Les modalités de la reproduction de la coque (Cerastoderma edule) sur le littoral français de la Manche et de l'Atlantique
Le cycle sexuel de Cerastoderma edule a été étudié durant l'année 1987 sur plusieurs sites le long du littoral atlantique français, de la baie de Somme au bassin d'Areachon. Cette étude vise à définir les modalités de la ponte et les facteurs qui la régissent, afin d'identifier à ce niveau, les causes de la variabilité du recrutement. Dans ce but, une méthode commune est mise en œuvre. Elle repose essentiellement sur la reconnaissance des stades de maturité sexuelle et sur les fluctuations de l'indice de condition. Les pontes peuvent être : précoce, printanière, estivale ou tardive, et, selon leur nombre et leur importance, variables selon les sites. La première ponte apparaît toujours en réponse au stimulus thermique qui correspond, au printemps, à l'amélioration des conditions climatiques et trophiques. A l'intérieur de l'espace latitudinal défini, il n'apparaît pas de net gradient au niveau des pontes, ce qui démontre que celles-ci ne sont pas déclenchées par une valeur définie de la température. L'efficacité de la ponte printanière est liée à une valeur seuil de l'indice de condition. Le nombre et l'intensité des pontes estivales et automnales sont fonction de l'importance de la ponte printanière. Il en résulte une forte variabilité dans les conditions de recrutement. Dans l'optique recherchée, certains principes prédictifs peuvent cependant être avancés.
(Aquatic Living Resources. vol. 3, n° 0990-7440, pp. 29 - 41, 01/01/1990)
LOPS, IRD, IFREMER, INSU - CNRS, UBO EPE, CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, LIENSs, INSU - CNRS, ULR, CNRS
Alkylated phenanthrene distribution in artificially matured kerogens from Kimmeridge clay and the Brent Formation (North Sea)
Kerogen and extractible organic matter from immature Kimmeridge clay and Brent coal were heated at different temperatures (270-500°C) under conditions to mimic natural maturation. Aromatic fractions have been examined for their phenanthrene compound distribution. Phenanthrene indices based on methylphenanthrenes (MP) and dimethylphenanthrenes (DMP) exhibit very sensible changes in the applied temperature range. However, at high temperatures (about 450°C and more) possible thermal degradation of phenanthrene compounds produces a decrease in the values of the indices. Experimental data obtained in this study are compared and discussed with data obtained on thermal evolution performed on total rocks. Vitrinite reflectance values measured on artificially matured coals are also tentatively correlated with phenanthrene ratios. Theoretical thermodynamic calculations on MP compounds confirm also the relative thermal stability of the individual isomers. \textcopyright 1990.
(Organic Geochemistry. vol. 16, n° 0146-6380, pp. 167--173, 30/04/1990)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPTC, UB, CNRS
Cadmium contamination of tissues and organs of delphinids species (Stenella attenuata)—Influence of biological and ecological factors
Based on a sample of 27 dolphins (Stenella attenuata) captured in the Eastern tropical zone of the Pacific Ocean, this study was carried out to analyze the cadmium accumulation levels and distribution in 12 organs or tissue samples. The average cadmium concentrations were between 0.2 mg Cd · kg−1 in the brain and muscle and 48 mg Cd · kg−1 in the kidneys. For most of organs and tissues the average values were between 1 and 5 mg Cd · kg−1. Kidneys, liver, muscle, and intestine contained almost 85% of the total cadmium burden of all tissues considered in this study. Most of the biological and ecological factors taken into account (age, sex, total weight, and length of the dolphins, weight of the organs, place and date of capture) interacted with the cadmium concentrations and burdens in the collected organs or tissues. Three factors appear to be of prime importance: age, body weight, and geographical location of the area of capture.
(Ecotoxicology and Environmental Safety. vol. 20, n° 0147-6513, pp. 290-306, 30/04/1990)
ENSC, IMS, UB, CNRS, IMS, UB, CNRS, UN, IUML, UM, UA, UN, ECN, UBS, IFREMER, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Microfluorimetry applied to organic diagenesis study.
Microfluorimetric analyses, using new procedures have been applied on three sedimentary basins, each of them exhibiting a specific thermal history. The results have been compared to other optical and geochemical maturity parameters. It appears that the spectral fluorescence parameters cannot be used as rank parameters, because of their complex evolution with increasing diagenesis. However, they are better parameters than vitrinite reflectance for thermal maturity assessment as far as hydrocarbon generation is concerned. For instance, it is shown that different types of fluorescent materials release hydrocarbons at different levels of thermal evolution in a given series. On the other hand, alteration analyses appear to be efficient and objective tools for the punctual detection of hydrocarbons in a sample.
(Organic Geochemistry. vol. 13, n° 0146-6380, pp. 4-6, 1163-1167, 30/04/1988)
CSTJF, [Total Energies. Anciennement : Total, TotalFina, TotalFinaElf], EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, G2R, UHP, INPL, CREGU, CNRS, ISTO, INSU - CNRS, UO, CNRS, [Total Fina ELF]
Trace analysis of aromatic compounds in natural samples by Shpol'skii spectroscopy
Low molecular weight aromatic compounds (acenaphthene, acenaphthalene, fluorene, phenanthrene and anthracene) were difficult to detect due to their low fluorescence quantum yield. To evaluate the accuracy of this method, we have analyzed several organic extracts (diesel particulate, air particulate). The results (imprecision less than 15%) obtained by Shpol'skii spectroscopy have been compared with values obtained by other analytical methodologies (HPLC coupled with fluorescence detection, GC coupled to mass spectrometry). Good agreement is observed among the three analytical techniques, demonstrating the reliability of Shpol'skii spectroscopy for quantitative analysis.
(Journal of research of the National Bureau of Standards. vol. 93, pp. 441--443, 30/04/1988)
LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Distribution of methylperylene isomers in selected sediments
Surface and deep sediment extracts, containing perylene compounds, have been examined by High Resolution Shpol'skii Spectroscopy. The first identification of the three methylperylene isomers is reported and indicates the predominance of 2-methylperylene among the methylperylene isomer distributions at any maturation stage. Perylene itself was nevertheless always found to be the most abundant perylene compound. \textcopyright 1988.
(Geochimica et Cosmochimica Acta. vol. 52, n° 0016-7037, pp. 901--907, 30/04/1988)
LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPPM, UB
Relationship between rank and distribution of methylaromatic hydrocarbons for condensates of different origins
Aromatic hydrocarbon fractions from thirty gas condensates have been analysed by capillary GC and high resolution Shpol'skii spectroscopy for the determination of the relative distribution in methylphenanthrene (MP), dimethylphenanthrene (DMP) and methylpyrene (MPy) series. The measured maturity indices, MPI, DMPI and MPyI which appeared previously suitable for rocks, coals and crude oils have been tested for the recognition of rank levels of condensates. MPI and DMPI exhibit a remarkedly similar evolution which allows the differentiation of the samples analysed in these works. Such studies extend the applicability of alkylaromatic hydrocarbon ratios to the characterization of maturity level of condensates which range from immature-marginally mature to overmature samples, partially biodegraded or not. \textcopyright 1988.
(Organic Geochemistry. vol. 13, n° 0146-6380, pp. 1115--1121, 30/04/1988)
LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Identification of alkyphenanthrenes in shale oil and coal by liquid and capillary gas chromatography and high-resolution spectrofluorimetry (shpol'skii effect)
The combination of three high-performance liquid chromatographic steps performed on shale and coal extracts allows the collection of subfractions containing one to three C2-phenanthrene isomers. The identification was made by comparison with retention indices, gas chromatographic-mass spectrometric data and Shpol'skii emission spectra of the 30 reference C2-phenanthrenes that have been synthesized. \textcopyright 1987.
(Journal of Chromatography A. vol. 395, n° 0021-9673, pp. 217--228, 30/04/1987)
LPTC, UB, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
De la fin du Villafranchien au début du Soltanien : exemple d'évolution des paléoenvironnements du Maroc occidental et oriental.
Les observations présentées se fondent sur un cadre chronologique raisonné du Quaternaire marocain liant les données océaniques et continentales. Elles intéressent le domaine mésétien et le domaine intra-atlasique. Elle conclut à la perduration des styles morphosédimentaires du Villafranchien au Tensiftien, puis à un accroissement de l'aridification.
(Bulletin de l'Association de géographes français, n° 0004-5322, pp. 20 pages, 30/04/1985)
ASM, UPVM, CNRS, MC, PACEA, UB, CNRS
Approches sédimentologique et géophysique des accumulations turbiditiques : l'éventail profond du Cap-Ferret (Golfe de Gascogne), la série des grès d'Annot (Alpes-de-Haute-Provence)
A l'aide de deux exemples, l'un actuel (l'éventail du Cap-Ferret), l'autre ancien (la série des Grés d'Annot) et par des méthodes d'approche complémentaires (analyse morphologique, sédirnentologique, interprétation sismique) sont caractérisés les facteurs et les processus dynamiques qui conditionnent l'édification des appareils turbiditiques. Le cadre morphostructural de la marge continentale, le climat et les variations du niveau marin déterminent le volume et la nature de l'alimentation terrigène, la dynamique des écoulements gravitaires et par conséquence les modalités de construction et d'évolution des appareils turbiditiques. L'éventail du Cap-Ferret, éloigné des sources terrigènes grossières se caractérise par l'importance des dépôts turbiditiques silto-argileux de débordement, fortement influencés par l'accélération complémentaire de Coriolis. Inversement les Grés d'Annot se mettent en place à pro* ximité des sources terrigènes grossières et forment, dans des dépressions/des remplissages en "onlap", constitués de lobes gréseux très aplatis.
(02/07/1983)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS