Le cuivre dans les sols viticoles : les apports du projet PHYTOCOTE
(15/06/2022)
UMR ISPA, Bordeaux Sciences Agro, INRAE, UR ETTIS, INRAE, Département EcoSocio, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Bioaccumulation of per- and polyfluoroalkyl substance in fish from an urban river: Occurrence, patterns and investigation of potential ecological drivers
Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in aquatic environments and a recent shift toward emerging PFAS is calling for new data on their occurrence and fate. In particular, understanding the determinants of their bioaccumulation is fundamental for risk assessment purposes. However, very few studies have addressed the combined influence of potential ecological drivers of PFAS bioaccumulation in fish such as age, sex or trophic ecology. Thus, this work aimed to fill these knowledge gaps by performing a field study in the Seine River basin (France). Composite sediment and fish (European chub, Squalius Cephalus) samples were collected from four sites along a longitudinal transect to investigate the occurrence of 36 PFAS. Sediment molecular patterns were dominated by fluorotelomer sulfonamidoalkyl betaines (i.e. 6:2 and 8:2 FTAB, 46% of ∑PFAS on average), highlighting the non-negligible contribution of PFAS of emerging concern. C9–C14 perfluoroalkyl carboxylic acids, perfluorooctane sulfonic acid (PFOS), perfluorooctane sulfonamide (FOSA) and 10:2 fluorotelomer sulfonate (10:2 FTSA) were detected in all fish samples. Conversely, 8:2 FTAB was detected in a few fish from the furthest downstream station only, suggesting the low bioaccessibility or the biotransformation of FTABs. ∑PFAS in fish was in the range 0.22–3.8 ng g−1 wet weight (ww) and 11–140 ng g−1 ww for muscle and liver, respectively. Fish collected upstream of Paris were significantly less contaminated than those collected downstream, pointing to urban and industrial inputs. The influence of trophic ecology and biometry on the interindividual variability of PFAS burden in fish was examined through analyses of covariance (ANCOVAs), with sampling site considered as a categorical variable. While the latter was highly significant, diet was also influential; carbon sources and trophic level (i.e. estimated using C and N stable isotope ratios, respectively) equally explained the variability of PFAS levels in fish.
(Environmental Pollution. vol. 303, n° 0269-7491, pp. 119165, 15/06/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SIAAP
Trophic transfer of copper decreases the condition index in Crassostrea gigas spat in concomitance with a change in the microalgal fatty acid profile and enhanced oyster energy demand
Due to new usages and sources, copper (Cu) concentrations are increasing in the Arcachon Basin, an important shellfish production area in France. In the present paper, the trophic transfer of Cu was studied between a microalga, Tetraselmis suecica, and Crassostrea gigas (Pacific oyster) spat. An experimental approach was developed to assess Cu exposure, transfer and toxicity on both phytoplankton and spat. Exposure of microalgal cultures to Cu for 7–8 days (3.1 ± 0.1, 15.7 ± 0.2 and 50.4 ± 1.0 μg Cu·L−1 for the control, Cu15 and Cu50 conditions, respectively) led to concentrations in microalgae (28.3 ± 0.9 and 110.7 ± 11.9 mg Cu·kg dry weight−1 for Cu15 and Cu50, respectively) close to those measured in the field. Despite Cu accumulation, the physiology of the microalgae remained poorly affected. Exposed cultures could only be discriminated from controls by a higher relative content in intracellular reactive oxygen species, and a lower relative content in lipids together with a reduced metabolic activity. By contrast, the fatty acid profile of microalgae was modified, with a particularly relevant lower content of the essential polyunsaturated fatty acid 22:6n-3 (docosahexaenoic acid [DHA]). Following 21 days of spat feeding with Cu15 and Cu50 microalgal cultures, trophic transfer of Cu was observed with a high initial Cu concentration in spat tissues. No effect was observed on oxidative stress endpoints. Cu exposure was responsible for a decrease in the spat condition index, an outcome that could be related to an insufficient DHA supply and extra energy demand as suggested by the overexpression of genes involved in energy metabolism, ATP synthesis and glycogen catabolism. © 2022
(Science of the Total Environment. vol. 824, n° 0048-9697, 10/06/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Comment les surfeurs sauvent des vies sur les plages françaises
(02/06/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Can artificial magnetic fields alter the functional role of the blue mussel, Mytilus edulis?
(Marine Biology. vol. 169, n° 0025-3162, pp. 75, 01/06/2022)
LEMAR, IRD, IFREMER, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA
Chlordecone-contaminated epilithic biofilms show increased adsorption capacities
The rivers of Guadeloupe and Martinique (French West Indies) show high levels of chlordecone (CLD) contamination. This persistent molecule has a dramatic impact on both aquatic ecosystems and human health. In these rivers, epilithic biofilms are the main endogenous primary producers and represent a central food source for fish and crustaceans. Recently, their viscoelastic properties have been shown to be effective in bio-assessing pollution in tropical environments. As these properties are closely related to the biochemical composition of the biofilms, biochemical (fatty acids, pigments, extracellular polymeric substances (EPS) monosaccharides) and molecular markers (T-RFLP fingerprints of bacteria, archaea and eukaryotes) were investigated. Strong links between CLD pollution and both biofilm biochemistry and microbial community composition were found. In particular, high levels of CLD were linked with modified exo-polysaccharides corresponding to carbohydrates with enhanced adsorption and adhesion properties. The observed change probably resulted from a preferential interaction between CLD and sugars and/or a differential microbial secretion of EPS in response to the pollutant. These changes were expected to impact viscoelastic properties of epilithic biofilms highlighting the effect of CLD pollution on biofilm EPS matrix. They also suggested that microorganisms implement a CLD scavenging strategy, providing new insights on the role of EPS in the adaptation of microorganisms to CLD-polluted environments.
(Science of the Total Environment. vol. 825, n° 0048-9697, pp. 153942, 01/06/2022)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, DGD.REVE, MNHN, MNHN, ISYEB, MNHN, EPHE, PSL, SU, CNRS, UA, UA, UMR ISEM, Cirad, IRD, EPHE, PSL, CNRS, UM, Cirad-PERSYST, Cirad, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS, UPPA, IPREM, UPPA, INC-CNRS, CNRS, EPOC
Environmental changes in SW France during the Middle to Upper Paleolithic transition from the pollen analysis of an eastern North Atlantic deep-sea core
Evaluating synchronies between climate and cultural changes is a prerequisite for addressing the possible effect of environmental changes on human populations. Searching for synchronies during the Middle-Upper Paleolithic transition (ca. 48–36 ka) is hampered by the limits of radiocarbon dating techniques and the large chronological uncertainties affecting the archaeological and paleoclimatic records, as well by their low temporal resolution. Here, we present a high-resolution, pollen-based vegetation record from the Bay of Biscay, sea surface temperature changes, additional 14 C ages, and a new IRSL date on the fine-sediment fraction of Heinrich Stadial (HS) 6. The IRSL measurements give an age of ca. 54.0 ± 3.4 ka. The paleoclimatic results reveal a succession of rapid climatic changes during the Middle-Upper Paleolithic transition in SW France (i.e. D-O 12–8 and two distinct climatic phases during HS 4). Comparison of the new paleoclimatic record with chronologically well-constrained regional archaeological changes shows that no synchronies exist between cultural transitions and environmental changes. The disappearance of Neanderthals and the arrival of Homo sapiens in SW France encompassed a long-term forest opening, suggesting that Homo sapiens may have progressively replaced Neanderthals from D-O 10 to HS 4 through competition for the same ecological niches.
(Quaternary Research, n° 0033-5894, pp. 1-18, 30/05/2022)
UB, UBM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPHE, PSL, LMJL, CNRS, Nantes univ - UFR ST, Nantes Univ
Persistent influence of precession on northern ice sheet variability since the early Pleistocene
Prior to ~1 million years ago (Ma), variations in global ice volume were dominated by changes in obliquity; however, the role of precession remains unresolved. Using a record of North Atlantic ice rafting spanning the past 1.7 million years, we find that the onset of ice rafting within a given glacial cycle (reflecting ice sheet expansion) consistently occurred during times of decreasing obliquity whereas mass ice wasting (ablation) events were consistently tied to minima in precession. Furthermore, our results suggest that the ubiquitous association between precession-driven mass wasting events and glacial termination is a distinct feature of the mid to late Pleistocene. Before then (increasing), obliquity alone was sufficient to end a glacial cycle, before losing its dominant grip on deglaciation with the southward extension of Northern Hemisphere ice sheets since ~1 Ma.
(Science. vol. 376, n° 0036-8075, pp. 961-967, 27/05/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
AMOC thresholds in CMIP6 models: NAHosMIP
The Atlantic meridional overturning circulation (AMOC) is an important part of our climate system, which keeps the North Atlantic relatively warm. It is predicted to weaken under climate change. The AMOC may have a tipping point beyond which recovery is difficult, hence showing quasi-irreversibility (hysteresis). Although hysteresis has been seen in simple models, it has been difficult to demonstrate in comprehensive global climate models. We present initial results from the North Atlantic hosing model intercomparison project, where we applied an idealised forcing of a freshwater flux over the North Atlantic in 9 CMIP6 models. The AMOC weakens in all models from the freshening, but once the freshening ceases, the AMOC recovers in some models, and in others it stays in a weakened state. We discuss how differences in feedbacks affect the AMOC response.
(27/05/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of volcanic eruptions in CMIP6 decadal prediction systems: a multi-model analysis
In recent decades three major volcanic eruptions of different intensity have occurred: Mount Agung (1963), El Chichón (1982) and Mount Pinatubo (1991), with reported climate impacts on seasonal-to-decadal timescales and providing a high prediction potential. The Decadal Climate Prediction Project component C (DCPP-C) includes a protocol to investigate the impact of such volcanic eruptions on decadal prediction, which consists in performing initialised sets of predictions just before the three historical volcanic eruptions, but in which the volcanic aerosol forcing is excluded. The impact of the volcanic eruptions is therefore determined by comparing these new forecasts with those included in the corresponding retrospective prediction experiment DCPP-A, which include historical volcanic aerosol forcing. Here we present the results from six CMIP6 decadal prediction systems (CanESM5, CESM1, EC-Earth3, HadGEM3, IPSL-CM6A and CMCC-CM2-SR5). The global mean temperature cooling is comparable among models and consistent with previous studies. The surface temperature response pattern in the first years is similar across all the models and for the individual volcanic eruptions. At later forecast times (years 6-9), differences among the models and eruptions emerge. Preliminary results show that the volcanic eruptions impact the atmospheric and oceanic dynamics, as shown in previous studies, although some differences across models emerge, specifically on the ocean overturning and gyre circulation changes.
(pp. EGU22-13395, 27/05/2022)
BSC-CNS, CMCC, MOHC, LOCEAN-VARCLIM, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, CCCma, ECCC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, NCAR