Sensibilité des stades précoces de l'esturgeon sterlet à des concentrations environnementales de deux fongicides : le boscalid et l'imazalil
(11/05/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, INRAE
Peer Community In… A free recommendation process of preprints based on peer reviews
Les Peer Community In… (PCI, https://peercommunityin.org/) sont des communautés scientifiques qui organisent des processus éditoriaux de science ouverte. Il s'agit de communautés spécialisées effectuant une évaluation scientifique par les pairs et à la demande des auteurs, de preprints déposés sur des serveurs de preprints ou des archives ouvertes institutionnelles. Dans chaque PCI, les recommandeurs, qui sont les équivalents des éditeurs scientifiques de revues, constituent une équipe de reviewers qui réalisent une évaluation détaillée de l’article. S’ensuit une décision éditoriale qui mène soit au rejet, soit à la demande de corrections, soit à la validation de l’article scientifique, éventuellement après plusieurs rounds d'évaluation. Dans ce dernier cas, le recommandeur écrit un texte de recommandation dans lequel il explique pourquoi il a validé l’article. L’ensemble de la communauté scientifique a ainsi accès gratuitement au contenu validé de l'article et aux évaluations/recommandations. La publication dans les PCI est de plus en plus reconnue par les instances d’évaluation.
(Webinaires de la Fédération FIRE, pp. https://www.canal-u.tv/chaines/fire/christian-mougin-l-initiative-peer-community-in, 11/05/2022)
ECOSYS, INRAE, FIRE, MNHN, IRD, SU, CNRS, UPCité, INRAE, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR CBGP, Cirad, IRD [Occitanie], INRAE, Institut Agro, UM, ISA, UNS, CNRS, INRAE, UniCA, DipSO, INRAE
Sensitivity of newly transformed juveniles of the freshwater pearl mussel: Margaritifera margaritifera to acute toxicity of a wide range of contaminants
The freshwater pearl mussel (FWPM) Margaritifera margaritifera is a bivalve mollusk critically endangered in Europe. There is a special concern about the conservation of this species, but little is known about its sensitivity to environmental pollution. Here, acute toxicity tests were conducted at 16°C according to a standard guide for conducting toxicity tests on freshwater mussels (ASTM international E2455), in order to assess toxicity thresholds for arsenic (As), aluminum (Al), cadmium (Cd), copper (Cu), nickel (Ni), nitrates (NO3−), and orthophosphates (PO43−) on newly transformed juveniles of M. margaritifera. The comparison with toxicity data for other newly transformed freshwater mussel juveniles from the same family and superfamily, Margaritiferidae and Unionidae, showed that FWPM juveniles were the most sensitive species to NO3−, among the most sensitive species to Ni, the least sensitive species to Cd, and showed an intermediate sensitivity to Cu compared to other freshwater mussels. This study is the first to provide toxicity thresholds for several pollutants on newly transformed juveniles of the FWPM. This brings new knowledge on its sensitivity to environmental pollution that could be helpful data for conservation strategies and these findings represent the first window for further complex studies.
(Hydrobiologia. vol. 849, n° 0018-8158, pp. 2029-2041, 01/05/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Metals and metalloids concentrations in three genotypes of pelagic Sargassum from the Atlantic Ocean Basin-scale
Since 2011, in Caribbean Islands, unprecedented massive stranding of a pelagic brown algae Sargassum spp. has damaged coastal ecosystems and disrupted the economy. Brown algae have a high capacity to concentrate heavy metals contaminants. Through accumulation of heavy metals during their journey, floating Sargassum can play a role of contaminant transfer from off shore to the coast. In July and August 2019, three morphotypes of sargasso (S. fluitans III, S. natans I and S. natans VIII) were sampled in seven stations, regularly spaced, along a 3,400 km transect from the middle of Atlantic Ocean to Guadeloupe Islands (French West Indies). For each of the 72 samples of sargasso algae, concentrations of 15 heavy metal(loid)s elements were analyzed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Mean metal concentrations in all morphotypes and stations were ranked in the following descending order: As > Fe > Al > Mn > Cd > Zn > Ni > V > Cu > Cr > Hg. The metalloid As is the most largely present in all our samples with a mean concentration of 92.72 μg.g −1 and an maximum value of 115 μg. g −1 which is in accordance with concentrations previously observed in the Caribbean area (80-150 ppm). Those value are above different maximum safety level, therefore, strategies proposed for valorization of Sargassum should consider this As content to avoid potential environmental and health issues. At the scale of the Atlantic Ocean, metallic element concentration do not present spatial longitudinal gradient. Morphotype of Sargassum present different metal(loids) contamination patterns with distinction between S. fluitans III and the two others morphotypes (S. natans I and VIII).
(Marine Pollution Bulletin. vol. 178, n° 0025-326X, pp. 113564, 01/05/2022)
ISYEB, MNHN, EPHE, PSL, SU, CNRS, UA, ULaval, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IBED, UvA
Historical mass balance of cadmium decontamination trends in a major European continent-ocean transition system: Case study of the Gironde Estuary
Despite the effective remediation efforts following the end of the metallurgic activity thirty years ago upstream the Lot River watershed, the levels of cadmium (Cd) accumulated in wild oysters from the downstream Gironde Estuary still exceed nowadays the admissible human consumption limit (5 mg/kg, d.w.). The main goal of this work is to quantify the role of sediments as long-term intra-estuarine sources or sinks of Cd and the transport of this contaminant towards the estuary mouth taking as case study the example of the highly turbid Gironde Estuary. The original estimation for the annual net fluxes of the suspended particulate matter (FnetSPMyear) and particulate Cd (FnetCdpyear) presented in this work between 1990 and 2020 indicates that 80% of the Cd discharged into the ocean is in dissolved form (Cdd). The values of FnetCdpyear vary proportionally to those of FnetSPMyear and ranged between 0.1 and 1.4 t/y, with a ten-year average decreasing from 0.8 to 0.6 t/y for the past 30 years. The differences between ten-year total (Cdp + Cdd) gross and net fluxes show that Cd has effectively been stored in estuarine sediments. This Cd storage was of about 43, 22 and 13 t for the 1990s, 2000s and 2010s, respectively. However, during years of low gross fluxes, estuarine sediments act as additional, secondary sources of bio-available/dissolved Cd into the water column, potentially relating to the continued observations of high Cd concentrations in wild oysters at the estuary mouth. In addition to the natural solubility of Cdp along the salinity and turbidity gradients of the estuary, natural and anthropogenic remobilization of bottom sediment particles further contribute to its mobilization from the particle phase, along with other numerous inorganic/organic pollutants. The mass balances presented in this work could support a new sediment management policy potentially more beneficial to the estuarine ecosystem.
(Marine Environmental Research. vol. 176, n° 0141-1136, 01/04/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Asian-Australian monsoon evolution over the last millennium linked to ENSO in composite stalagmite δ18O records
The Asian-Australian monsoon (AAM) system distinctly influences global climate. However, the linkage between ENSO (El Niño–Southern Oscillation) and AAM is still poorly understood over the last millennium. Here, we combined stalagmite δ18O (δ18Os) records with exceptionally high-resolution and high-precision chronologies to demonstrate a tight remote coupling between AAM and tropical ocean hydrology on the multi-year, decadal, and centennial timescales. Our results reveal that (1) There is a significant negative correlation between the multi-year weighted average precipitation δ18O (δ18Oaw) from the AAM and Southern Oscillation Index (SOI), providing a modern analogous coupling for linking stalagmite δ18O (δ18Os) and ENSO over the past 100 years. (2) Over the last millennium, the integrated δ18Os record exhibit positive excursions during the Little Ice Age (LIA), marked by a tendency for more El Niño-like state conditions in the tropical Pacific, which is consistent in SST-gradient ENSO reconstruction but different to precipitation reconstruction. (3) Wavelet and power spectrum analysis for the integrated δ18Os record in the AAM region show that there is a significant multi-year periodicity (2.2, 2.8, 3.5, 4.6 yr), conceding with the ENSO cycle (2–7 yr), whereas, some multi-decadal and centennial cycles (10.1, 17, 28.6, 52.7, 143 yr) are significant too. We provide evidence from instrumental and paleocliamte datasets (GNIP and NOAA) and propose a possible “circulation effect” mechanism responsible for variations of δ18Os in the East Asian Monsoon (EAM) and Australian Monsoon (AM) region over the last millennium.
(Quaternary Science Reviews. vol. 281, n° 0277-3791, 01/04/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Pesticide toxicity towards microalgae increases with environmental mixture complexity
Effect-directed analysis (EDA) aims at identifying the compound(s) responsible for toxicity in a complex environmental sample where several dozens of contaminants can be present. In this study, we used an environmental mixture extracted from the Polar Organic Chemical Integrative Sampler (POCIS) previously immersed downstream a landfill (River Ponteils, South West France), to perform an EDA approach using a microalgal bioassay based on the photosynthetic capacities of diatom (Nitzschia palea) cultures. Adverse effects on photosynthetic capacities were recorded when algae were exposed to the entire POCIS extract (> 85% inhibition at the highest concentration tested). This result was coherent with the detection of diuron and isoproturon, which were the 2 most concentrated herbicides in the extract. However, the EDA process did not allow pointing out the specific compound(s) responsible for the observed toxicity but rather suggested that multiple compounds were involved in the overall toxicity and caused mixture effects.
(Environmental Science and Pollution Research. vol. 29, n° 0944-1344, pp. 29368-29381, 01/04/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, INRAE
ESCROpath , a Bayesian mixing model to quantify diets and trophic flows in aquatic food webs
Food-web modelling is a key tool to provide a global and comprehensive knowledge on community structure, biodiversity and ecosystem processes and functioning. In particular, it allows computing integrative and holistic indices describing food web characteristics, topology and functioning. However, one of the main sources of uncertainty in most food-web models is the estimation of diet matrices. In the present work, we propose an innovative approach that combines (a) a Bayesian mixing model using both isotopes and contaminants as chemical tracers with (b) classical mass-balance equations. This dual approach allows the simultaneous estimation of diet composition, isotopic enrichment, contaminant biomagnification, and contaminants and biomass flows in the whole food web. This original model named ESCROpath also provides food-web indices derived from ecological network analysis (ENA). As a case study, the approach was implemented in the Gironde estuarine food web (SW France) for which isotopes, contaminants and trophic data exist. Two sets of priors were constructed accounting for more or less uncertainty in trophic parameter estimates. Outputs were compared with previous published Ecopath results. A constrained calibration led to very similar outputs as Ecopath (which shows that the method is able to find the initial set of parameters if it is forced to do so), whereas a free calibration led to slight differences in trophic parameters and ENA indice estimations (which shows that the Ecopath solution was not fully optimal). Quite different diet matrices and estimations of flows distribution within the food web can thus be obtained. ESCROpath is an original flexible food-web modelling tool that, for the first time, makes it possible to go from a model mainly built on an ‘estimate’ of the parameters based on expert knowledge (which constitutes the main criticism formulated against Ecopath) to a statistical Bayesian framework for the estimation of the trophic parameters. It thus provides a very integrated framework for food-web modelling by estimating simultaneously trophic parameters, diet compositions and trophic enrichment/magnification factors. By doing this, it notably provides reliable and robust uncertainty estimations for output parameters.
(Methods in Ecology and Evolution. vol. 13, n° 2041-210X, pp. 894-907, 01/04/2022)
UR EABX, INRAE, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], IRSTEA, DECOD, IFREMER, INRAE, Institut Agro, Institut Agro, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Bioaccumulation of Per and Polyfluoroalkyl Substances in Antarctic Breeding South Polar Skuas (Catharacta maccormicki) and Their Prey
Per and polyfluoroalkyl substances (PFASs) are found in Antarctic wildlife, with high levels in the avian top predator south polar skua ( Catharacta maccormicki ). As increasing PFAS concentrations were found in the south polar skua during the breeding season in Antarctica, we hypothesised that available prey during the breeding period contributes significantly to the PFAS contamination in skuas. To test this, we compared PFAS in south polar skuas and their main prey from two breeding sites on opposite sides of the Antarctic continent: Antarctic petrel ( Thalassoica antarctica ) stomach content, eggs, chicks, and adults from Svarthamaren in Dronning Maud Land and Adélie penguin chicks ( Pygoscelis adeliae ) from Dumont d’Urville in Adélie Land. Of the 22 PFAS analysed, seven were present in the majority of samples, except petrel stomach content [only perfluoroundecanoate (PFUnA) present] and Adélie penguins (only four compounds present), with increasing concentrations from the prey to the skuas. The biomagnification factors (BMFs) were higher at Dumont d’Urville than Svarthamaren. When adjusted to reflect one trophic level difference, the BMFs at Svarthamaren remained the same, whereas the ones at Dumont d’Urville doubled. At both the colonies, the skua PFAS pattern was dominated by perfluorooctanesulfonic acid (PFOS), followed by PFUnA, but differed with the presence of branched PFOS and perfluorotetradecanoate (PFTeA) and lack of perfluorononanoate (PFNA) and perfluorodecanoate (PFDA) at Dumont d’Urville. At Svarthamaren, the pattern in the prey was comparable to the skuas, but with a higher relative contribution of PFTeA in prey. At Dumont d’Urville, the pattern in the prey differed from the skuas, with the domination of PFUnA and the general lack of PFOS in prey. Even though the PFAS levels are low in Antarctic year-round resident prey, the three lines of evidence (pattern, BMF difference, and BMF adjusted to one trophic level) suggest that the Antarctic petrel are the significant source of PFAS in the Svarthamaren skuas, whereas the skuas in Dumont d’Urville have other important sources to PFAS than Adélie penguin, either in the continent or external on the inter-breeding foraging grounds far from Antarctica.
(Frontiers in Marine Science. vol. 9, n° 2296-7745, 31/03/2022)
UiO, NILU, CEBC, ULR, CNRS, INRAE, LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IUF, M.E.N.E.S.R., NMBU
Les nutriments dans les écosystèmes côtiers : évolution à long terme, forçages du changement global et conséquence sur la biomasse et la diversité du phytoplancton
Du fait de leur position à l’interface entre les écosystèmes continentaux, les écosystèmes océaniques et l’atmosphère, les écosystèmes côtiers sont soumis à de nombreuses pressions et sont particulièrement sensibles aux perturbations. En effet, ils sont un lieu important pour de nombreux processus biogéochimiques et comptent parmi les zones les plus productives de la planète. Ainsi, étudier l’évolution des écosystèmes côtiers au travers des prismes des concentrations en nutriments et de la structure des communautés phytoplanctoniques devient intéressant et indispensable afin de comprendre l’impact du changement global sur ces écosystèmes. Les pressions qu’ils subissent sont en grande partie d’origine naturelle, mais, au cours du dernier siècle, ces dernières ont été modifiées en nombre, en intensité et en magnitude par les activités de l’homme. En effet, les pratiques agricoles et industrielles ont engendré une augmentation des apports nutritifs dans les écosystèmes côtiers. L’augmentation de la température, couplée aux perturbations des régimes des vents et des précipitations, a entrainé des modifications des échanges entre les écosystèmes côtiers et les compartiments voisins (continent, océan, sédiment, atmosphère). Afin de déterminer l’influence du changement global sur les écosystèmes côtiers, cette thèse se base sur des services d’observation français (SOMLIT, REPHY), au travers de 29 stations réparties dans 11 écosystèmes sur les 3 façades maritimes françaises. Des données d’apports continentaux et de la variation climatique locale et régionale ont été couplées aux mesures in-situ et considérées comme données forçantes. Les relations entre les forçages environnementaux et les écosystèmes côtiers ont été étudiées au travers d’un panel d’analyses statistiques univariées et multivariées.Il en ressort que les écosystèmes côtiers français présentent une grande diversité de caractéristiques (statut trophique, habitat, climat, apports continentaux…) et que cette diversité permet de différencier spatialement les écosystèmes. Cependant, leurs évolutions temporelles, étudiées au travers de 3 prismes (concentrations en nutriments, structures taxonomique et fonctionnelle des communautés phytoplanctoniques), ont permis de grouper certains écosystèmes entre eux, en fonction de leurs caractéristiques, selon l’approche considérée. Certains écosystèmes se sont démarqués en montrant des évolutions opposées au schéma général détecté (e.g. vers une diminution des concentrations en nutriments).Cela met en lumière le caractère dynamique et la complexité des écosystèmes côtiers, bien que les écosystèmes côtiers français soient situés dans une zone géographique limitée.
(31/03/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS