Cadmium uptake by the European eel: Trophic transfer in field and experimental investigations
Due to its status of threatened species and being heavily contaminated by metals, the European eel (Anguilla anguilla) was selected to investigate cadmium contamination levels of fish settled along a historically cadmium-contaminated hydrosystem, the GaronneGironde continuum (France), according to its various location sites and fish length. Results have shown an important site effect on cadmium concentrations in liver but not in gills, highlighting the possible predominance of the trophic exposure route. Subsequently, uncontaminated eels were experimentally exposed to cadmium by water uptake and/or trophic route(s). Eels were fed with different preys: white shrimps collected in an unpolluted area in the Gironde estuary, and cadmium-enriched shrimps. Data obtained tend to show that the use of cadmium-enriched food during experimental investigations triggers an underestimation of the metal trophic transfer rate. These two complementary approaches provide some elements to suggest that the trophic route plays an important role in cadmium contamination of wild eels.
(Ecotoxicology and Environmental Safety. vol. 70, n° 0147-6513, pp. 10-19, 26/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EPBX, CEMAGREF
The Fetch Campaign, study of the turbulent fluxes, surface waves and remotely sensed parameters in fetch limited situations
description of the Fetch Campaign conducted in the Golfe du Lion in Mediterranéean sea
(26/08/2026)
CETP, UVSQ, INSU - CNRS, CNRS, SA, UVSQ, UPMC, INSU - CNRS, CNRS, IRPHE, AMU, ECM, CNRS, LEPI, UTLN, APL/RSMAS, RSMAS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LAERO, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNRS, FIMR, DIROP/MAR, DIROP, IFREMER
Nitrous oxide emissions from tropical hydroelectric reservoirs
We report original data on nitrous oxide (N2O) fluxes from two tropical reservoirs, their rivers below the dam, and from natural aquatic ecosystems and rainforest soils in French Guiana and Panama. We also review published N2O fluxes from other tropical reservoirs and natural environments. We show that: (1) N2O emissions from tropical reservoirs occur mainly at the reservoir surface, fluxes downstream of dams being minor; (2) Because pre-flooding natural N2O fluxes are significant, the net N2O emissions from reservoirs are less than ∼50-70% of gross N2O emissions; (3) the contribution of N2O to the global warming potential of emissions from reservoirs could be significant for gross emissions, but less than 10% for net emissions, disregarding N2O degassing emissions.
(Geophysical Research Letters. vol. 35, n° 0094-8276, pp. L06404, 26/08/2026)
LAERO, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LACy, INSU - CNRS, UR, CNRS
Organic matter dynamics and budgets in the turbidity maximum zone of the Seine Estuary (France)
Organic matter was studied in the turbidity maximum zone (TMZ) of the Seine Estuary during 8 tidal cycles from April to October in 2001, 2002 and 2003, covering a salinity range from 0 to 27. The hydrological conditions were quite varied (extremely wet in 2001, unusually dry in 2003). A particularly striking feature is the high organic matter content in the suspended solids (SS) of the Seine estuary (4-5%). By determining micro-organism activity and organic carbon partitioning, either linked to particles or in dissolved forms, and estimating the TMZ water volumes, together with SS, we extrapolated these activities and stocks to the whole TMZ. Carbon metabolism in the TMZ and fluxes upstream of the TMZ were compared on the dates of field surveys, and the routes and fate of carbon in the TMZ were quantified in order to learn about the trophic status of this estuarine zone in terms of autotrophy vs. heterotrophy. The upstream total organic carbon (TOC) fluxes (48% of particulate organic carbon (POC), 52% of dissolved organic carbon (DOC) on average) varied fourfold between the surveys, reaching the highest value of 280 TC d-1 during the wet summer of 2001; and the lowest value of about 70 TC d-1 in August 2003. Whereas nearly all of the DOC flux entering the TMZ reaches the coastal marine zone, mostly (at least 85%) in a refractory form, the POC accumulates in the TMZ of the estuarine channel, particle exportation being negligible. In the TMZ, biodegradation of DOC was, on average, much less (only a 2% decrease in the BDOC/DOC ratio between the TMZ upstream and downstream fluxes) than biodegradation of POC (11%). A simplified model of the TMZ (LIFT- Lumped Idealisation of the ecological Functioning in estuarine Turbidity maximum) was constructed for investigating the dynamics of organic matter on a seasonal scale. The agreement between observation and calculation allowed us to run sensitivity tests using new constraints; reductions of the upstream fluxes of phytoplankton and organic carbon showed that the high content of organic matter, originating mostly from the domestic effluents of the Paris conurbation, can explain the high organic content of the Seine estuary TMZ.
(Estuarine, Coastal and Shelf Science. vol. 77, n° 0272-7714, pp. 150-162, 26/08/2026)
LPMA, UPMC, UPD7, CNRS, UPMC, SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, GEOSCIENCES, PSL, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ULB
Contribution du cadmium au déclin des populations d'anguille européenne (Anguilla anguilla) : impact sur la réussite de la migration de reproduction
Les populations d'anguille européenne (Anguilla anguilla L.) déclinent sévèrement depuis quelques décennies, menaçant cette espèce d'extinction. Dans ce contexte, nous avons étudié l'effet potentiel du cadmium (Cd), un métal non essentiel largement répandu dans l'environnement, sur les capacités de reproduction de l'anguille européenne.
(pp. 1, 26/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MNHN, UR EPBX, CEMAGREF
How cadmium could compromise the completion of the european eel's reproductive migration
The European eel (Anguilla anguilla L.) is severely threatened with extinction. Surprisingly, even though their unusual life cyclemakesthem particularly vulnerable to pollution, the possible contribution of contamination remains especially poorly known. Here we have investigated the possible effect of cadmium (Cd), a widespread nonessential metal, on eel reproductive capacities. Both control and Cd precontaminated female silver eels were experimentally matured and forced to swim in metal-free conditions to mimic their reproductive migration. Cd pre-exposure was found to strongly stimulate the pituitary-gonad-liver axis of maturing female silver eels leading to early and enhanced vitellogenesis. This was followed by a strong phenomenon of oocyte atresia and eel mortality. These phenomena occurred before oocytes could reach full maturation and were associated with a large entry of both vitellogenin and Cd into the ovaries. Indeed, a redistribution of previously stored cadmium, even from the low Cd levels of control eels, was observed during sexual maturation. Atresia and mortality phenomena were also associated with an overexpression of the pituitary gene encoding the growth hormone, a marker of physiological stress and energy reserves exhaustion. Significantly, these devastating effects of Cd were observed in organisms that presented liver and kidney Cd concentrations still below those observed in eels from Cd contaminated hydrosystems. Our research shows how common levels of cadmium contamination could disrupt endocrine pathways implicated in gonad maturation and subsequently impair reproductive capacity of eel future genitors.
(Environmental Science and Technology. vol. 42, n° 0013-936X, pp. 4607-4612, 26/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS, BOME, MNHN, UPMC, CNRS, UR EPBX, CEMAGREF
Silver behaviour along the salinity gradient of the Gironde estuary: reactivity and bioaccumulation in eel (anguilla anguilla)
The objective of the present work is to document for the first time Ag concentration levels and behaviour in the salinity gradient of the highly turbid, macrotidal Gironde Estuary. Furthermore, a potential impact of estuarine Ag dissolution on bioaccumulation in European eels is discussed.
(pp. 2, 26/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EPBX, CEMAGREF
Brown muscle disease (BMD), an emergent pathology affecting Manila clam Ruditapes philippinarum in Arcachon Bay (SW France)
We describe an emerging pathology, brown muscle disease (BMD), which specifically affects the Manila clam Ruditapes philippinarum in Arcachon Bay (France). BMD induces a transformation of the posterior adductor muscle, which becomes infused by conchiolin and calcified, reducing the ability of clams to bury. The disease affects both types of muscular tissue, with striated muscle becoming affected to a higher degree than smooth muscle. Two indices were created to quantify the symptoms: the Muscle Print Index, used for empty and live shells, and the Final Disease Index, utilized for live clams only. Histological sections were made and observed under light microscopy to examine the muscular damage and to investigate a causal agent. Sections revealed an important inflammatory response with a large invasion of hemocytes into tissues and a heavy necrosis of muscular fibers. Additionally, molecular biology analyses were carried out to search for bacteria and protozoan agents using generic primers. In both histological and molecular assays, bacteria and protozoans were discounted. We monitored 4 sites scattered around the bay over 2 yr. The mean prevalence was <12% without seasonal variation in 3 sites against 30% and a winter peak in 1 site. The latter site was accurately surveyed and revealed that clams at the sediment surface (abnormal position) were affected 3 times more frequently than buried clams (normal position)
(Diseases of Aquatic Organisms. vol. 80, n° 0177-5103, pp. 219-228, 26/08/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LRHA, HGS, IFREMER
Seasonal export of plankton foraminifera in the Bay of Biscay
(26/08/2026)
LPGN, UN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Particle fluxes and recent sediment accumulation on the Aquitanian margin of Bay of Biscay
(26/08/2026)
LPGN, UN, CNRS, LOV, OOVM, UPMC, INSU - CNRS, CNRS, UPMC, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA