Impact of hypoxia on hemolymph contamination by uranium in an aquatic animal, the freshwater clam Corbicula fluminea
Multi-stress situations are a major question and low-oxygenated waters (hypoxia) are a growing problem. Importantly, hypoxia stimulates the ventilatory flow rate in aquatic animals and this increases gill exposure to contaminants. Surprisingly, in the freshwater clam Corbicula fluminea, this is associated with increased bioaccumulation of uranium in gills but not in deep tissues. We searched for an explanation by analyzing hemolymph U-transport in Corbicula exposed to 0.36 μM dissolved uranium at various O2-levels for 10 days. In hypoxia, one observed an increased U concentration in the arterial hemolymph flowing from gills to tissues but this was not associated with an increased U concentration in the venous hemolymph nor in the other tissues. We conclude that the cardiac flow rate must have decreased to explain this absence of over-accumulation. In addition to its already known deleterious effects, uranium can thus deeply impair cardiac flow rate in exposed aquatic animals during multi-stress exposures. © 2008 Elsevier Ltd. All rights reserved.
(Environmental Pollution. vol. 156, n° 0269-7491, pp. 821-826, 01/12/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSN/DEI/SECRE/LRE, IRSN/DEI/SECRE, IRSN
Live foraminifera from the open slope between Grand Rhône and Petit Rhône Canyons (Gulf of Lions, NW Mediterranean)
(Deep Sea Research Part I: Oceanographic Research Papers. vol. 55, n° 0967-0637, pp. 1532-1553, 01/11/2008)
UA, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, OCEANIS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CEFREM, UPVD, INSU - CNRS, CNRS, HCL, HCL, HIFIH, UA
Ocean color measurements onboard a jet-ski: consistency for calval exercise of high-resolution satellite imagery?
An original data set has been acquired on the 5th of April 2008 during the international field experiment ECORS-Truc Vert 2008 (SW France) in the nearshore zone over a complex bathymetry and in moderate turbid waters (SPM <10 mg/l). This data set synchronizes in-situ reflectance measurements onboard a jet-ski, bathymetric surveys and a Formosat-2 high-resolution satellite acquisition. The jet-ski provides an interesting mean to gather optical data in shallow waters and in environments hard to sample with traditional coastal ships. An experimental device has been implemented on the jet-ski, equipped with two TRIOS RAMSES sensors which measure simultaneous atmospheric downwelling irradiances Ed and in-water upwelling radiances Lu in the 350-950nm range. Water samples have also been collected at different stages of the jet-ski trajectory (3-25m water depth) in order to assess the concentrations of the ocean constituents (SPM and Chl-a). In the current study we present a methodology to validate FORMOSAT-2 high-resolution ocean color data using “jetski” reflectance measurements, which first require a detailed analysis. The reflectance spectra measurements are shown to be consistent : (i) they are typical of the presence of mineral particles with light absorption at short wavelengths ; (ii) their shape and magnitude depend on the depth and the water type (turbidity) ; (iii) some of them, especially in low turbid waters, are similar to other reflectance spectra measured northward from a ship (Gironde mouth). Thus, the use of “jet-ski” ocean color measurements appears to be adequate for remote sensing calval activities in shallow case-2 waters.
(pp. 10 p, 01/11/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The Virtual Fields Method for Extracting Constitutive Parameters From Full‐Field Measurements: a Review
ABSTRACT: The virtual fields method has been developed for extracting constitutive parameters from full‐field measurements provided by optical non‐contact techniques for instance. It is based on the principle of virtual work written with some particular virtual fields. This paper can be regarded as a general review summarising some 15 years of developments of this method. The main aspects of the method are first recalled in the case of both linear and non‐linear constitutive equations. They are then illustrated by some recent relevant examples. Some studies underway as well as relevant issues to be addressed in the near future are eventually discussed.
(Strain. vol. 42, n° 0039-2103, pp. 233-253, 29/10/2008)
IUT d'Allier, UBP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, TECH ECO (ex-ITESE), CEA-DES (ex-DEN), CEA, IP, CNRS, UCA, INP Clermont Auvergne, UCA, IP, UBP, SIGMA Clermont, CNRS
Cartographie des faciès bio-sédimentaires du Bassin d'Arcachon à partir de l'imagerie FORMOSAT-2
(pp. 10 p, 01/10/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, LERAR, COAST, IFREMER
In-water reflectance spectra measured on-board a jet-ski across a complex nearshore zone of case-2 waters during the ECORS experiment
In situ reflectance spectra have been measured during the international field experiment ECORS-Truc Vert 2008 (SW France) in the nearshore zone over a complex bathymetry and in moderately turbid waters (SPM <10 mg/l). Measurements of the atmospheric downwelling irradiance (Ed) and in-water upwelling radiance (Lu) were realized on board a jet-ski with TRIOS RAMSES sensors together with water samples to assess the optically significant seawater constituents (SPM, CDOM, Chl-a). Marine reflectance spectra were collected under low-energy swell conditions (Hs=0.5 m) in water depths of 3-25 m and after a long period of very energetic swells (Hs > 7 m). The jet-ski provides a valuable mean to gather optical data in shallow waters and in environments hard to sample with traditional coastal ships. Main results show reflectance spectra are typical of the presence of mineral particles with light absorption at short wavelengths. The shape and magnitude of the spectra are also very representative of the type of waters and bottom depth : the maximum of reflectance is reached around 500 nm in low turbidity waters (SPM<1 mg/l) while moving to the yellow spectral band (570-580 nm) in moderately turbid shallow waters (SPM=4 mg/l) where rip currents drive sediments outside the surf zone. A very original dataset has been obtained considering the synchronization of optical data, bathymetric surveys and Formosat-2 high resolution satellite image all collected the same day (5 April 2008). In the present study, this dataset is tested to inverse optical models for bathymetry retrieval in order to compute diachronic bathymetric maps as the coastline is changing very fast and need frequent updates of the bathymetry.
(pp. 8 p, 01/10/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The impact of lateral carbon fluxes on the European carbon balance
To date, little has been written about the important role played by processes transporting carbon laterally over continents, and from continents to oceans. These processes have an impact on the CO2 budgets and on the carbon budgets at local, regional and continental scales. We estimated the impact on the European carbon balance of the transport of carbon by the trade of wood and food products, by the emission and oxidation of reactive reduced carbon species, and by rivers and freshwater systems up to estuaries. The analysis is completed by new estimates of the carbon fluxes of coastal seas. The magnitude of the CO2 and carbon fluxes caused by lateral transport over Europe is comparable to current estimates of carbon gain by European ecosystems. At the continental level, we estimate a CO2 sink over Europe of 140 TgC yr-1 and a carbon sink of 50 TgC yr-1 being caused by lateral transport processes.
(Biogeosciences. vol. 5, n° 1726-4170, pp. 1259-1271, 05/09/2008)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, ICOS-ATC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, SEOS, UVIC, MERMAID, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Interglacial variability (MIS 5 and MIS 7) and dinoflagellate cyst assemblages in the Bay of Biscay (North Atlantic)
The interglacial periods of the late Quaternary are frequently investigated as they constitute potential analogues for our modem climate and may shed light on the key questions of natural climate variability and future developments. The aim of this work is to reconstruct the paleoenvironmental history of Marine Isotope Stages (MIS) 5 and 7 in deep-sea sediments of the northern Bay of Biscay (North East Atlantic Ocean). On the basis of a multiproxy compilation, including analysis of dinoflagellate cyst assemblages, we discuss the nature of the paleoenvironmental and paleoclimate changes that took place in this region. Recurrent successions Of Species marking the beginning and the Termination of the Interglacial Complexes (MIS 5 and MIS 7) revealed a coherent scheme of water mass migration during these key transitional periods. Moreover, our data extend knowledge about the ecology of several dinoflagellate taxa. In particular, we discuss the ecology of Spiniferites septentrionalis and note that this species can be used as a biostratigraphical tracer in North Atlantic Quaternary sediments, until a major event of iceberg calving occurred during MIS 6. dated to around 150 ka BP. The dinocyst Spinferites mirabilis appears to be an important proxy for recognizing warm intervals within Interglacial Complexes. During MIS 5e, the Last Interglacial, this species is represented by the highest percentages ever recorded in sediments from the North Atlantic region. Peak occurrence of this species during MIS 7 indicates that substage MIS 7c, the second warm interval of the Penultimate Interglacial, represents the climatic optimum during the MIS 7 Interglacial Complex. (C) 2008 Elsevier B.V. All rights reserved.
(Marine Micropaleontology. vol. 68, n° 0377-8398, pp. 136-155, 01/07/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Use of Biotic Indices in semi-enclosed coastal ecosystems and transitional waters habitats - Implications for the implementation of the European Water Framework Directive
This study deals with the application of macrozoobenthos-based biotic indices (BI) within the frame of the implementation of the European Water Framework Directive. More precisely, this study aimed at assessing the performance of five recently developed methodologies (BI) for the assessment of ecological quality status (EcoQ) in two semi-enclosed, sheltered coastal ecosystems and in one transitional water body situated along the Western French coast, namely Marennes-Oléron Bay, Arcachon Bay, and the Seine Estuary. This study showed that these five indices rarely agreed with each other, describing very different pictures of the overall EcoQ of the three study sites. This work also clearly underlined the limitations of these approaches, notably the dependency of most of these BI and the resulting EcoQ classifications on habitat characteristics, more particularly to natural levels of sediment silt–clay content and the location of stations in the subtidal or the intertidal. The implication of our observations concerning the use of these BI for implementation of the WFD is discussed in terms of definition of habitat-specific reference conditions and necessity to adjust thresholds to the particular habitat occurring in semi-enclosed ecosystems. Meanwhile, the unmodified use of these BI severely impaired accurate assessment of EcoQ and decision-making on the managers’ point of view.
(Ecological Indicators, n° 1470-160X, pp. 360-372, 01/07/2008)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], GIP-Seine-Aval, LIENSs, INSU - CNRS, ULR, CNRS, CRELA, IFREMER, ULR, CNRS, IFREMER
In vitro study of the effects of cadmium on the activation of the estrogen response element using the YES screen
(Marine Environmental Research. vol. 66, n° 0141-1136, pp. 108, 11/06/2008)
ULH, NU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS