Environmentally relevant mixture of S-metolachlor and its two metabolites affects thyroid metabolism in zebrafish embryos
(Aquatic Toxicology. vol. 221, n° 0166-445X, pp. 105444, 01/04/2020)
UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS
Controls of local geology and cross-shore/longshore processes on embayed beach shoreline variability
10 Shoreline variability along the 3.6-km long Narrabeen Beach embayment in SE Australia is 11 investigated over a 5-year period. We apply the one-line shoreline change model LX-Shore, 12 which couples longshore and cross-shore processes and can handle complex shoreline 13 planforms, non-erodible emerged headlands and submerged rocky features. The model 14 skilfully reproduces the three dominant modes of shoreline variability, which are by 15 decreasing order of variance: cross-shore migration, rotation, and a third mode possibly 16 related to breathing. Model results confirm previous observations that longshore processes 17 primarily contribute to the rotation and third modes on the timescales of months to seasons, 18 while cross-shore processes control the shoreline migration on shorter timescales from hours 19 (storms) to months. Additional simulations simplifying progressively the bathymetry show 20 how the inherent geology strongly modulates the spatial modes of shoreline variability. The 21 offshore central rocky outcrop is found to limit the rotation. In contrast, the submerged rocky 22 platforms that extend from the headlands enhance the shoreline rotation mode and increase 23 alongshore variability of the cross-shore migration mode, owing to increased alongshore 24 variability in wave exposure. Offshore wave transformation across large-scale submerged 25 rocky features and headland shape are therefore critical to contemporary shoreline dynamics. 26 2
(Marine Geology. vol. 422, n° 0025-3227, pp. 106118, 01/04/2020)
MEDyC, URCA, URCA, CNRS, BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Last Abundant Appearance Datum of Hemidiscus karstenii driven by climate change
(Marine Micropaleontology. vol. 157, n° 0377-8398, pp. 101861, 30/03/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, AORI, UTokyo
The nature of deep overturning and reconfigurations of the silicon cycle across the last deglaciation
Changes in ocean circulation and the biological carbon pump have been implicated as the drivers behind the rise in atmospheric CO 2 across the last deglaciation; however, the processes involved remain uncertain. Previous records have hinted at a partitioning of deep ocean ventilation across the two major intervals of atmospheric CO 2 rise, but the consequences of differential ventilation on the Si cycle has not been explored. Here we present three new records of silicon isotopes in diatoms and sponges from the Southern Ocean that together show increased Si supply from deep mixing during the deglaciation with a maximum during the Younger Dryas (YD). We suggest Antarctic sea ice and Atlantic overturning conditions favoured abyssal ocean ventilation at the YD and marked an interval of Si cycle reorganisation. By regulating the strength of the biological pump, the glacial-interglacial shift in the Si cycle may present an important control on Pleistocene CO 2 concentrations.
(Nature Communications. vol. 11, n° 2041-1723, 24/03/2020)
CEN, CNRM, INSU - CNRS, CNRS, Comue de Toulouse, Fédération OSUG, UGA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, SUERC
Impact of model free parameters and sea-level rise uncertainties on 20-years shoreline hindcast: the case of Truc Vert beach (SW France)
Shoreline change is driven by various complex processes interacting at a large range of temporal and spatial scales, making shoreline reconstructions and predictions challenging and uncertain. Despite recent progress in addressing uncertainties related to the physics of sea-level rise, very little effort is made towards understanding and reducing the uncertainties related to wave-driven shoreline response. To fill this gap, 2 the uncertainties associated with the long-term modelling of shoreline change are analysed at a high-energy cross-shore transport dominated site. Using the state-of-the-art LX-Shore shoreline change model, we produce a probabilistic shoreline reconstruction, based on 3000 simulations over the past 20 years at Truc Vert beach, southwest France, whereby sea-level rise rate, depth of closure and three model free parameters are considered uncertain variables. We further address the relative impact of each source of uncertainty on the model results performing a Global Sensitivity Analysis. This analysis shows that the shoreline changes are mainly sensitive to the three parameters of the wave-driven model, but also that the sensitivity to each of these parameters is strongly modulated seasonally and interannually, in relation with wave energy variability, and depends on the time scale of interest. These results have strong implications on the model skill sensitivity to the calibration period as well as for the predictive skill of the model in a context of future climate change affecting wave climate and extremes.
(Earth Surface Processes and Landforms. vol. 45, n° 0197-9337, pp. 1895 - 1907, 15/03/2020)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Monorchis parvus and Gymnophallus choledochus: two trematode species infecting cockles as first and second intermediate host
Abstract The most deleterious stage of a trematode life cycle occurs in the first intermediate host where the parasite penetrates as a miracidium and asexually multiplicates in sporocysts or rediae. When infection advances, other organs can be occupied with severe effects on host individual health and population dynamics. Existing studies focused on these host/parasite systems are still scarce due to the usual low prevalence in ecosystems. Using cockles (Cerastoderma spp.) and two trematode species (Monorchis parvus and Gymnophallus choledochus) infecting these bivalves as first and second intermediate host, the present work aimed to (1) summarize the most relevant literature and (2) provide new information regarding this host/parasite system, taking advantage of a 21-year monthly database from Banc d'Arguin (France). This long-term monitoring showed that different trematode species display varying host size range preference (6–38 and 31–36 mm for M. parvus and G. choledochus, respectively). The occurrence of coinfection was lower than expected, raising some questions related to parasite interspecific competition. This review improved our understanding of the processes shaping the prevalence and distribution of parasitism. This study highlighted that beyond constant trematode assemblage monitoring, there is a need to identify the main predictors of rediae/sporocysts infection, such as the definitive host dynamics and miracidium infection processes, for future better management of host severe disease and mortality episodes.
(Parasitology, n° 0031-1820, pp. 1-16, 04/03/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of human activities on the spatio-seasonal dynamics of plankton diversity in drained marshes and consequences on eutrophication
(Water Research. vol. 170, n° 0043-1354, pp. 115287, 01/03/2020)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LIENSs, INSU - CNRS, ULR, CNRS, UNIMA
Backwash sediment record of the 2009 South Pacific Tsunami and 1960 Great Chilean Earthquake Tsunami
Following recent tsunamis, most studies have focused on the onshore deposits, while the offshore backwash deposits, crucial for a better understanding of the hydrodynamic processes during such events and offering an opportunity for sedimentary archives of past tsunamis, have mostly been omitted. Here, we present a unique sedimentary record of the backwash from two historical tsunamis sampled in a sheltered bay in American Samoa, namely the 2009 South Pacific Tsunami and the 1960 Great Chilean Earthquake Tsunami. Although not always concomitant with a marked grain size change, backwash deposits are identified by terrestrial geochemical and mineralogical signatures, associated with basal soft sediment micro-deformations. These micro-deformations, including asymmetric flame structures, are described for the first time in historic shallow marine backwash deposits and lead us to propose an improved depositional mechanism for tsunami backflow based on hyperpycnal currents. Moreover, this study brings a potential new criterion to the proxy toolkit for identifying tsunami backwash deposits, namely the basal soft sediment micro-deformations. We suggest that further studies focus on these micro-deformations in order to test the representability of this criterion for tsunami backwash deposits. Sheltered shallow marine environments in areas repeatedly impacted by tsunamis have a higher potential for the reconstruction of paleo-tsunami catalogs and should be preferentially investigated for coastal risk assessment.
(Scientific Reports. vol. 10, n° 2045-2322, pp. 4149, 01/03/2020)
LIENSs, INSU - CNRS, ULR, CNRS, UNSW, EDYTEM, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, URI, ANSTO
Tectonism and volcanism enhanced by deglaciation events in southern Iceland
(Quaternary Research. vol. 94, n° 0033-5894, pp. 94-120, 01/03/2020)
IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, LGO, UBS, IFREMER, UBO EPE, CNRS, iSTeP, INSU - CNRS, SU, CNRS, LGL-TPE, ENS de Lyon, UCBL, INSU - CNRS, UJM, CNRS, BRGM, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS