Active tectonics of the Calabrian subduction revealed by new multi-beam bathymetric data and high-resolution seismic profiles in the Ionian Sea (Central Mediterranean)
The detailed morphology and internal structure of the Calabrian accretionary wedge and adjacent Eastern Sicily margin are imaged in unprecedented detail by a combined dataset of multi-beam bathymetry and high-resolution seismic profiles. The bathymetric data represent the results of 6 recent marine geophysical surveys since 2010 as well as a compilation of earlier surveys presented as a 2 arc-sec (60 m) grid. Several distinct morpho-tectonic provinces are identified including: the deeply incised Malta–Hyblean Escarpment, numerous submarine canyons, broad regions of relatively flat seafloor dominated by fields of sediment waves, the gently undulating anticlinal fold-and-thrust belts of the external Calabrian accretionary wedge and the adjacent portion of the Western Mediterranean Ridge. The Calabrian arc can be divided into 4 domains (from SE to NW): 1) the undeformed Ionian abyssal plain, 2) the external evaporitic wedge, 3) the internal clastic wedge, 4) the Calabrian backstop (Variscan crystalline basement). The Calabrian accretionary wedge can also be divided laterally into two major lobes, the NE- and the SW lobes, and two minor lobes. The kinematics of the limit between the two major lobes is investigated and shown to be sinistral in the external (evaporitic) wedge. A network of radial slip lines within the southernmost external wedge unequivocally demonstrate ongoing dextral displacement of a rigid indenter (representing the corner of the clastic wedge) into the evaporitic wedge thereby confirming the geodynamic model of an active lateral slab tear fault here off eastern Sicily. The slab tear produces a series of major sub-parallel dextral strike-slip faults offshore Mt. Etna and south of the Straits of Messina consistent with the relative motions between Calabria and the Peloritan domain (NE Sicily). Abundant strike-slip faulting, and wide-spread folding and thrusting observed throughout the entire accretionary wedge, indicate regional shortening between the Ionian abyssal plain (foreland) and the Calabrian–Peloritan backstop caused by active subduction.
(Earth and Planetary Science Letters. vol. 461, n° 0012-821X, pp. 61 - 72, 02/01/2017)
LDO, INSU - CNRS, UBO EPE, CNRS, GEOMAR, CAU, MARUM, SHOM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GM, IFREMER, INSU - CNRS, UM, CNRS, UA, CNR, GEOAZUR 7329, INSU - CNRS, UniCA, CNRS, IRD [Occitanie], IRD, UniCA, ICREA, UTM
Fate of antibiotics from hospital and domestic sources in a sewage network
(Science of the Total Environment. vol. 575, n° 0048-9697, pp. 758-766, 01/01/2017)
METIS, EPHE, PSL, INSU - CNRS, SU, CNRS, HCMUT, VNU-HCM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A high-resolution temporal record of environmental changes in the Eastern Caribbean (Guadeloupe) from 40 to 10 ka BP
In neotropical regions, fossil bat guano accumulated over time as laminated layers in caves, hence providing a high-resolution temporal record of terrestrial environmental changes. Additionally, cave settings have the property to preserve such organic sediments from processes triggered by winds (deflation, abrasion and sandblasting) and intense rainfall (leaching away). This study reports both stable carbon and nitrogen isotope compositions of frugivorous bat guano deposited in a well-preserved stratigraphic succession of Blanchard Cave on Marie-Galante, Guadeloupe. These isotopic data are discussed with regard to climate changes and its specific impact on Eastern Caribbean vegetation during the Late Pleistocene from 40 to 10 ka cal. BP. Guano d 13 C values are higher than modern ones, suggesting noticeable vegetation changes. This provides also evidence for overall drier environmental conditions during the Pleistocene compared to today. Meanwhile, within this generally drier climate, shifts between wetter and drier conditions can be observed. Large temporal amplitudes in both d 13 C and d 15 N variations reaching up to 5.9‰ and 16.8‰, respectively, also indicate these oceanic tropical environments have been highly sensitive to regional or global climatic forcing. Stable isotope compositions of bat guano deposited from 40 to 35 ka BP, the Last Glacial Maximum and the Younger-Dryas reveal relatively wet environmental conditions whereas, at least from the end of the Heinrich event 1 and the Bølling period the region experienced drier environmental conditions. Nevertheless, when considering uncertainties in the model age, the isotopic record of Blanchard Cave show relatively similar variations with known proxy records from the northern South America and Central America, suggesting thus that the Blanchard Cave record is a robust proxy of past ITCZ migration. Teleconnections through global atmospheric pattern suggest that islands of the eastern Caribbean Basin could be also under the influence of a bipolar temperature gradients that impact the mean location of the ITCZ, with a Southern Hemisphere imprint during the glacial period and a more significant role of Northern Hemisphere during the last deglaciation.
(Quaternary Science Reviews. vol. 155, n° 0277-3791, pp. 198-212, 01/01/2017)
PACEA, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PEPS, UCBL, INSU - CNRS, CNRS
Inputs, dynamics and potential impacts of silver (Ag) from urban wastewater to a highly turbid estuary (SW France)
Although silver (Ag) has been listed as a priority pollutant for the aquatic environment by the European Union (Directive 2006/11/EC), the use of Ag-based products with antimicrobial effects is increasing in Europe, as well as North America and Asia. This study investigates personal care products (PCP) as a potential source of Ag in wastewater, as well as the dynamics and fate of Ag in the influent and effluent of a major urban wastewater treatment plant (WWTP) located on the fluvial part of the Gironde Estuary. Typical household PCPs marked as using Ag contained concentrations of up to 0.4 mg kg−1 making them likely contributors to urban Ag released into the aquatic environment. Silver concentrations in influent wastewater generally occurred during mid-week working hours and decreased during the night and on weekends clearly indicating the dominance of urban sources. Up to 90% of the total Ag in wastewater was bound to particles and efficiently (>80%) removed by the treatment process, whereas 20% of Ag was released into the fluvial estuary. Silver concentrations in wastewater effluents clearly exceeded estuarine concentrations and may strongly amplify the local Ag concentrations and fluxes, especially during summer rainstorms in low river discharge conditions. Further work should focus on environmental effects and fate of urban Ag release due to immediate localized outfall and/or the adsorption on estuarine particles and subsequent release as dissolved Ag chloro-complexes within the estuarine salinity gradient
(Chemosphere. vol. 167, n° 0045-6535, pp. 501-511, 01/01/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Spatial patterns in the condition index of the wild Pacific oyster Crassostrea gigas in a macrotidal coastal ecosystem: Influence of tidal processes and beyond
In macrotidal coastal ecosystems, spatial heterogeneity of the water column properties is induced by both oceanic and continental influences. Hydrodynamic processes generate a land-sea gradient of environmental conditions, affecting the biological performances of sedentary organisms. The aim of the present study is to establish an extensive spatial assessment in the reproductive investment of the wild Pacific oyster Crassostrea gigas in Arcachon Bay. This is done by looking for a relationship between the Lawrence and Scott condition index (LSCI) and two tidal processes: the immersion level (IL) and the local oceanic flushing time (LoFt). The LSCI of C. gigas was assessed, just before gamete release, at 68 sampling stations in Arcachon Bay. Oyster performance was overall low and spatially variable. Significant differences in the LSCI were detected between the outer and inner bay. Oyster reefs located toward the mouth of the bay exhibited high LSCI (between 9 and 11), while oyster reefs located in inner bay, especially in south-eastern part around the Eyre River, had low LSCI (below 6). Linear modelling allowed to highlight significant effects of both tidal processes IL and LoFt on the obtained LSCI gradient. IL, LoFt explained 33% of the spatial variability observed on LSCI (IL = 3%; LoFt = 17%; LoFt + IL: 13%), 6% were attributed to the intra-station variation (ISv). Thus, high IL and rapid LoFt favor a better development of somatic-gonadal volume, probably because of longer feeding time and higher supply of food from the ocean by tide flows. Disentangling the effects of IL and LoFt on LSCI allowed to describe the spatial pattern in 61% of variability not explained by both tidal factors. A residual gradient directed southeast-northwest highlighted that others factors, independent from IL and LoFt seems to hamper inner bay oyster reproductive performance. Consequently, investigating on the ecological functioning (Eyre influences), trophic potential and anthropogenic pressures of this zone seem crucial on the understanding of C. gigas reproductive pattern in Arcachon Bay.
(Journal of Sea Research (JSR). vol. 119, n° 1385-1101, pp. 28-36, 01/01/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, IFREMER
Satellite radar altimetry water elevations performance over a 200 m wide river: Evaluation over the Garonne River
For at least 20 years, nadir altimetry satellite missions have been successfully used to first monitorthe surface elevation of oceans and,shortly after, oflargeriversand lakes . For the last 5-10years, few studies have demonstrated the possibility toalsoobserve smaller water bodies than previously thought feasible (river smaller than 500m wide and lake below 10 km2). The present study aims at quantifyingthe nadir altimetry performance over a medium river (200m or lower wide) with a pluvio-nivalregime in a temperate climate (the Garonne River, France). Three altimetry missions have been considered : ENVISAT (from 2002 to 2010), Jason-2 (from 2008 to 2014) and SARAL (from 2013 to 2014).
(Advances in Space Research. vol. 59, n° 0273-1177, pp. 128-146, 01/01/2017)
LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNES
Combined effects of temperature and copper and S-metolachlor on embryo-larval development of the Pacific oyster, Crassostrea gigas
This study evaluates the combined effects of two contaminants (copper and a herbicide S-metolachlor) and temperature on the early life stages of the Pacific oyster Crasssotrea gigas,which is native to Arcachon Bay (southwest France). The responses of D-larvae, obtained fromwild and cultivated oysters,were investigated for one year during the oyster breeding period at different sampling sites and compared with the response of D-larvae from a commercial hatchery. Embryotoxicity was measured by considering the percentage of abnormal D-shaped larvae. Normal development of embryos occurred only from 22 °C to 26 °C. There were synergistic effects of copper at low and high temperatures. Native oysters appear particularly sensitive to an increase in water temperature, suggesting a future increase in the percentage of larval abnormalities as a result of global climate change. Hatchery oysters represent a good alternative model for studying the effects of both pollutants and climate change stressors.
(Marine Pollution Bulletin. vol. 115, n° 0025-326X, pp. 201-210, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, IRSTEA
New records of benthic amphipods, Jassa slatteryi Conlan, 1990 and Ampithoe valida Smith, 1873 (Crustacea: Peracarida: Amphipoda) for the Bay of Biscay, France, with morphological notes
Jassa slatteryi and Ampithoe valida were collected in the Bay of Biscay. Jassa slatteryi, a cosmopolitan species, was signalized before in European waters, in the Mediterranean Sea and in Brittany. Specimens collected in Arcachon Bay represent the second signalization on the European Atlantic coast. Ampithoe valida, a non-native species originally described in North America, was signalised in European waters before, in the Mediterranean Sea, Portugal and the Netherlands. Its presence in Arcachon Bay and Hossegor Lake is a first record on the French Atlantic coast for this species.
(Cahiers de Biologie Marine, n° 0007-9723, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Influence of Environmental Factors on the Fate of Legacy and Emerging Per- and Polyfluoroalkyl Substances along the Salinity/Turbidity Gradient of a Macrotidal Estuary
This study aimed at bridging knowledge gaps regarding the land-sea transport of per- and polyfluoroalkyl substances (PFASs) through riverine discharge into coastal waters. The present survey was conducted in the Gironde estuary (southwestern France) where PFASs were ubiquitously detected albeit at low levels. Emerging PFASs such as fluorotelomer sulfonates or polyfluoroalkyl phosphate diesters accounted for a relatively minor proportion of ∑PFASs, while perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorohexanoate were the predominant congeners. Multiple linear regressions provided insights into the relative influence of factors controlling PFAS sediment levels. In that respect, the organic carbon fraction (strongly correlated to sediment grain size) appeared as a more important controlling factor than black carbon or distance from upstream sources for long-chain perfluoroalkyl acids. In the maximum turbidity zone (suspended solids up to 2600 mg L–1), the particle-associated fraction was almost consistently >50% for long-chain perfluoroalkyl carboxylates and sulfonates (≥C8 and ≥ C6, respectively). Empirical models of KD partitioning coefficients were derived by integrating, for the first time, both particle-concentration and salting-out effects. These results represent significant progress toward the development of numerical transport models integrating both PFAS partitioning and 3D-hydrosedimentary dynamics, with a view to estimate PFAS mass budgets at the land-sea interface.
(Environmental Science and Technology. vol. 51, n° 0013-936X, pp. 12347-12357, 21/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPTC, UB, CNRS
First observations of the behaviour of the deep-sea amphipod Dulichiopsis dianae sp. nov. (Senticaudata, Dulichiidae) in the TAG hydrothermal vent field (Mid-Atlantic Ridge)
A “tiny and mysterious creature swinging on a stem”: that was the first observation of the new species Dulichiopsis dianae sp. nov. made during the remotely operated vehicle (ROV) dive devoted to the exploration of the surroundings of the vent site TAG (BICOSE cruise, 3550–3650 m). The viewing and analysis of the high-definition pictures from several dives (PL570, PL573 and PL575) corresponding to five different locations around TAG revealed that these organisms were amphipods, hung on erected and flexible masts (5–7 cm length) attached to the underlying hard substratum. Two specimens were opportunely sampled during dive PL575 (3637 m) with the suction sampler of the ROV and were identified as a new species ascribed to the genus Dulichiopsis (family Dulichiidae). The present study provides the morphological description of this new species, coupled with in situ observations of its behaviour and lifestyle in the vicinity of the TAG vent field. Taxonomic and ecological aspects of the family Dulichiidae are proposed here, as well as a review of the amphipod diversity in hydrothermal environments.
(Marine Biodiversity, n° 1867-1616, 21/06/2026)
ISYEB, MNHN, UPMC, EPHE, PSL, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS