Cadmium bioconcentration in the echinoid Paracentrotus lividus: Influence of the cadmium concentration in seawater     

Michel Warnau  Jean-Louis Teyssié  Scott W. Fowler 《Marine environmental research》1997,43(4):303-314

Uptake and loss kinetics of cadmium were studied in Paracentrotus lividus exposed for 24 d to different stable Cd concentrations (0 to 1.14 μg Cd l⁻¹) and ¹⁰⁹Cd tracer added to seawater. The whole-body uptake kinetics were linear over the time course of the experiment. The whole-body ¹⁰⁹Cd concentration factor was independent of the stable Cd concentration in ambient seawater. Bioconcentration of Cd in whole individuals and their body compartments was directly proportional to the Cd concentration added to the seawater. The echinoid digestive tract wall showed the highest degree of Cd uptake. Whole-body loss kinetics were described by a 2-component exponential equation. The loss kinetics were similar for each of the treatments examined. Cadmium was found to display a long biological half-life in echinoid tissues; the major fraction (73 to 85%) of the Cd taken up by echinoids was eliminated following a loss component whose biological half-life was of the order of 1 year, regardless of the absolute Cd concentration accumulated by the echinoid. Paracentrotus lividus is suggested as a valuable biomonitor of Cd, particularly where knowledge of Cd concentration variations over long-term is of interest.  相似文献   

An adaptive, integrated "acoustic-trawl" survey design for Atlantic cod (Gadus morhua) with estimation of the acoustic and trawl dead zones     

McQuinn  Ian H.; Simard  Yvan; Stroud  Thomas W.F.; Beaulieu  Jean-Louis; Walsh  Stephen J. 《ICES Journal of Marine Science》2005,62(1):93-106

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Mineralogical and geochemical evolution of the 1982–1983 Galunggung eruption (Indonesia)     

Marie-Christine Gerbe  Alain Gourgaud  Olgeir Sigmarsson  Russell S Harmon  Jean-Louis Joron  Ariel Provost 《Bulletin of Volcanology》1992,54(4):284-298

Pyroclastic deposits from the 1982–1983 eruption of Galunggung volcano (Java, Indonesia) reflect preeruptive magmatic evolution which is of interest because of: (1) its duration of nine months, compared to a few hours or days for most historical eruptions; (2) the diversity of eruptive styles, from ash and scoria flows to phreatomagmatic explosions, and to the strombolian activity that marked the end of the eruption; and (3) the progressive variation in chemical composition with time, from andesite (58 wt.% SiO₂) to high-Mg basalt (47 wt.% SiO₂). The 1982–1983 Galunggung basalts are rather primitive: 10 to 12 wt% MgO, 180 to 200 ppm Ni and 550 to 700 ppm Cr. Despite the presence of about 40% phenocrysts, they may represent the most primitive basalts recognized in western Java. Basalts contain phenocrysts of olivine (Fo_90-80), diopside-salite, and plagioclase (An_95-75). Andesites contain plagioclase (An_80–60), augite, hypersthene (En_67-64), and titanomagnetite. The distribution of mineral compositions in each petrographic type is nearly unimodal, although scarce plagioclase and olivine xenocrysts have been observed. Abundance of gabbroic cumulates associated with the pyroclastic flows and evolution of mineral compositions from high-Mg basalts to andesites support crystal fractionation as the main differentiation mechanism, although magma mixing of basaltic andesite and andesite cannot be excluded. Major and trace element trends, which display rough decreases of MgO, CaO, Ni, Cr with increasing degree of differentiation and also linear positive correlations of hygromagmaphile elements, are compatible with both processes. However, some discrepancies are observed between major and trace element modelling, which may be explained to some extent by the influence of in situ crystallization and/or magma mixing. The constancy of ¹⁴³Nd/¹⁴⁴Nd (0.51286±3), ²³⁰Th/²³²Th (0.65±0.02), Th/U (4.08±0.07) ratios, and to a lesser extent ¹⁸O values (+5.8 to +6.4 % SMOW) and ⁸⁷Sr/⁸⁶Sr ratios (0.70440 to 0.70468) is compatible with a magmatic evolution through fractional crystallization without significant crustal contamination. Nevertheless low-¹⁸O and high ⁸⁷Sr/⁸⁶Sr values in basaltic andesites may be due to the introduction of meteoric fluids into the Galunggung magma.  相似文献   

Analysis of the experimental compressibility of deep water marine sediments from the Gulf of Guinea     

Mahdia Hattab  Jean-Louis Favre 《Marine and Petroleum Geology》2010

This study strives to analyze the compressibility of deep water marine sediments originating from the Gulf of Guinea. Our approach is multi-scaled and, on the macroscopic level, based on two equations which link the overburden effective stress with the liquidity index, the Biarez & Favre equation on the one hand, and the Burland equation on the other hand (after calculation of the ICL expression as a function of the I_L parameter). On the local level, the evolution of the microstructures is analysed and compared with GoG remoulded clay. Two additional observation techniques have been used, the scanning electron microscope and the mercury intrusion porosimetry.  相似文献   

Practical versus absolute salinity measurements: New advances in high performance seawater salinity sensors     

Philippe Grosso  Marc Le Menn  Jean-Louis De Bougrenet De La Tocnaye  Zong Yan Wu  Damien Malardé 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(1):151-156

Optical salinity sensors described here measure directly the seawater refractive index and thus enable a measurement of the seawater density and composition variation. We detail the measurement dependence to environmental parameters (in particular temperature and pressure) compared to conductivity sensors, and demonstrate that it may be advantageous to directly measure refractive index rather than electrical conductivity and so obtain a more direct route to density and absolute salinity.  相似文献   

Permian granites in the Pyrenees: the Aya pluton (Basque Country)     

Yoann Denèle  Jean‐Louis Paquette  Philippe Olivier  Pierre Barbey 《地学学报》2012,24(2):105-113

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Antimony speciation in saline hydrothermal fluids: A combined X-ray absorption fine structure spectroscopy and solubility study   总被引：2，自引：0，他引：2  

Gleb S. Pokrovski  Anastassia Yu. Borisova  Jean-Louis Hazemann  Marie Tella 《Geochimica et cosmochimica acta》2006,70(16):4196-4214

Solubility of senarmontite (Sb₂O₃, cubic) in pure water and NaCl-HCl aqueous solutions, and local atomic structure around antimony in these fluids were characterized using in situ X-ray absorption fine structure (XAFS) spectroscopy at temperatures to 450 °C and pressures to 600 bars. These experiments were performed using a new X-ray cell which allows simultaneous measurement of the absolute concentration of the absorbing element in the fluid, and atomic environment around the absorber. Results show that aqueous Sb(III) speciation is dominated by the complex in pure water, mixed Sb-hydroxide-chloride complexes in acidic NaCl-HCl solutions (2 m NaCl-0.1 m HCl), and by Sb-chloride species in concentrated HCl solutions (3.5 m HCl). Interatomic Sb-O and Sb-Cl distances in these complexes range from 1.96 to 1.97 Å and from 2.37 to 2.47 Å, respectively. These structural data, together with senarmontite solubility determined from XAFS spectra, were complemented by batch-reactor measurements of senarmontite and stibnite (Sb₂S₃, rhombic) solubilities over a wide range of HCl and NaCl concentrations from 300 to 400 °C. Analysis of the whole dataset shows that Sb(III) speciation in high-temperature moderately acid (pH > 2-3) Cl-rich fluids is dominated by mixed hydroxy-chloride species like Sb(OH)₂Cl° and Sb(OH)₃Cl⁻, but other species containing two or three Cl atoms appear at higher acidities and moderate temperatures (?300 °C). Calculations using stability constants retrieved in this study indicate that mixed hydroxy-chloride complexes control antimony transport in saline high-temperature ore fluids at acidic conditions. Such species allow for a more effective Sb partitioning into the vapor phase during boiling and vapor-brine separation processes occurring in magmatic-hydrothermal systems. Antimony hydroxy-chloride complexes are however minor in the neutral low- to moderate-temperature solutions (?250-300 °C) typical of Sb deposits formation; the antimony speciation in these systems is dominated by Sb(OH)₃ and potentially Sb-sulfide species.  相似文献   

Bioaccumulation of heavy metals and radionuclides from seawater by encased embryos of the spotted dogfish Scyliorhinus canicula     

Jeffree RA  Warnau M  Oberhansli F  Teyssie JL 《Marine pollution bulletin》2006,52(10):1278-1286

Encased embryos of spotted dogfish Scyliorhinus canicula absorbed six radio-isotopes (241Am, 109Cd, 57Co, 134Cs, 54Mn and 65Zn) directly from seawater during short-term experimental exposure, demonstrating the permeability of the egg-case to these contaminants. Embryo to water concentration factors (CFs) ranged from 0.14 for 134Cs to 7.4 for 65Zn. The 65Zn and 57Co CFs increased exponentially with embryo length, whereas the CF for 109Cd declined with length. Among different components of the encased embryo the egg case was the major repository (69-99%) of all six radio-isotopes that were distributed throughout its wall. Egg-case CFs were as high as 10(3) for 57Co and 65Zn, making it the major source of gamma radiation exposure to the embryo and potentially of radio-isotopes for continued absorption by the embryo, following the uptake phase of the experiment. The patterns of uptake by the egg-case approximated linearity for most isotopes and loss rates were isotope-specific; egg-case biokinetics were not greatly affected by the viability of the contained embryo. Within the embryo initial data on radio isotopic distribution show that the skin is their major site of uptake, as previously demonstrated for juveniles.  相似文献   

Structural control of the distribution of trace elements between silicates and hydrothermal solutions     

Marcel Volfinger  Jean-Louis Robert 《Geochimica et cosmochimica acta》1980,44(10):1455-1461

Over several years many partition coefficients have been measured between framework silicates, sheet silicates and hydrothermal solutions. Only trace alkaline cations are considered in the present work. It is well known that the difference between ionic radii of the trace cation and the major cation is replaces is not satisfactory for a good correlation with the partition coefficients P_X. A structural parameter δ_c is therefore defined, taking into consideration the adaptation of the trace cation to the cavity in which it occurs. This cavity may be the entire site of the major element, or a part of this site in the case of small cations, or a structural cavity located out of the alkali-ion site. The adaptation parameter δ_c is the difference between the ionic radius of the trace cation and the radius of that cavity. This paper shows that the partition coefficient P_X of the trace alkali-ion from the hydrothermal solution is an exponential function of the adaptation parameter δ_c, whatever the silicate may be.  相似文献   

The worldwide character of the 1969–1970 impulse of the secular acceleration rate     

Jean-Louis Le Mouël  Joël Ducruix  Chau Ha Duyen 《Physics of the Earth and Planetary Interiors》1982,28(4):337-350

This paper continues earlier studies to ascertain whether the distribution of the 1969–1970 jump of the secular variation rate has a worldwide character. The geometry of the jump presents some similarities with the geometry of the secular variation itself. We give a new estimation of the westward drift rate and information about spatial and temporal variations of the secular variation field.  相似文献