transplantation sites in the Marennes-Oléron Bay, the first oyster production area in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Transplantations were done during summer and winter. Whole oyster soft tissues from each site were analyzed for PAHs, PCBs, PBDEs and OCPs. Results obtained with a transplantation period of 3 months suggest that the C. gigas, at the juvenile stage, is a relevant sentinel organism for short-term contamination for these contaminants. In addition, no significant effects of physiological factors on contaminant body burdens were observed. A principal component analysis performed with chemical body burdens allowed them to be separated into three groups: 1) the reference site, 2) Les Palles (LP) and Boyard (BOY) in winter and 3) all the other sites. The group of LP and BOY was clearly defined by the levels of PAHs and OCPs, suggesting higher levels of contamination of these chemical compounds on these sites, potentially due to local contamination sources. In addition, no relevant effects of physiological or environmental factors on contaminant body burdens were observed. Results suggest also a predominance of contaminants related to agricultural activities along the Marennes-Oléron Bay, and therefore, further studies on the presence of pesticides in this region should be considered.
(Science of the Total Environment. vol. 514, n° 0048-9697, pp. 500-510, 26/06/2026)
PUJ, LIENSs, INSU - CNRS, ULR, CNRS, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Bacciger bacciger (Trematoda: Fellodistomidae) infection effects on wedge clam Donax trunculus condition
Wedge clams Donax trunculus inhabit high-energy environments along sandy coasts of the northeastern Atlantic Ocean and the Mediterranean Sea. Two sites were sampled monthly, one in Morocco (Mehdia), where the density was normal, and one in France (Biscarosse), where the density was very low. We tested the hypothesis that the difference in density between the sites was related to infection by the trematode parasite Bacciger bacciger. Identity of both the parasite and the host were verified using anatomical and molecular criteria. Parasite prevalence (i.e. the percentage of parasitized clams) was almost 3 times higher at Biscarosse. At this site, overall prevalence reached 32% in July and was correlated with the migration of several individuals (with a prevalence of 88%) to the sediment surface. After this peak, prevalence decreased rapidly, suggesting death of parasitized clams. The deleterious effect of B. bacciger on wedge clams was also supported by our calculations indicating that the weight of the parasite made up to 56% of the total weight of the parasitized clams. However, condition indices of trematode-free clams were also lower in Biscarosse than in Mehdia or other sites, suggesting that other factors such as pollutants or microparasites (Microcytos sp.) may alter wedge clam population fitness in Biscarosse.
(Diseases of Aquatic Organisms. vol. 111, n° 0177-5103, pp. 259-267, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UM5
Atmospheric reactions of 9,10-anthraquinone
The probably carcinogenic compound 9,10-anthraquinone is mainly existing in the atmosphere in the particulate phase and is often detected and measured among other oxygenated PAHs in atmospheric samples. Its fate, once released or formed in the atmosphere, still remains unknown. In this work, heterogeneous chemical oxidation processes of 9,10-anthraquinone were investigated with ozone (O 3), nitrogen dioxide (NO 2) and hydroxyl radical (OH). The study of 9,10-anthraquinone adsorbed on silica particles showed no reactivity with O 3 and NO 2. On the other hand, the reaction with OH radicals was observed and led to the formation of 1-hydroxy-9,10-anthraquinone, another oxidation product recognized as possibly carcinogenic to humans. This study showed that reactions with ozone and nitrogen dioxide are unlikely to contribute to atmospheric degradation of 9,10-anthraquinone, whereas reactions with OH radicals could be involved in 9,10-anthraquinone degradation processes, even if such reaction is probably very slow under ambient conditions.
(Chemosphere. vol. 107, n° 0045-6535, pp. 1-6, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INERIS
Benthic foraminifera from the deep-water Niger delta (Gulf of Guinea): Assessing present-day and past activity of hydrate pockmarks
We present ecological and isotopic (δ18O and δ13C) data on benthic foraminifera sampled from 4 deep-sea stations in a pockmark field from the deep-water Niger delta (Gulf of Guinea, Equatorial Atlantic Ocean). In addition, a series of sedimentological and (bio)geochemical data are shown to back up foraminiferal observations. All stations are located within 1.2km of each other, so prevailing oceanographic conditions can be assumed to be similar at each site. Two of the sites (GMMC-01 and GMMC-02) are located in a pockmark (named "pockmark A") where current methane seepages were recorded by ROV observations. A third station (GMMC-03) is located in the topographic depression interpreted as a collapsed pockmark (named "pockmark B"). The fourth site (GMMC-04) is a reference station, without evidence of past or present seepages. Our observations show that degraded organic matter with low bio-availability is present at all stations with a preferential burial of organic compounds in topographic depressions (GMMC-03 station). Authigenic aragonite is abundant in surface sediments at stations GMMC-01 and -02. Its precipitation is likely related to high rates of methane oxidation during past seep events in episodically active pockmark A. In contrast, the absence of anaerobic methanotrophic Archaea (ANME) during the sampling period (November 2011) suggests that only moderate sulphide and methane oxidation take place close to the sediment-water interface. Compared to the reference site GMMC-04, living foraminifera at the collapsed and episodically active pockmarks show minor changes in terms of diversity, standing stocks and faunal composition. However, the δ13C signal of living and dead (but well-preserved) foraminiferal species (Ceratobulimina contraria, Melonis barleeanus, Uvigerina peregrina) is depleted in the episodically active pockmark A compared to the other stations. Overgrowth of authigenic carbonate on altered foraminifera generates an important shift to lower δ13C values. Dead faunas carry a complex time-averaged message, integrating taphonomic gains and losses related to the temporal variability of gas emission. They reveal major faunal differences that may be useful to detect gas hydrate seepages in different pockmark stages. © 2014 Elsevier Ltd.
(Deep Sea Research Part I: Oceanographic Research Papers. vol. 94, n° 0967-0637, pp. 87-106, 26/06/2026)
BIAF, UA, IPREM, UPPA, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EGID, LASIRE, INC-CNRS, CNRS, LEP, EEP, IFREMER, IFREMER, AWI
Echantillonneurs passifs : évaluation de l’exposition des biofilms aux mélanges de pesticides, et du risque écotoxique dans les cours d’eau
La contamination généralisée des cours d’eau par les pesticides, généralement en mélanges et à concentrations relativement faibles, requiert la prise en compte dans le diagnostic de la complexité de l’exposition. Le développement récent de l’échantillonnage passif des contaminants a permis d’une part de mieux considérer la diversité des contaminants présents dans l’environnement, et d’abaisser leurs limites de détection, fournissant ainsi un panorama plus exhaustif de la contamination réelle. Le biofilm est une communauté complexe, composée de microalgues, de bactéries, de champignons, de protozoaires, etc. enchâssés dans une matrice polysaccharidique. Son utilisation en écotoxicologie revêt un haut degré de pertinence environnementale, comparé aux espèces modèles utilisées traditionnellement. Elle permet de mieux comprendre et prédire les impacts réels de contaminants pour l’écosystème, bien mieux que l’extrapolation de résultats déconnectés de la complexité des conditions de milieu (diversité des organismes, et de leurs relations). Le modèle biofilm a ainsi été utilisé avec succès dans de nombreuses études écotoxicologiques au laboratoire, utilisant des contaminants seuls ou en combinaisons simples (binaires, ternaires) de substances. Cependant, la qualification du risque écotoxique associé aux mélanges de contaminants est difficilement envisageable par ce biais, la multiplicité des mixtures possibles (en termes de composition et de concentrations) empêchant de tester toutes les combinaisons susceptibles d’être rencontrées in situ. Nous proposons ici de présenter les avancées récentes permises par le couplage entre échantillonnage passif et écotoxicologie, pour la mesure du potentiel toxique dans les milieux aquatique, et pour la mise en ½uvre d’expérimentations plus réalistes environnementalement.
(pp. 2, 26/06/2026)
UR EABX, IRSTEA, UR MALY, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Méthodes phytobenthiques cours d’eau (Réunion et Antilles) : Cadre général et méthodologique
Pour favoriser la mise en application de la DCE dans les DOM, des programmes locaux de développement de bio-indicateurs ont été entrepris à partir de 2008 sous la maîtrise d’ouvrage principale des gestionnaires locaux des hydrosystèmes (Offices de l’Eau et DEALs), avec des participations financières complémentaires émanant, selon le cas, du niveau national (Ministère de l’Outre-Mer, ONEMA), de l’Union Européenne (FEDER) et d’une part de financement propre souvent apportée par les équipes participant à la réalisation concrète des programmes. Dans ce cadre, le consortium Asconit-Irstea a pris en charge, entre 2008 et 2013, la réalisation de programmes de mise au point de nouveaux indices diatomiques des cours d’eau à la Réunion et aux Antilles et autofinancé, selon le cas, de 25 à 30 %.du coût total de chacun des projets. Les démarches Réunion et Antilles ont suivi des cheminements méthodologiques relativement parallèles et comparables sur le plan de la démarche biomathématique mise en oeuvre. A partir des données taxonomiques et abiotiques obtenues dans le cadre de 7 à 8 campagnes d’échantillonnage de terrain, des référentiels conséquents, atteignant au final 345 doublets de données exploitables à la Réunion et 607 aux Antilles, ont pu être constitués et faire l’objet de diverses analyses biomathématiques de données. Celles-ci se sont organisées en 5 étapes spécifiques d’investigation : 1) une biotypologie visant, à partir de la composition des assemblages, à repérer leur structuration sous les forçages naturels et sous l’emprise des pressions anthropiques ; 2) Une phase d’analyse exploratoire des données abiotiques (ACP complète ) visant à repérer l’organisation des données et les gradients principaux rencontrés au niveau physico-chimie et chimie de l’eau ; 3) Une analyse canonique des correspondances (ACC complète) visant à repérer la co-structuration des données générales d’environnement et des assemblages floristiques ; 4) une analyse canonique des correspondance restreinte, selon le cas, à 9 ou 10 variables physico-chimiques fortement influencées par les activités anthropiques (ACC restreinte), qui a permis de formaliser un gradient composite multimétrique d’anthropisation (GCMA) assis à la fois sur les données abiotiques et sur la matrice de réponse des assemblages diatomiques ; 5) le calcul du profil de qualité des espèces intervenant dans le calcul des futurs indices diatomiques, après seuillage sur un double critère d’occurrence et d’abondance relative minimale dans au moins un relevé, suivi de la formulation de l’indice. Il a ainsi été mis au point 2 versions successives d’IDR (Réunion) et d’IDA (Antilles) permettant au final de tirer parti de l’ensemble des données devenues mobilisables sur ces DOM à la fin 2013 et de remédier aux défauts de jeunesse diagnostiqués sur leur première version. Ces indices fonctionnent sur un principe général de repérage de taxons d’alerte, qui contribuent à la dégradation de la note d’indice avec un poids différent selon la catégorie à laquelle ils appartiennent. Un système d’évaluation propre à chaque DOM a ensuite été élaboré, conduisant à la proposition d’une grille spécifique d’évaluation, exprimée en EQRs, par grand ensemble naturel de chacun de ces DOM (2 grands ensembles naturels à la Réunion, 2 pour les Antilles regroupées). Ces grilles sont utilisables au relevé et devront faire l’objet d’une adaptation spécifique pour une agrégation temporelle au site. Elles ont été intégrées à un projet de nouvel Arrêté d’Evaluation dont la parution est prévue début 2015.
(pp. 19, 26/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Effets de la qualité des sédiments de frayère sur le développement embryo-larvaire de l'esturgeon européen (Acipenser sturio)
Les embryons et larves d'esturgeon européen ont été exposés aux substrats de 2 frayères situées sur la Dordogne et la Garonne. Les individus exposés au substrat de La Réole (Garonne) présentent une augmentation du taux de malformation, une altération des capacités physiologique et natatoire.
(pp. 15, 26/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Multiscale patterns in the diversity and organization of benthic intertidal fauna among French Atlantic estuaries
Based on a parallel sampling conducted during autumn 2008, a comparative study of the intertidal benthic macrofauna among 10 estuarine systems located along the Channel and Atlantic coasts of France was performed in order to assess the level of fauna similarity among these sites and to identify possible environmental factors involved in the observed pattern at both large (among sites) and smaller (benthic assemblages) scales. More precisely this study focused on unraveling the observed pattern of intertidal benthic fauna composition and diversity observed at among-site scale by exploring both biotic and abiotic factors acting at the among- and within-site scales. Results showed a limited level of similarity at the among-site level in terms of intertidal benthic fauna composition and diversity. The observed pattern did not fit with existing transitional water classification methods based on fish or benthic assemblages developed in the frame of the EuropeanWater Framework Directive (WFD). More particularly, the coastal plain estuaries displayed higher among-site similarity compared to ria systems. These coastal plain estuaries were characterized by higher influence of river discharge, lower communication with the ocean and high suspended particulate matter levels. On the other hand, the ria-type systems were more dissimilar and different from the coastal plain estuaries. The level of similarity among estuaries was mainly linked to the relative extent of the intertidal "Scrobicularia plana-Cerastoderma edule" and "Tellina tenuis" or "Venus" communities as a possible consequence of salinity regime, suspended matter concentrations and fine particles supply with consequences on the trophic functioning, structure and organization of benthic fauna. Despite biogeographical patterns, the results also suggest that, in the context of the WFD, these estuaries should only be compared on the basis of the most common intertidal habitat occurring throughout all estuarine systems and that the EUNIS biotope classification might be used for this purpose. In addition, an original inverse relation between γ-diversity and area was shown; however, its relevance might be questioned.
(Journal of Sea Research (JSR). vol. 90, n° 1385-1101, pp. 95-110, 26/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], LOBB, OOB, UPMC, CNRS, UPMC, INSU - CNRS, CNRS, MMS, UM, UN UFR ST, UN, UFR SPB, UN, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, LERLR / LEROC, COAST, IFREMER, LERBN, COAST, IFREMER, UBO EPE, GEMEL-Normandie, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, STARESO, LIENSs, INSU - CNRS, ULR, CNRS