The dismantling of the Apulian carbonate platform during the late Campanian – early Maastrichtian in Albania
The Apulian carbonate margin is widely preserved across the Adriatic domain and has been extensively studied in the south of Italy. In Albania, Oligocene–Pliocene fold-and-thrust tectonics led to widespread exposure of the Apulian Platform and associated Ionian Basin carbonates. However, the portion linking the platform to the basin is missing, preventing a direct reconstruction of the platform margin. Syn-sedimentary folding and faulting are recognized in the uppermost part of both the platform and basinal/slope series. Mass transport deposits (MTDs) occur within the platform succession incorporated into well-bedded intertidal (stromatolites) to shallow-subtidal (rudist packstones) sedimentary sequences. They display significant lateral variability which is accompanied by both rigid and soft deformation structures. Spectacular slumps made up of sediment density flow deposits are recognized in the adjacent Ionian Basin. The lateral extent of basal shear surfaces, syn-sedimentary faults and folds evidenced in the Ionian Basin points toward multiple regional tectonic triggering events affecting the Apulian Platform margin at that time. Bio- and chrono-stratigraphic analyses suggest that the triggers occurred during the late Campanian – early Maastrichtian. Beyond the obvious interest from a stratigraphic point of view, the study of these events recording the dismantling of the Apulian carbonate platform allows for a better understanding of the triggering mechanisms and the sedimentary characteristics of MTDs and slumps at a basinal scale.
(Cretaceous Research. vol. 96, n° 0195-6671, pp. 83-106, 01/04/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Humans and their environment on the Médoc coastline from the Mesolithic to the Roman period
The northern coast of the Médoc between Soulac-sur-Mer and Montalivet-les-Bains has a rich archaeological heritage that is being directly impacted by coastal erosion. A series of clay-peat palaeosols that formed in ancient estuarine marshes holds evidence of intensive occupation from the Mesolithic until the end of the Roman period. Within this framework, our research focused on the two key sites of La Lède du Gurp (Grayan-et-l'Hôpital) and L'Amélie (Soulac-sur-Mer), where an interdisciplinary approach based on comparison of archaeological, sedimentary and palaeo-environmental data has made it possible to situate the main phases of occupation in their environmental context. This work has benefited from field documentation that is exceptionally well-preserved in wet sediments sealed beneath the present-day dune system. The most fleeting traces (animal tracks) like the sturdiest anthropic structures are preserved, as are many organic remains. These items provide access to first-rate documentation for reconstructing the range of activities practised in a specific ecosystem: salt production, livestock grazing, shellfish collecting, passage and carriage, and funerary and symbolic practices. Study of occupation over the long term reveals an alternating pattern of dynamic phases and decline phases that seem to be correlated with changes in the local environment.
(Quaternaire. vol. 30, n° 1142-2904, pp. 77-95, 01/04/2019)
UBM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, PRODIG, UP1, IRD, UP4, UPD7, CNRS, PACEA, UB, CNRS, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, SU, CNRS, UPCité, CReAAH, UM, UR, UR2, CNRS, UFR HHAA, UN, MC, LETG - Brest, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, HIPS, GEOLAB, UBP, IR SHS UNILIM, UNILIM, UCA [2017-2020], CNRS, UCA, PréTech, UPN, CNRS, TRACES, EHESS, UT2J, Comue de Toulouse, MCC, Inrap, CNRS
Intratidal and Fortnightly Variability of Vertical Mixing in a Macrotidal Estuary: The Gironde
Intratidal and fortnightly variability of turbulence at the mouth of a macrotidal estuary is explored in this study. Profiles of turbulent kinetic energy dissipation were estimated from a Vertical Microstructure Profiler, and velocity shear measurements and current velocities were collected with a vessel-mounted Acoustic Doppler Current Profiler. Gradient Richardson numbers were quantified using density measurements from a Conductivity, Temperature, Depth profiler and squared vertical shear quantified from current velocities. All measurements were collected over one complete semidiurnal tidal cycle in both neap and spring tide conditions. Vertical eddy viscosity (Az) was quantified from the available data and was used as a proxy for vertical mixing. Results showed intratidal asymmetries in bottom-generated turbulence during neap with Az larger during ebb tide (∼10−2 m2/s) than flood tide (∼10−3 m2/s) with the opposite occurring during spring tide with larger Az during flood (10−1 m2/s) than ebb (10−2 m2/s). Lateral processes produced elevated near-surface mixing decoupled from bottom-generated turbulence at the end of flood and ebb tide during neap and spring. The secondary flows were driven by Coriolis, and these flows either enhanced (neap tide, end of flood) or maintained (spring tide, end of ebb) total shear through slack tides producing near-surface to midwater column turbulence. These results are the first of their kind to show midwater column mixing from lateral circulation driven by Coriolis in a well-mixed system, which vary from the lateral processes previously shown to destabilize water columns in estuaries more influenced by stratification.
(Journal of Geophysical Research. Oceans. vol. 124, n° 2169-9275, pp. 2641-2659, 01/04/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Seasonal variation of transcriptomic and biochemical parameters of Donax trunculus related to its infection by Bacciger bacciger (trematode parasite)
(Estuarine, Coastal and Shelf Science. vol. 219, n° 0272-7714, pp. 291-299, 01/04/2019)
CESAM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The strength in numbers: comprehensive characterization of house dust using complementary mass spectrometric techniques
(Analytical and Bioanalytical Chemistry. vol. 411, n° 1618-2642, pp. 1957-1977, 01/04/2019)
NILU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UQ [All campuses : Brisbane, Dutton Park Gatton, Herston, St Lucia and other locations], INERIS, MMC, NTU
Occurrence, distribution and ecological risk of trace metals and organic pollutants in surface sediments from a Southeastern European river (Someşu Mic River, Romania)
In the present study, we investigated, for the first time, the distribution, sources and ecological risk of trace metals and organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in surface sediments from a Southeastern European river (Someşu Mic River, Romania). Concentrations of Cd, Cr, Cu, Pb, Ni and Zn ranged from 0.04 to 0.4, 9.4 to 43.15, 7.2 to 65.6, 12.3 to 131.4, 14.7 to 47.7 and 42.1 to 236.8 mg kg-1 dw, respectively. Concentrations of total PAHs, PCBs and OCPs ranged from 24.8 to 575.6, 2.7 to 252.7 and 2.1 to 44.3 ng g-1 dw, respectively. 2 Some sediment parameters, i.e., pH, total organic carbon (TOC) and total organic matter (OM) contents, played a significant role in the spatial distribution of contaminants. A combined analysis based on diagnostic ratios and multivariate analyses revealed PAHs originating mainly from pyrolytic sources. PCB compositions showed distinct contamination signatures for tri-to tetra-chlorinated PCBs, characteristic of contamination by Aroclor-1016 and-1254 technical mixtures. The dominant OCP congeners were α-HCH and p,p′-DDD, reflecting a past use of technical HCHs and DDTs in agricultural practices. Metal source and pollution status was assessed using geoaccumulation index and enrichment factor, which indicate a widespread pollution by Pb, Cd, Zn, Ni and Cu. The use of Sediments Quality Guidelines (SQGs), mean effect range-median quotient (m-ERM-Q) and toxic equivalent factor (TEF) indicated that the highest ecological risks occurred for PCBs and DDTs. This work presents not only initial baseline information on the extent of organic and inorganic contaminations in a river of ecological and economical interest, but also provides a diagnostic ratio/statistical combined approach that can be used to evaluate sediment quality in similar environments.
(Science of the Total Environment. vol. 660, n° 0048-9697, pp. 660-676, 01/04/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UCAR, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS
Fire on ice and frozen trees? Inappropriate radiocarbon dating leads to unrealistic reconstructions
(New Phytologist. vol. 222, n° 0028-646X, pp. 657-662, 01/04/2019)
UMR ISEM, Cirad, IRD, EPHE, PSL, UM, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UniPi, MTA, ELTE, ELTE, MTA, UCM
Potential of High-Resolution Pléiades Imagery to Monitor Salt Marsh Evolution After Spartina Invasion
An early assessment of biological invasions is important for initiating conservation strategies. Instrumental progress in high spatial resolution (HSR) multispectral satellite sensors greatly facilitates ecosystems' monitoring capability at an increasingly smaller scale. However, species detection is still challenging in environments characterized by a high variability of vegetation mixing along with other elements, such as water, sediment, and biofilm. In this study, we explore the potential of Pléiades HSR multispectral images to detect and monitor changes in the salt marshes of the Bay of Arcachon (SW France), after the invasion of Spartina anglica. Due to the small size of Spartina patches, the spatial and temporal monitoring of Spartina species focuses on the analysis of five multispectral images at a spatial resolution of 2 m, acquired at the study site between 2013 and 2017. To distinguish between the different types of vegetation, various techniques for land use classification were evaluated. A description and interpretation of the results are based on a set of ground truth data, including field reflectance, a drone flight, historical aerial photographs, GNSS and photographic surveys. A preliminary qualitative analysis of NDVI maps showed that a multi-temporal approach, taking into account a delayed development of species, could be successfully used to discriminate Spartina species (sp.). Then, supervised and unsupervised classifications, used for the identification of Spartina sp., were evaluated. The performance of the species identification was highly dependent on the degree of environmental noise present in the image, which is season-dependent. The accurate identification of the native Spartina was higher than 75%, a result strongly affected by intra-patch variability and, specifically, by the presence of areas with a low vegetation density. Further, for the invasive Spartina anglica, when using a supervised classifier, rather than an unsupervised one, the accuracy of the classification increases from 10% to 90%. However, both algorithms highly overestimate the areas assigned to this species. Finally, the results highlight that the identification of the invasive species is highly dependent both on the seasonal presence of itinerant biological features and the size of vegetation patches. Further, we believe that the results could be strongly improved by a coupled approach, which combines spectral and spatial information, i.e., pattern-recognition techniques.
(Remote Sensing. vol. 11, n° 2072-4292, pp. 968, 01/04/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, IMS, UB, CNRS
Sub-lethal effects of waterborne copper in early developmental stages of rainbow trout (Oncorhynchus mykiss)
The aim of this work was to study the impact of copper during a sub-chronic exposure to environmental concentrations in the early life stages of rainbow trout (Oncorhynchus mykiss). Eyed-stage embryos of rainbow trout, at 265°D, were exposed in semi-static conditions to sublethal concentrations of CuSO4 up to the larval stage (528 °D) under laboratory-controlled conditions. During 3 weeks, they were exposed to the environmentally-realistic concentration of 2 µg/L Cu and to a 10-fold higher concentration, 20 µg/L Cu. Several biological (survival, hatching success, malformation, growth) and behavioral (swimming activity) and molecular endpoints (genotoxicity and gene transcription) were studied. Exposure to 20 µg/L Cu had an inhibitory effect on hatching and increased half-hatched embryos (25%). At the end of the exposure, no significant differences were observed in growth of the larvae exposed to the highest Cu concentration. However, larvae exposed to 2 µg/L Cu exhibited increased growth in comparison with non-exposed larvae. The percentage of malformed larvae was significantly higher for both copper conditions, with skeletal malformations being the most observed. Expression of several genes was evaluated in whole larvae using quantitative real-time PCR. Genes involved in detoxification (gst, mt1 and mt2) and in cell cycle arrest (p53) were significantly repressed in both copper conditions when compared to control. In addition, potential genotoxic effects on larvae were investigated by the comet assay on blood cells, but this test did not demonstrate any significant DNA damage on larvae exposed to copper. This study confirms the adverse effects of copper on early life stages of rainbow trout even at the lowest environmentally relevant tested concentration.
(Ecotoxicology and Environmental Safety. vol. 170, n° 0147-6513, pp. 778-788, 01/04/2019)
LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, UB
In vitro simulation of oscillatory redox conditions in intertidal sediments: N, Mn, Fe, and P coupling
In coastal environments, oscillating redox conditions represent a functional state affecting organic matter mineralization. Such transient diagenetic processes remain difficult to study in situ, and we therefore designed a specific reactor to provide experimental results that are environmentally relevant in this context. Here, we present the results of two independent experiments carried out with sediment having contrasting Fe, Mn contents, collected from a coastal tidal lagoon (the Arcachon bay) and a mesotidal estuary (Adour river). Sediment and overlying water were mixed to form slurries that were submitted to redox oscillations to assess the diagenetic mechanisms that affect N, P, Fe, Mn, and S. Changing from anoxic to oxic conditions, we observed a rapid oxidation of dissolved Fe(II) and dissolved inorganic phosphorus (DIP) was apparently trapped by the newly formed Fe-oxyhydroxides (Fe-ox). DIP was totally titrated in the coastal lagoon sediment, but not in estuarine sediment, where the initial amount of Fe available was lower. In both experiments, Mn(II) was only slowly oxidized during the oxidation events and a major part of Mn(II) was adsorbed on new Fe-ox. In coastal lagoon sediment, ammonium remained constant in oxic conditions while nitrate was produced from organic-N mineralization. On the contrary, in estuarine sediment, ammonium was quantitatively oxidized to nitrate. When the conditions became anoxic again, direct reduction of nitrate to ammonium occurred in coastal lagoon sediment. Anaerobic production of nitrate occurred in estuarine sediment, probably because Mn-oxides (Mn-ox), which had a high concentration, acted as an oxidant for ammonium. Consequently, nitrate production prevented Fe(II) accumulation. The Mn-N-Fe coupling outlined here is an apparent indirect oxidation of Fe(II) by Mn-ox through anaerobic nitrification (with Mn-ox) and denitrification (with Fe-ox). This coupling also implied P availability because of the strong control of P by Fe. These experimental results show that nutrient dynamics in oscillatory redox environments such as the estuarine turbidity zone, bioturbated sediment, or tidal permeable sediments highly depends on Mn-and Fe-ox availability.
(Continental Shelf Research. vol. 177, n° 0278-4343, pp. 33-41, 01/04/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA