An application of Iatroscan thin-layer chromatography with flame ionization detection—lipid classes of microorganisms as biomarkers in the marine environment     

M. Goutx  C. Gerin  J.C. Bertrand 《Organic Geochemistry》1990,16(4-6)

Iatroscan TLC-FID combines the separatory capabilities of thin-layer chromatography (TLC) (on silica coated chromarods) with the possibility of quantitation by flame ionization detection (FID). It can be used to separate lipid extracts into classes of compounds ranging from neutral to polar products. The rapidity with which this system provides lipid class profiles from small samples makes it particularly useful in oceanographic studies where routine analyses of large numbers of samples are required. Lipid classes were analysed in 4 marine bacterial strains grown on various substrates and 10 microalgae isolated from the marine environment and grown in batch cultures. Data on lipid composition of these microorganisms were obtained and compared to literature data. Results show that ratios between classes of compounds within the different groups of microorganisms were characteristic enough to constitute a good print of bacterial or phytoplankton sources in organic matter in sea water. In a preliminary study, phospholipid classes from a bacterial strain and a microalga were separated. Results show that the determination of ratios between phospholipid classes in organic matter could represent an improvement in the utilization of lipid classes as biomarkers.  相似文献   

Correlations among the reflectances of vitrinite, chitinozoans, graptolites and scolecodonts     

Rudolf Bertrand 《Organic Geochemistry》1990,15(6)

Paleozoic marine sequences sampled in outcrops and wells of northeastern Gaspe Peninsula (Quebec Appalachians) yield kerogen composed in part of vitrinite and zooclasts (chitinozoans, scolecodonts and graptolites) on which reflectance measurements were made.The comparison between means of random measurements show that reflectance of chitinozoans is similar to that of telinite (vitrinite with a cellular texture) and that the reflectance of scolecodonts is significantly lower than that of telinite in the lower range of studied values. At higher reflectivities differences decrease but, at the end of the condensate gas zone reflectancea are not yet identical. As shown by previous studies, reflectance of graptolites is slightly less than that of telinite.Pyrobitumen reflectance is related to the lithology of the host-rock and no generalized correlation can be established between the reflectance of pyrobitumen and that of vitrinite.  相似文献   

The effects of non-sphericity in diagnosis of solar and stellar atmospheres     

Jean-Claude Pecker 《Solar physics》1996,169(2):277-291

Between the interplanetary medium, filled by winds, magnetic structures, etc., and the interior of stars, opaque, and dominated heavily by the gravitational spherical field, the stellar atmosphere is a place where the true physical equilibrium, on the inside, sufficiently described by the parameters L, M, R, and the chemical composition X, Y, Z, is progressively changing into a situation far for equilibrium, which needs many more parameters to be properly described.The assumption that the equilibrium situation was dominating in the atmosphere has been generally accepted during the first half of this century. Since 1950 or so, we progressively learnt that the thermodynamical equilibrium (TE), and even the local thermodynamical equilibrium (LTE), are far from being actually in existence, that the radiative equilibrium (RE) is not actually perfect, convection, diffusion, magnetism, dissipation processes... playing a non-negligible part in the energy transport, that the hydrostatic equilibrium (HE) is only an approximation, as the convection and the magnetism are affecting the atmospheric layers, that neither the sphericity of atmospheric layers (plane-parallel hypothesis: PP) is achieved, nor the homogeneity of stellar iso- layers. During the 1950s and following decades, we began to suspect these difficulties and their consequences. In this paper, we turn towards a new consequence of the last-mentioned effect: the influence of non-sphericity and inhomogeneity upon the stellar (and solar perhaps) abundances of elements.Dedicated to Cornelis de Jager  相似文献   

The Perte-du-Rhône Formation,a new Cretaceous (Aptian-Cenomanian) lithostratigraphic unit in the Jura mountains (France and Switzerland)     

Antoine Pictet  Michel Delamette  Bertrand Matrion 《Swiss Journal of Geoscience》2016,109(2):221-240

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Experimental and Numerical Study of Wind and Turbulence in a Near-Field Dispersion Campaign at an Inhomogeneous Site     

Xiao Wei  Eric Dupont  Eric Gilbert  Luc Musson-Genon  Bertrand Carissimo 《Boundary-Layer Meteorology》2016,160(3):475-499

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Facies system of the Eastern Barents Sea since the last glaciation to present     

Ivar Murdmaa  Elena Ivanova  Jean-Claude Duplessy  Michael Levitan  Tatyana Khusid  Maria Bourtman  Galina Alekhina  Tatyana Alekseeva  Michael Belousov  Valentina Serova 《Marine Geology》2006,230(3-4):275-303

Twenty-two sediment cores raised from the central and eastern parts of the Barents Sea have been studied to reconstruct the evolution of the facies system since the Late Weichselian glaciation. Multiproxy records reveal four lithostratigraphic units, which reflect major development stages of paleoenvironments. Age control is provided by 23 AMS ¹⁴C dates for Holocene sections of four cores. Continental moraine deposits of the last glaciation are overlain by proximal glaciomarine facies of the initial deglaciation phase. During this phase, the Barents Sea ice sheet detached from the ground resulting in seawater penetration into troughs, iceberg calving, deposition of IRD and fine-grained glacier meltwater load in newly formed marine basins. The main deglaciation phase is characterized by pulsed sedimentation from various gravity flows resulting in accumulation of distal glaciomarine facies comprising laminated clay and sand sequences with minor IRD. Redistribution of fine-grained suspended matter by bottom currents and brine-induced nepheloid flows combined with biogenic processes and minor ice rafting caused facies diversity of the Holocene marine sediments. The Holocene facies of shelf depressions reflect rather high, but variable productivity responding to climate changes and variations of Atlantic water inflow into the Barents Sea.  相似文献   

Pasisar: Performances of a High and Very High Resolution Hybrid Deep-Towed Seismic Device     

Nouzé  Hervé  Sibuet  Jean-Claude  Savoye  Bruno  Marsset  Bruno  Thomas  Yannick 《Marine Geophysical Researches》1997,19(5):379-395

The Pasisar seismic acquisition system combines a source at the sea surface and a deep-towed single channel streamer. This unconventional device geometry reduces the width of the first Fresnel zone which increases the lateral resolution. However, the device acquisition geometry generates artifacts on seismic profiles and induces large incidence angles of the seismic signal. A specific processing sequence must be applied to the data to obtain a readable seismic section. Penetration of the seismic signal depends on the energy of the signal reaching the seafloor and on its incidence angle. Because of smaller source energy, 800 Joules Sparker data cannot be acquired in water depth larger than 1500 m for example, whereas there is no depth limit for the use of this system with air gun sources. Differential acoustic absorption of seismic frequencies (below 1000 Hz) in the water column is negligible when compared with wave fronts expansion. Thus, the horizontal resolution of any seismic system strongly depends on the frequency spectrum of the seismic source and on the travel distances. Pasisar and conventional seismic profiles being usually simultaneously recorded, we illustrate the interest of using a hybrid seismic device by comparing horizontal resolutions as well as signal-to-noise ratio obtained with both the Pasisar and conventional systems. In addition, by carefully picking time arrivals of a reflection on simultaneously recorded surface and deep-towed seismic records, it is possible to estimate the average interval seismic velocity. We present the simplified example of a horizontal reflector.  相似文献   

Interactions between fish and fisher's spatial distribution and behaviour: an empirical study of the anchovy (Engraulis ringens) fishery of Peru   总被引：1，自引：0，他引：1  

Bertrand  Sophie; Diaz  Erich; Niquen  Miguel 《ICES Journal of Marine Science》2004,61(7):1127-1136

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Assessment of wind-forcing impact on a global wind-wave model using the TOPEX altimeter     

Hui Feng  Doug Vandemark  Yves Quilfen  Bertrand Chapron  Brian Beckley 《Ocean Engineering》2006,33(11-12):1431-1461

The study presents assessment of an operational wave model (Wavewatch III), focusing upon the model sensitivity to wind-forcing products. Four wind fields are used to drive the model, including the NCEP/NCAR reanalysis and three other products that assimilate various satellite wind measurements having high spatial resolution, including the QuikSCAT scatterometer. Three wave field statistics: significant wave height, mean zero-crossing wave period, and mean square slope are compared with collocated TOPEX altimeter derivatives to gauge the relative skill of differing wind-forced model runs, as well as to demonstrate an extended use of the altimeter beyond simply supplying wave height for wave model validation and assimilation. Results suggest that model output is critically sensitive to choice of the wind field product. Higher spatial resolution in the wind fields does lead to improved agreement for the higher-order wave statistics.  相似文献   

Neogene exhumation and relief evolution in the eastern Betics (SE Spain): Insights from the Sierra de Gador          下载免费PDF全文

Marianne Janowski  Nicolas Loget  Cécile Gautheron  Jocelyn Barbarand  Nicolas Bellahsen  Jean Van Den Driessche  Julien Babault  Bertrand Meyer 《地学学报》2017,29(2):91-97

The Betics are a key area to study an orogenic landscape disrupted by late‐orogenic extension. New low‐temperature thermochronology (LTT) data (AHe and AFT) coupled with geomorphic constraints in the Sierra de Gador (Alpujarride complex) are used to reconstruct the cooling history and evolution of relief during the Neogene. We document three stages: (1) a fast cooling event between 23 and 16 Ma associated with the well‐known extensive tectonic exhumation of the Alpujarride unit, (2) a period of slow cooling between 16 and 7.2 Ma related to a planation event and (3) a post‐7.2 Ma surface uplift associated with the inversion of the Alboran domain undetected by LTT. The planation event followed by this late uplift can explain the occurrence of inherited low‐relief surfaces overlain by Tortonian–Messinian platform deposits at the top of the range. Finally, we propose that the Sierra de Gador is a more transient landscape than the nearby Sierra Nevada.  相似文献