ANR COYOTES project (Comoros & maYotte: vOlcanism, TEctonics and Seismicity)
In order to understand the unprecedented underwater telluric event of the Mayotte Seismo-Volcanic (MSV) crisis (2018-2020), it appears essential to reach a critical level of knowledge on the evolution of the seismicity, volcanic activity and geodetic deformation, but also on the geodynamic context. This includes the kinematics and the characterization of the lithospheric and crustal structures, on both short- and long-term and regional and local scales. Towards this goal, the COYOTES project aims to better understand the regional geodynamic and geological context of the north Mozambique Channel. The objectives are to understand the distribution of active and recent deformations around the Comoros Archipelago, in particular the Mayotte Island, to image the crustal structuration and to study the recent tectono-sedimentary evolution. Both the link with the East African rift system and the role of Mesozoic inherited structures in the spatial distribution of present-day deformation associated to the MSV crisis will be investigated. This updated geodynamic and geological knowledge will be used to improve the assessment of the volcanic and seismic hazards. The main work-packages are 1) Current seismic sequence, deformation and kinematics; 2) Recent and active volcanism and tectonics in the Comoros archipelago; 3) Long-term geodynamics: Regional structuration and inheritance. It will integrate new onshore and offshore acquisitions of geological and geophysical data, their interpretation as well as modelling. The COYOTES project (2020-2024) is funded by the French National Research Agency (ANR), involving three thesis, one post-doc and more than 40 scientists from the BRGM, IPGS/EOST, IPGP, IsTep, ENS, La Réunion University, EPOC, Ifremer, SHOM, GEOPS, LMV, GET, ISTO, OVPF, ... (http://www.geocean.net/coyotes/doku.php?id=start). The project is linked with the SISMAORE oceanographic campaign that will occur on the R/V Pourquoi Pas? from December 2020 to February 2021. [@https://agu.confex.com/agu/fm20/webprogram/Paper680395.html]
(01/12/2020)
BRGM, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, iSTeP, INSU - CNRS, SU, CNRS, LGSR, UR, IPG Paris, IPGS, UNISTRA, INSU - CNRS, CNRS, LMV, IRD, INSU - CNRS, UJM, UCA [2017-2020], CNRS, LGENS, INSU - CNRS, CNRS, ENS-PSL, PSL, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS, GM, IFREMER, EOST, UNISTRA, INSU - CNRS, CNRS, LMV, IRD, INSU - CNRS, CNRS, UCA, GEOPS, INSU - CNRS, CNRS, ITES, ENGEES, UNISTRA, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Applications and innovations in polar marine diatom analysis
(Marine Micropaleontology. vol. 161, n° 0377-8398, pp. 101939, 01/12/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Multi- and transgenerational effects following early-life exposure of zebrafish to permethrin and coumarin 47: Impact on growth, fertility, behavior and lipid metabolism
Transgenerational effects induced by environmental stressors are a threat to ecosystems and human health. However, there is still limited observation and understanding of the potential of chemicals to influence life outcomes over several generations. In the present study, we investigated the effects of two environmental contaminants, coumarin 47 and permethrin, on exposed zebrafish (FO) and their progeny (F1-F3). Coumarin 47 is commonly found in personal care products and dyes, whereas permethrin is used as a domestic and agricultural pyrethroid insecticide/insect repellent. Zebrafish (F0) were exposed during early development until 28 days post-fertilization and their progeny (F1-F3) were bred unexposed. On one hand, the effects induced by coumarin 47 suggest no multigenerational toxicity. On the other hand, we found that behavior of zebrafish larvae was significantly affected by exposure to permethrin in F1 to F3 generations with some differences depending on the concentration. This suggests persistent alteration of the neural or neuromuscular function. In addition, lipidomic analyses showed that permethrin treatment was partially correlated with lysophosphatidylcholine levels in zebrafish, an important lipid for neurodevelopment. Overall, these results stress out one of the most widely used pyrethroids can trigger long-term, multi- and possibly transgenerational changes in the nervous system of zebrafish. These neurobehavioral changes echo the effects observed under direct exposure to high concentrations of permethrin and therefore call for more research on mechanisms underlying effect inheritance.
(Ecotoxicology and Environmental Safety. vol. 205, n° 0147-6513, pp. 111348, 01/12/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UFZ, GABI, INRAE
AQUAVIT Quand les plantes aquatiques invasives transcendent les frontières des lacs aquitains
Le projet de recherche AquaVIT vise à accompagner l'évolution des modalités de gestion des grands lacs aquitains confrontés à des enjeux environnementaux liés aux colonisations par les plantes aquatiques invasives.
(pp. 4 p., 01/12/2020)
UR ETBX, INRAE, UR EABX, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Physical properties of epilithic river biofilm as a new lead to perform pollution bioassessments in overseas territories
Chlordecone (CLD) levels measured in the rivers of the French West Indies were among the highest values detected worldwide in freshwater ecosystems, and its contamination is recognised as a severe health, environmental, agricultural, economic, and social issue. In these tropical volcanic islands, rivers show strong originalities as simplified food webs, or numerous amphidromous migrating species, making the bioindication of contaminations a difficult issue. The objective of this study was to search for biological responses to CLD pollution in a spatially fixed and long-lasting component of the rivers in the West Indies: the epilithic biofilm. Physical properties were investigated through complementary analyses: friction, viscosity as well as surface adhesion were analyzed and coupled with measures of biofilm carbon content and exopolymeric substance (EPS) production. Our results have pointed out a mesoscale chemical and physical reactivity of the biofilm that can be correlated with CLD contamination. We were able to demonstrate that epilithic biofilm physical properties can effectively be used to infer freshwater environmental quality of French Antilles rivers. The friction coefficient is reactive to contamination and well correlated to carbon content and EPS production. Monitoring biofilm physical properties could offer many advantages to potential users in terms of effectiveness and ease of use, rather than more complex or time-consuming analyses. Out of the 11,435 French water bodies analysed for quality compliance according to regulations imposed by European legislation, 10% are located between the tropics and the equator, thousands of kilometres away from European shores 1. In the outermost tropical territories, climatic characteristics often result in highly turbulent tropical streams 2 that support simplified ecosystems with very few primary producers. Due to high river flow, perennial phytoplankton, zooplankton and macroalgae are scarce or missing and the epilithic biofilm deserves here, even more than elsewhere, the comparison with a real productive and contributive "microbial skin" 3. The epilithic biofilm is the only endogenous long-lasting primary producer that grows on submersed river stones and is largely exploited as a food source by all diadromous fish or crustaceans 4,5. In these countries, the simplified food webs and the massive flows of post-larvae and juveniles regularly re-entering the rivers and migrating
(Scientific Reports. vol. 10, n° 2045-2322, pp. 17309, 01/12/2020)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, ISYEB, MNHN, EPHE, PSL, SU, CNRS, UA, DGD.REVE, MNHN, MNHN, C3MAG, UA, GTSI, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UPPA, IPREM, UPPA, INC-CNRS, CNRS, CNRS
Magnetic fabric of Bengal fan sediments: Holocene record of sedimentary processes and turbidite activity from the Ganges-Brahmaputra river system
We present here a study based on the Anisotropy of Magnetic Susceptibility (AMS) and magnetic mineralogy carried out on the composite core MD17&18taken from the eastern levee of the active channel of the middle Bengal Fan in the Indian Ocean. Based on C-14 dating, the sedimentary sequence covers 9.8 ka in 39 m of sediment. It therefore records at very high resolution the variations in continental material exported to the ocean by the Ganges-Brahmaputra river system during the Holocene.This sequence was divided into two units according to turbidite activity: Unit 1 from 9.8 to 9.2 ka cal. BP representing 39 m of coarse-grained turbidite sequences (coarse silts to fine sands) and extremely high sedimentation rates. Unit 2 of 9.2 ka cal. BP to the present characterized by a sharp decrease in the sedimentation rate, the presence of fine-grained turbidites characterized by strong decrease in the ln(Ti/Ca) ratio.Our AMS results indicate that the magnetic fabric is highly sensitive to the mode of deposition. The turbidite sequences are clearly characterized by very high F and Pj values, not only of the coarse-grained turbidite levels in unit 1, but also of the fine turbidites in unit 2. We suggest that this strong degree of anisotropy is the result of the strong and rapid deposition during the turbidite sequences which induces an additional compaction effect.Furthermore, low temperature SIRM measurements revealed that the magnetic minerals representative of the Ganges and Brahmaputra drainage area are magnetite, hematite and goethite. A higher supply in fine-grained magnetite was observed during the turbidite sequences in phase with an increase in sediment grain size.
(Marine Geology. vol. 430, n° 0025-3227, pp. 106347, 01/12/2020)
LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, PSL, UVSQ, CEA, INSU - CNRS, X, IP Paris, CNES, SU, CNRS, UPCité, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOPS, INSU - CNRS, CNRS, CR2P, MNHN, SU, CNRS, iSTeP, INSU - CNRS, SU, CNRS, CEREGE, IRD, AMU, CdF (institution), INSU - CNRS, CNRS, INRAE, IPGP - UMR_7154, INSU - CNRS, IGN, UR, IPG Paris, CNRS, UPCité, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Blind testing of shoreline evolution models
Beaches around the world continuously adjust to daily and seasonal changes in wave and tide conditions, which are themselves changing over longer timescales. Different approaches to predict multi-year shoreline evolution have been implemented; however, robust and reliable predictions of shoreline evolution are still problematic even in short-term scenarios (shorter than decadal). Here we show results of a modelling competition, where 19 numerical models (a mix of established shoreline models and machine learning techniques) were tested using data collected for tairua beach, new Zealand with 18 years of daily averaged alongshore shoreline position and beach rotation (orientation) data obtained from a camera system. in general, traditional shoreline models and machine learning techniques were able to reproduce shoreline changes during the calibration period (1999-2014) for normal conditions but some of the model struggled to predict extreme and fast oscillations. During the forecast period (unseen data, 2014-2017), both approaches showed a decrease in models' capability to predict the shoreline position. this was more evident for some of the machine learning algorithms. A model ensemble performed better than individual models and enables assessment of uncertainties in model architecture. Research-coordinated approaches (e.g., modelling competitions) can fuel advances in predictive capabilities and provide a forum for the discussion about the advantages/disadvantages of available models. Quantitative prediction of beach erosion and recovery is essential to planning resilient coastal communities with robust strategies to adapt to erosion hazards. Over the last decades, research efforts to understand and predict shoreline evolution have intensified as coastal erosion is likely to be exacerbated by climatic changes 1-5. The social and economic burden of changes in shoreline position are vast, which has inspired development of a growing variety of models based on different approaches and techniques; yet current models can fail (e.g. predicting erosion in accreting conditions). The challenge for shoreline models is, therefore, to provide reliable, robust and realistic predictions of change, with a reasonable computational cost, applicability to a broad variety of systems, and some quantifiable assessment of the uncertainties.
(Scientific Reports. vol. 10, n° 2045-2322, 01/12/2020)
CNRS, SBMS, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, WRL, UNSW
Quantitative assessments of moisture sources and temperature governing rainfall δ18O from 20 years' monitoring records in SW-France: Importance for isotopic-based climate reconstructions
(Journal of Hydrology. vol. 591, n° 0022-1694, pp. 125327, 01/12/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, I2M-BX, UB, CNRS, INRAE, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEOTRAC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
An Invasive Mussel (Arcuatula senhousia, Benson 1842) Interacts with Resident Biota in Controlling Benthic Ecosystem Functioning
The invasive mussel Arcuatula senhousia has successfully colonized shallow soft sediments worldwide. This filter feeding mussel modifies sedimentary habitats while forming dense populations and efficiently contributes to nutrient cycling. In the present study, the density of A. senhousia was manipulated in intact sediment cores taken within an intertidal Zostera noltei seagrass meadow in Arcachon Bay (French Atlantic coast), where the species currently occurs at levels corresponding to an early invasion stage. It aimed at testing the effects of a future invasion on (1) bioturbation (bioirrigation and sediment mixing) as well as on (2) total benthic solute fluxes across the sediment-water interface. Results showed that increasing densities of A. senhousia clearly enhanced phosphate and ammonium effluxes, but conversely did not significantly affect community bioturbation rates, highlighting the ability of A. senhousia to control nutrient cycling through strong excretion rates with potential important consequences for nutrient cycling and benthic-pelagic coupling at a broader scale. However, it appears that the variability in the different measured solute fluxes were underpinned by different interactions between the manipulated density of A. senhousia and several faunal and/or environmental drivers, therefore underlining the complexity of anticipating the effects of an invasion process on ecosystem functioning within a realistic context.
(Journal of Marine Science and Engineering. vol. 8, n° 2077-1312, pp. 963, 26/11/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Label free imaging with harmonic generation microscopy and endogeneous fluorescence investigations for food, ecotoxicology and health issues
(24/11/2020)
PAnTher, ONIRIS, INRAE, APEX, PAnTher, ONIRIS, INRAE, ONIRIS, GEPEA-MAPS2, GEPEA, IUT Nantes, UN, UN UFR ST, UN, IUT Saint-Nazaire, UN, EPUN, UN, ONIRIS, CNRS, UBL, IMT Atlantique, IMT, IUT La Roche-sur-Yon, UN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS