Foredune morphological changes and beach recovery from the extreme 2013/2014 winter at a high-energy sandy coast
The beach-dune response at Truc Vert, SW France, is analysed using DGPS topographic surveys sampled every 2–4 weeks covering an alongshore distance of 1.5 km, combined with wave, tide and extreme water level hindcast and beach/dune photographs. During the 2013/2014 winter, which was the most energetic since at least 1948, the beach-dune system at Truc Vert eroded by approximately 180 m3 per beach width divided equally between beach and dune erosion. Beach and dune erosion was strongly variable alongshore, with cuspate-type rhythmic dune erosion scarps stripped of vegetation with a cross-shore amplitude of 25 m. The alongshore-variable scarps were coupled with an alongshore variability in elevation of the beach, with lower beach levels co-located with the megacusp bays. The following 10 months showed modest morphological beach and dune changes with, for instance, destabilisation of the scarped dune by trough blowouts, scarp slumping and filling and seasonal beach berm dynamics. The most profound morphological and vegetation changes occurred during the subsequent 10 months. Only 1.5 years after that winter, the beach-dune system at Truc Vert almost recovered to its pre-winter volume, but not to its pre-winter foredune profile. Most of the sand volume recovery occurred during spring-summer-autumn 2015 when approximately 120 m3/m of sand naturally came back in the system. The beach volume recovery rate was relatively steady and uncorrelated with wave conditions, with rates twice as large across the megacusp bay profile as across the that of the megacusp horns. During that period, the widened and risen dry beach provided large fetch length enhancing onshore windblown transport and a rapid rising of the backshore. The slumped and filled dune scarp, which was providing a high barrier to aeolian transport from the beach to the dune since the 2013/2014 winter, reformed as a dune ramp providing efficient conduit for beach-dune delivery/exchange of sediment by the end of the study. This process favoured both natural revegetation into the scarp and incipient foredune formation. Despite the reinstatement of natural processes between the beach and the dune, the dune foot was still located landward by more than 10 m on average with respect to its pre-2013/2014 winter position. This study shows that even after the most severe winter over the last 68 years in terms of average wave energy arriving at the coast, beach recovery can be a relatively fast process along high-energy sandy beaches backed by large dunes. In contrast foredune recovery, which timing and magnitude can provide a proxy measure for the resilience of the system to climatic variability and change, is a much slower process that can take years to decades.
(Marine Geology. vol. 385, n° 0025-3227, pp. 41-55, 01/03/2017)
CNRS, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OASU, UB, INSU - CNRS, ULR, CNRS, INRAE, LETG - Brest, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN
Chaetozone corona (Polychaeta, Cirratulidae) in the Bay of Biscay: a new alien species for the North-east Atlantic waters?
The cirratulid species Chaetozone corona is reported for the first time from the North-east Atlantic waters. Several specimens were collected during oceanographic surveys between 1996 and 2015 from soft bottom habitats along the coasts of Brittany (Western France). This species, originally described from the coast of California, was recently recorded for the first time from the Mediterranean Sea. We hypothesize that this species could have been recently introduced to the Atlantic coasts of Europe and colonized the northern coast of Bay of Biscay from the Loire estuary to the Iroise Sea. We discuss the potential vectors of introduction and the main environmental factors that could explain its current distribution. An identification key to all the known North-east Atlantic species of Chaetozone is given.
(Journal of the Marine Biological Association of the United Kingdom. vol. 97, n° 0025-3154, pp. 433-445, 01/03/2017)
IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEP, EEP, IFREMER
Development of a multi-residue method for scrutinizing psychotropic compounds in natural waters
The present work describes a multi-residue SPE-UPLC–MS/MS method aiming at the characterization of 68 compounds in natural waters, including parent compounds as well as their major metabolites and glucuronide conjugates. Development was conducted toward the quantitative determination of a broad range of analytes belonging to different class of psychotropic drugs such as benzodiazepines, antidepressants, stimulants, opiates and opioids, anticonvulsants, anti-dementia drugs, analgesic and anti-inflammatory drugs (as anthropic indicators) in the low ng L−1 range of concentration. Satisfactory extraction recoveries >70% were obtained for the majority of analytes (49 out of 68) allowing low limits of quantification. LOQ ranged between 0.1 and 17.8 ng L−1 and were lower than 5 ng L−1 for 94% of investigated analytes. Furthermore, addition of 25 isotopic labeled standards allowed to ensure reliability of the optimized method. Quantification errors were typically below 15% with relative standard variations <10% in intermediate precision conditions. Finally, the developed method was implemented in natural waters; sampling campaigns were conducted in the Seine River as a demonstration of the applicability and adequation of the method for its purpose. As a result, 48 out of 68 analytes were identified or quantified; some of them like memantine, rivastigmine, zolpidem 4-phenyl-carboxylic acid, zolpidem 6-carboxylic acid for one of the first time in surface waters. Among investigated psychotropic compounds and metabolites, tramadol, codeine, oxazepam, venlafaxine, O-desmethylvenlafaxine, gabapentin, carbamazepine and 10,11-dihydro-10,11-dihydroxycarbamazepine were found to be the most abundant.
(Journal of Chromatography B Biomedical Sciences and Applications. vol. 1047, n° 0378-4347, pp. 160-172, 01/03/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Epigenetic, histopathological and transcriptomic effects following exposure to depleted uranium in adult zebrafish and their progeny
(Aquatic Toxicology. vol. 184, n° 0166-445X, pp. 14-25, 01/03/2017)
IRSN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CIBEST, SYMMES, INC-CNRS, CNRS, UGA [2016-2019], IRIG, DRF (CEA), KIT, C3R, IRSN, CNRS
Toxicity effects of an environmental realistic herbicide mixture on the seagrass Zostera noltei
Worldwide seagrass declines have been observed due to multiple stressors. One of them is the mixture of pesticides used in intensive agriculture and boat antifouling paints in coastal areas. Effects of mixture toxicity are complex and poorly understood. However, consideration of mixture toxicity is more realistic and ecologically relevant for environmental risk assessment (ERA). The first aim of this study was to determine short-term effects of realistic herbicide mixture exposure on physiological endpoints of Zostera noltei. The second aim was to assess the environmental risks of this mixture, by comparing the results to previously published data. Z. noltei was exposed to a mixture of four herbicides: atrazine, diuron, irgarol and S-metolachlor, simulating the composition of typical cocktail of contaminants in the Arcachon bay (Atlantic coast, France). Three stress biomarkers were measured: enzymatic activity of glutathione reductase, effective quantum yield (EQY) and photosynthetic pigment composition after 6, 24 and 96 h. Short term exposure to realistic herbicide mixtures affected EQY, with almost 100% inhibition for the two highest concentrations, and photosynthetic pigments. Effect on pigment composition was detected after 6 h with a no observed effect concentration (NOEC) of 1 μg/L total mixture concentration. The lowest EQY effect concentration at 10% (EC10) (2 μg/L) and pigment composition NOEC with an assessment factor of 10 were above the maximal field concentrations along the French Atlantic coast, suggesting that there are no potential short term adverse effects of this particular mixture on Z. noltei. However, chronic effects on photosynthesis may lead to reduced energy reserves, which could thus lead to effects at whole plant and population level. Understanding the consequences of chemical mixtures could help to improve ERA and enhance management strategies to prevent further declines of seagrass meadows worldwide.
(Environmental Pollution. vol. 222, n° 0269-7491, pp. 393-403, 01/03/2017)
LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LERAR, COAST, IFREMER
Photodegradation of sulfamethazine, sulfamethoxypiridazine, amitriptyline, and clomipramine drugs in aqueous media
The photochemical transformation of two antibacterial sulfonamides, namely sulfamethazine (SMT) and sulfamethoxypyridazine (SMP), and two tricyclic antidepressants, namely amitriptyline (AMT) and clomipramine (CMP) were investigated. Experiments conducted in river water under artificial sunlight irradiation show an acceleration of the degradation for SMT, SMP, and CMP of a factor 1.6–7.7 by comparison to purified water. This acceleration is, at least partially, due to photosensitized reactions which can occur in river water. The photodegradation of CMP was particularly fast. In addition, no degradation was observed for AMT in purified water while photosensitized reaction occurs. Under ultra-violet (254 nm) irradiation in purified water, the four drugs were degraded. Calculated quantum yields of photodegradation were of 4.3 × 10−3, 5.1 × 10−3, 7.6 × 10−3, and 65.0 × 10−3 respectively for SMT, SMP, AMT, and CMP. UV coupled with hydrogen peroxide (UV/H2O2) was used as an advanced oxidation process for water depollution. The calculated second order rate constants of reaction with hydroxyl radicals were of 5.0 × 109, 5.0 × 109, 8.0 × 109 and 9.5 × 109 L mol−1 s−1 for SMT, SMP, AMT and CMP, respectively. Finally, the structures of photoproducts were proposed according to LC–MS/MS analyses. The elimination of SO2 was the main photochemical process for SMT and SMP. In the case of AMT and CMP, hydration and hydroxylation, respectively, were observed.
(Journal of Photochemistry and Photobiology A: Chemistry. vol. 336, n° 1010-6030, pp. 176-182, 01/03/2017)
LAEC-CNRS, CNRS-L, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Oxidation of danofloxacin by free chlorine—kinetic study, structural identification of by-products by LC–MS/MS and potential toxicity of by-products using in silico test
In this study, we aimed to investigate the kinetics and the mechanism of reaction of the fluoroquinolone antibacterial danofloxacin (DANO) by free available chlorine (FAC) during water chlorination process. Kinetic study was thus performed at pH 7.2, 20 °C in the presence of an excess of total chlorine. Under these experimental conditions, a second-order reaction rate constant (first-order relative to DANO concentration and first-order relative to FAC concentration) was evaluated to k~1446 M-1 s-1. Five degradation products were identified at different reaction times. Their structures were investigated by using fragmentations obtained at different CID collision energies in MS/MS experiments. Moreover, the toxicity of the proposed structures was predicted by using T.E.S.T.
(Environmental Science and Pollution Research. vol. 24, n° 0944-1344, pp. 7982-7993, 01/03/2017)
LAEC-CNRS, CNRS-L, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS-L
Diatom response to oceanographic and climatic changes in the Congo fan area, equatorial Atlantic Ocean, during the last 190ka BP
Changes in siliceous productivity in the eastern Equatorial Atlantic Ocean, off the Western African margin, over the last several glacial cycles have been either related to global-to-regional oceanographic changes (upwelling intensity) or climate changes (precipitation and river discharge). Based on diatom assemblages in core KZAI-02, located to the south of the mouth of the Congo River, integrated with a selection of geochemical proxies, we show that siliceous productivity in the southeastern Angola Basin responded to non-linear interactions between both oceanographic and climate changes over the last 190,000 years. High diatom accumulation rates were recorded in the middle part of MIS 6, in cold substage MIS 5d and in MIS 3-2. During these intervals, high diatom productivity was sustained essentially by nutrients, including dissolved silica, injected by the Congo River into the ocean. The highest productivity was observed during MIS 3, when nutrients were sourced both from the river and regional upwelling. Low diatom accumulation rates were recorded during early and late MIS 6, MIS 5e, early MIS 4 and during the Holocene. These resulted either from low river discharge and overall low nutrient stocks in the Angola Basin (despite evidence for upwelling) or from extremely high river discharge. In the case of the latter, the terrigenous load drastically increased the turbidity of the surface waters in the southeastern Angola Basin and lowered phytoplankton productivity despite the presence of sufficient dissolved silica
(Palaeogeography, Palaeoclimatology, Palaeoecology. vol. 469, n° 0031-0182, pp. 47 - 59, 01/03/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LGO, UBS, IFREMER, UBO EPE, CNRS, LDO, INSU - CNRS, UBO EPE, CNRS, IFREMER
Integrated monitoring of chemicals and their effects on four sentinel species, Limanda limanda, Platichthys flesus, Nucella lapillus and Mytilus sp., in Seine Bay: A key step towards applying biological effects to monitoring
The International workshop on Integrated Assessment of CONtaminants impacts on the North sea (ICON) provided a framework to validate the application of chemical and biological assessment thresholds (BACs and EACs) in the Seine Bay in France. Bioassays (oyster larval anomalies, Corophium arenarium toxicity assay and DR Calux) for sediment and biomarkers: ethoxyresorufin-O-deethylase (EROD) activity, acetylcholinesterase (AChE) activity, lysosomal membrane stability (LMS), DNA strand breaks using the Comet assay, DNA adducts, micronucleus (MN), PAH metabolites, imposex, intersex and fish external pathologies were analysed in four marine sentinel species (Platichthys flesus, Limanda limanda, Mytilus sp. and Nucella lapilus). Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals were analysed in biota and sediment. Results for sediment and four species in 2008–2009 made it possible to quantify the impact of contaminants using thresholds (Environmental Assessment Criteria/EAC2008: 70% and EAC2009: 60%) and effects (EAC2008: 50% and EAC2009: 40%) in the Seine estuary. The Seine estuary is ranked among Europe's most highly polluted sites.
(Marine Environmental Research. vol. 124, n° 0141-1136, pp. 92-105, 01/03/2017)
IFREMER, MSS, IEO | CSIC, CSIC, ABTE, UNICAEN, NU, UNIROUEN, NU, LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMA, ULH, NU, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, BSH, UiO
Saving Our Marine Archives
(Eos, Transactions American Geophysical Union. vol. 98, n° 0096-3941, 24/02/2017)
BTP, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, LDEO, ANU, LOCEAN, IPSL, ENS-PSL, PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, IP Paris, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, USC, RSES, ANU, PARVATI, LOCEAN, IPSL, ENS-PSL, UVSQ, UPMC, CEA, INSU - CNRS, X, CNES, CNRS, MNHN, IRD, UPMC, INSU - CNRS, CNRS, UON, AWI, ISU