Slope-to-basin stratigraphic evolution of the carbonate northwestern Great Bahama Bank (Bahamas) during the Neogene to Quaternary: interactions between downslope and bottom currents deposits
Multichannel high-resolution seismic data along the northwestern margin of the Great Bahama Bank (GBB), Bahamas, details the internal geometry and depositional history of a Neogene-Quaternary carbonate slope-to-basin area. The stratigraphic architecture through this period evolves from (i) a mud-dominated slope-apron during the Miocene, (ii) a debris-dominated base-of-slope apron during the Late Pliocene, and then (iii) return to a slope-apron with very short prograding clinoformal aprons during the Pleistocene. This geometric evolution was broadly constrained by the development of the Santaren Drift by bottom current since the Langhian. The drift expands along the northwestern GBB slope, forming a continuous correlative massive feature that shows successive phases of growth and retreat and influenced the downslope sediments distribution. Indeed, Late Pliocene deposits are confined into the moat, forming a strike-continuous coarse debrites belt along the mid-slope, preventing their free expansion into the basin. The occurrence of basinal drift that operated since 15 Ma showed a significant upslope growth around 3.6 Ma and is interpreted as resulting from the closure of the Central American Seaway (CAS) which also coincides with a global oceanographic re-organization and climate changes in the Northern Hemisphere.
(Basin Research. vol. 29, n° 0950-091X, pp. 699-724, 01/12/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GR, UR, INSU - CNRS, CNRS, [Total Energies. Anciennement : Total, TotalFina, TotalFinaElf]
Regional and latitudinal patterns of soft-bottom macrobenthic invertebrates along French coasts: Results from the RESOMAR database
This study aims to describe the patterns of soft bottom macrozoobenthic richness along French coasts. It is based on a collaborative database developed by the “Réseau des Stations et Observatoires Marins” (RESOMAR). We investigated patterns of species richness in sublittoral soft bottom habitats (EUNIS level 3) at two different spatial scales: 1) seaboards: English Channel, Bay of Biscay and Mediterranean Sea and 2) 0.5° latitudinal and longitudinal grid. Total observed richness, rarefaction curves and three incidence-based richness estimators (Chao2, ICE and Jacknife1) were used to compare soft bottom habitats species richness in each seaboard. Overall, the Mediterranean Sea has the highest richness and despite higher sampling effort, the English Channel hosts the lowest number of species. The distribution of species occurrence within and between seaboards was assessed for each major phylum using constrained rarefaction curves. The Mediterranean Sea hosts the highest number of exclusive species. In pairwise comparisons, it also shares a lower proportion of taxa with the Bay of Biscay (34.1%) or the English Channel (27.6%) than that shared between these two seaboards (49.7%). Latitudinal species richness patterns along the Atlantic and English Channel coasts were investigated for each major phylum using partial LOESS regression controlling for sampling effort. This showed the existence of a bell-shaped latitudinal pattern, highlighting Brittany as a hotspot for macrobenthic richness at the confluence of two biogeographic provinces.
(Journal of Sea Research (JSR). vol. 130, n° 1385-1101, pp. 96-106, 01/12/2017)
INTECHMER, Cnam, LUSAC, UNICAEN, NU, LEMAR, IRD, IFREMER, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, LECOB, SU, CNRS, OOB, SU, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, LERBN, COAST, IFREMER, IFREMER, AD2M, SU, CNRS, SBR, SU, CNRS, SBR, SU, CNRS, FR2424, SBR, SU, CNRS, CRESCO, MNHN, IFREMER, LIENSs, INSU - CNRS, ULR, CNRS, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, DGD.REVE, MNHN
Dielectric Losses of Paper in the THz Domain: Literature Review, Needs for Future Research, and Prospective Solutions
(Physica Status Solidi A (applications and materials science). vol. 214, n° 1862-6300, pp. 1700356, 01/12/2017)
TUHH, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IMEP-LAHC, Grenoble INP, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019], CTP
L’ingénierie écologique appliquée aux zones de rejet végétalisées : élimination de micropolluants, biodiversité et intégration socio-territoriale
(TSM. Techniques Sciences Méthodes – Génie urbain, génie rural. vol. 12, n° 0299-7258, 01/12/2017)
CITERES - UMR 7324, UT, CNRS, LyRE, EHESP, CHROME, UNIMES, LPTC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Study of the degradation process of ofloxacin with free chlorine by using ESI-LCMSMS: Kinetic study, by-products formation pathways and fragmentation mechanisms
This study was conducted to gain a better understanding of the fate of fluoroquinolone antibacterial ofloxacin (OFX) which is the free available chlorine (FAC) in order to determine its effect during water chlorination process. The Direct reactions of FAC with OFX were quite rapid. A half-life of 7.7 s was measured under pseudo-first order conditions in the presence of an excess of total chlorine ([FAC]0 = 13 μM and [OFX]0 = 0.55 μM at pH 7.2 and 20 °C in buffered reagent water. Free chlorine reactions rates were of first-order type in both substrate and oxidant with specific second-order rate constants of 6.8 × 103 M-1 s-1. No induced back reactions or other interference by using thiosulfate to stop the chlorination reaction was shown. The seven products of the reaction were determined by using the LC/MS/MS analysis. Structures were investigated due to the explication of transitions obtained at different CID energies by LC-ESI-MS/MS. Pathways of the formations of these by-products were presented in this study and pathways of the fragmentations of pseudo molecular ions of the structures proposed were presented in supplementary files.
(Chemosphere. vol. 189, n° 0045-6535, pp. 46-54, 01/12/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Occurrence survey and spatial distribution of perfluoroalkyl and polyfluoroalkyl surfactants in groundwater, surface water, and sediments from tropical environments
The occurrence and spatial distribution of 22 selected perfluoroalkyl and polyfluoroalkyl substances (PFASs) in surface water (n=75), groundwater (n=80) and surficial sediment (n=15) were investigated for the first time in the tropical areas constituted by the French Overseas Territories (French Guiana, Guadeloupe, Martinique, Mayotte and Reunion). Descriptive statistics and correlations between PFASs were evaluated through the use of specific statistical treatments to handle left-censored data ("non-detects"). PFASs were ubiquitous in these samples and detection frequencies as high as 79% for perfluorooctane sulfonate (PFOS) and 65% for perfluorooctanoate (PFOA) were reported in surface waters. Sigma PFASs was in the range (Science of the Total Environment. vol. 607, n° 0048-9697, pp. 243 - 252, 01/12/2017) EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INERIS, BRGM
Tentative reconstruction of the 1998–2012 hiatus in global temperature warming using the IPSL–CM5A–LR climate model
The period running from 1998 to 2012 has experienced a slower increase in global temperature at the surface of the Earth than the decades before. Several explanations have been proposed, ranging from internal variability of the climate system to a contribution of the natural external forcing. In this study, we use the IPSL-CM5A-LR climate model to test these different hypotheses. We consider historical simulations, including observed external forcing, in which nudging towards observed sea surface temperature has been applied to different regions of the ocean to phase the decadal variability of large-scale modes in the Atlantic and the Pacific to observations. We find that phasing the tropical Pacific is reducing the warming trend detected in historical simulations by a factor of two, but the remaining trend is still twice as large as the observed one. Combining the tropical Pacific phasing and the potential effect of recent eruptions allows us to fully reproduce the observed hiatus. Conversely, nudging the Atlantic does not drive any hiatus in this model.
(Comptes Rendus. Géoscience. vol. 349, n° 1631-0713, pp. 369 - 379, 01/12/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PARVATI, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS
Varve formation during the past three centuries in three large proglacial lakes in south-central Alaska
The sediments stored in the large, deep proglacial lakes of south-central Alaska are largely unstudied. We analyzed sediments in 20 cores, up to 160 cm long, from Eklutna, Kenai, and Skilak Lakes, using a combination of repeated lamination counting, radionuclide dating, event stratigraphy, and tephrochronology. We show that the characteristically rhythmic layers were deposited annually. Most of these glacial varves consist of one coarse-grained base and a fine-grained top, but varves composed of multiple coarse-grained turbidite pulses are common too. They are likely related to successive episodes of high sediment discharge during flooding, and they become more frequent in all three lakes, along with increased sedimentation rates, during the nineteenth century late phase of the Little Ice Age. These flood turbidites were generated by rain events and intense melting of snow and ice. Other (mega) turbidites are a result of earthquake-triggered slope collapses (e.g., A.D. 1964). Some event layers are present in all three lakes. In addition, the annual time series of varve thickness (normalized annual sedimentation rate) are significantly correlated among the three lakes (ρ > 0.27; p < 0.001). Differences between the varve thickness records can be attributed partly to the dam construction at Eklutna Lake and outbursts from an ice-dammed lake at Skilak Lake. Geomorphologic differences among the catchments result in further differences in sedimentation patterns in the three lakes.
(Geological Society of America Bulletin. vol. 130, n° 0016-7606, pp. 757-774, 22/11/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of three pesticides on Gomphonema gracile's fatty acids
Fatty acids are essential elements for the structure of biological membranes and for the storage of metabolic energy. They are used as a source of energy by metabolism at each trophic level, making fatty acids biochemically and physiologically important compounds (Neves et al. 2015). In the trophic chain, many fatty acids are only synthesized by microalgae and bacteria before being transferred via herbivorous invertebrates to fish and ultimately to humans (Arts et al. 2001). For example, highly unsaturated fatty acids (HUFA) such as eicosapentaenoic acid (EPA; C20:5n3), can not be synthesized de novo or in insufficient proportions by animals (Saito and Aono 2014). That is why fatty acid analysis is commonly used to study trophic interactions in food chains. Generally, microalgae with a high proportion of EPA, such as diatoms, are an excellent source of food for animals but the concentrations of these different fatty acids can vary according to the stage of growth of the organism and according to different environmental parameters including pesticide exposure (Brett et al. 2006, Robert et al. 2007, Burns et al. 2011, Filimonova et al. 2016). Moreover, for several years, the intensive use of pesticides caused many problems to the environment, making pesticides major pollutants of aquatic ecosystems (Aydinalp and Porca 2004). The aim of this study is to investigate the impact of 3 pesticides on diatom's fatty acids. To address this issue, a model freshwater diatom (Gomphonema gracile) was exposed to three herbicides, with three different cellular targets, at environmentally relevant and higher concentrations (diuron and S-metolachlor, C1= 1 µg/L and C2= 10 µg/L; glyphosate, C1= 5 µg/L and C2= 50 µg/L). After a 1-week exposure, fatty acid compositions of diatoms were determined by gas chromatography. In comparison with control samples the percentage of 1) polyunsaturated fatty acids (PUFA) decreased with S-metolachlor contamination (C2); 2) saturated fatty acid (SFA) and monounsaturated (MUFA) decreased with diuron and glyphosate exposure (C2). The decrease of PUFA is a direct impact and can be explained by the mode of action of S-metolachlor which inhibits elongases. Concerning diuron and glyphosate, the decrease of SFA and MUFA can reflect an indirect effect, which can be explained by the mode of action of these two pesticides which respectively blocks electron transfer in photosynthesis, and inhibits the synthesis of aromatic aminoacids.
(pp. 1, 21/11/2017)
UR EABX, IRSTEA, INRA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Évaluation in vitro et in vivo des perturbateurs endocriniens chez le poisson zèbre : cas de substances seules et en mélanges
L’objectif de ce travail de thèse est d’évaluer le potentiel de nouveaux bio-essais in vitro et in vivo basés sur le poisson zèbre pour la biosurveillance de la contamination chimique de l’eau par les xeno-estrogènes. Pour cela, les bio-essais ont été appliqués pour évaluer les effets de polluants aquatiques environnementaux seuls, mais aussi en mélanges simples (reconstitués) et complexes (échantillons environnementaux). L’évaluation d’échantillons d’eau à travers les bioessais in vitro humain (MELN) et poisson zèbre (ZELH-zfERβ2) a montré des différences qualitatives et quantitatives de réponse, non expliquées par les molécules estrogéniques détectées. Afin de mieux comprendre ces différences, l’activité de polluants aquatiques a été caractérisée sur les différents modèles, individuellement et au sein de mélanges de 2 à 12 polluants, combinant molécules estrogéniques et non estrogéniques pour simuler des situations environnementales.Les résultats obtenus montrent que les bio-essais basés sur le poisson zèbre répondent différemment, et parfois de manière opposée, au modèle humain MELN aux mélanges reconstitués. Ces différences s’expliquent par des sensibilités différentes à certaines molécules entrainant des interactions avec la réponse aux xeno-oestrogènes spécifiques à chaque modèle biologique. Dans son ensemble, ce travail montre que les particularités biologiques de chaque bioessai peuvent influencer la réponse des xeno-estrogènes quand présents au sein de mélange avec d’autres polluants. Ces résultats sont discutés au regard de l’utilisation de bio-essais dans l’évaluation de la contamination chimique des masses d’eau.
(21/11/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INERIS