Spatio-temporal changes in totally and enzymatically hydrolyzable amino acids of superficial sediments from three contrasted areas     

Antoine Grémare  Dimitri Gutiérrez  Jean Michel Amouroux  Gilles Vétion 《Progress in Oceanography》2005,65(1):89-111

Spatio-temporal changes in totally and enzymatically hydrolyzable amino acids (THAA and EHHA) and EHAA/THAA ratios of superficial sediments were assessed during 1997-1999 in three areas (i.e., the Gulf of Lions, the Bay of Biscay, and Central Chile) differing in their primary productivity. In all three areas, and even off Central Chile where a strong El Niño event took place during 1997-1998, spatial changes were always much greater than temporal ones. The factors affecting the spatial distributions of amino acid concentrations differed among areas. In the Gulf of Lions, sediment granulometry was apparently the most important driving force of THAA, EHAA, and EHAA/THAA, and there was no marked difference between stations located on the open slope and those in submarine canyons. Conversely, in the Bay of Biscay, there were clear differences between the stations located off Cap-Breton, on the open slope, and those in the Cap-Ferret canyon; the latter two featuring lower EHAA and THAA but higher EHAA/THAA. This pattern is likely to result from the predominance of different sources of organic matter and especially from the importance of continental inputs to the Cap-Breton canyon. Off Central Chile, amino acid concentrations and ratios were both maximal around 100 m depth, probably reflecting the interaction between the primary productivity gradient and the presence of an oxygen minimum zone (OMZ) reducing the degradation of sedimentary organics. When comparing the average values collected in the three areas studied, THAA and EHAA were highest in Central Chile, intermediate in the Bay of Biscay and lowest in the Gulf of Lions. EHAA/THAA ratios were also highest in Central Chile but were lowest in the Bay of Biscay. Differences between the Gulf of Lions and the Bay of Biscay could have been affected by sampling design. In Central Chile, the use of labile organic carbon to total organic carbon (C-LOM/TOC) and EHAA/THAA as indices of organic matter lability led to very similar results. This was not the case in the Bay of Biscay. It is therefore argued that the use of C-LOM/TOC should be restricted to highly productive areas.  相似文献   

Relationship between cod fishery activities and the population of herring gulls on the North Shore of the Gulf of St Lawrence, Quebec, Canada     

Chapdelaine  Gilles; Rail  Jean-Francois 《ICES Journal of Marine Science》1997,54(4):708-713

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Agonistic effect of imidazole and triazole fungicides on in vitro oocyte maturation in rainbow trout (Oncorhynchus mykiss)     

Gilles Monod  Hlne Rime  Julien Bobe  Bernard Jalabert 《Marine environmental research》2004,58(2-5):143

The purpose of the present study was to assess the in vitro effect of some imidazole (prochloraz, imazalil) and triazole (epoxiconazole) agricultural fungicides on gonadotropin-induced oocyte maturation in rainbow trout. Results show that prochloraz, epoxiconazole and imazalil strongly potentiated the induction of oocyte maturation by gonadotropin in a dose-dependent manner. Furthermore, 10⁻⁵ M prochloraz and epoxiconazole alone induced oocyte maturation. The mRNA biosynthesis inhibitor, actinomycin , completely inhibited oocyte maturation induced by fungicides, suggesting that the gonadotropin-like effect of these chemicals is at least dependent on de novo gene expression.  相似文献   

The multivariate (co)variogram as a spatial weighting function in classification methods   总被引：1，自引：0，他引：1  

Gilles Bourgault  Denis Marcotte  Pierre Legendre 《Mathematical Geology》1992,24(5):463-478

The multivariate variogram and the multivariate covariogram are used as spatial weighting functions for forming spatially homogeneous groups automatically. The groups are created after either deflating similarities between distant samples with the multivariate covariogram or by inflating dissimilarities between distant samples with the multivariate variogram. These approaches can be seen as generalization of the Oliver and Webster proposal. Two data sets show the efficiency of the two weighting functions when compared to the classical approach which does not take spatial information into account. In one case study, the weighting of similarities by the multivariate covariogram showed more interpretable results than the weighting of dissimilarities by the multivariate variogram.  相似文献   

Orbital imprint on Holocene palaeohydrological variations in west‐central Europe as reflected by lake‐level changes at Cerin (Jura Mountains,eastern France)     

Michel Magny  Gilles Bossuet  Pascale Ruffaldi  Aurélie Leroux  Jacques Mouthon 《第四纪科学杂志》2011,26(2):171-177

This paper presents a lake‐level record for the Holocene at Lake Cerin (Jura Mountains, eastern France). It is based on a range of sedimentological techniques validated in previous studies, with a combination of systematic lithostratigraphic investigations of the infillings accumulated in the lacustrine basin, and sediment analyses of two selected cores. The chronology is based on 10 radiocarbon dates and pollen stratigraphy. On a millennial scale, the Cerin lake‐level record shows three distinct successive phases characterised by higher lake‐level conditions until ca. 9000 cal. a BP, followed by a maximal lowering at ca. 9000–8500 cal. a BP, and a progressive rise until the present. This rise was punctuated by centennial‐scale fluctuations, with major events around 4000, 2800 and after 1500 cal. a BP. Considered on a multimillennial scale, the general pattern of palaeohydrological changes reconstructed at Cerin reflects the impact of orbitally driven summer insolation. This is in agreement with other regional and extra‐regional palaeoclimatic records, although every record shows peculiarities in timing and shape depending on the proxy used for reconstruction. In this general context, centennial to multicentennial oscillations appear to have been second‐order events in comparison with the major influence of the orbital factor. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Fatty acid transfer in the food web of a coastal Mediterranean lagoon: Evidence for high arachidonic acid retention in fish     

Apostolos-Manuel Koussoroplis  Alexandre Bec  Marie-Elodie Perga  Emmanuil Koutrakis  Gilles Bourdier  Christian Desvilettes 《Estuarine, Coastal and Shelf Science》2011,91(3):450-461

The transfer of fatty acids (FAs) in the food web of a Mediterranean lagoon was studied using FA compositional patterns across several trophic levels. The structure of the food web was inferred from C and N stable isotopes values and an isotope mixing model was used in order to estimate the relative contribution of the different potential food sources to the biomass of consumers. Bidimensional plots of FA composition of food web components against their δ¹⁵N values indicated a general trend of increasing proportions of highly unsaturated fatty acids (HUFAs) with increasing trophic levels while the proportions of saturated fatty acids (SAFAs) and 18-carbon polyunsaturated fatty acids (PUFAs) decreased. Using the relative contributions of food sources to consumers and their FA compositions, a model was built in order to estimate the PUFA composition of consumer mixed diets which was compared to consumer PUFA profiles. The latter allowed the identification of the PUFAs which were mostly enriched/retained in consumer lipids. There was a surprisingly high retention of arachidonic acid (ARA), a trend which challenges the idea of low ARA needs in marine fish and suggests the important physiological role of this essential FA for fish in estuarine environments.  相似文献   

Âge 40K/40Ar,Carbonifère inférieur,du magmatisme basique filonien du synclinal paléozoïque de Tin Serririne,Sud-Est du Hoggar (Algérie)     

Hamou Djellit  Hervé Bellon  Aziouz Ouabadi  Mohamed E.M. Derder  Bernard Henry  Boualem Bayou  Allaoua Khaldi  Kamal Baziz  Mounir K. Merahi 《Comptes Rendus Geoscience》2006,338(9):624-631

Palaeozoic formations of the Tassilis Oua-n-Ahaggar (southeastern Hoggar) include magmatic rocks in the Tin Serririne syncline. Slight contact metamorphism of the overlying bed and studies of anisotropy of magnetic susceptibility of these rocks show that the latter correspond to sills and NW–SE or north–south dykes. ⁴⁰K/⁴⁰Ar dating of separated feldspars and whole rock for one sample and of whole rock for two other samples give a mean age of $347.6\pm 16.2\text{Ma}$ (at the 2-σ level), thus corresponding to a Lower Carboniferous (Tournaisian) age. Taking into account both the age of this magmatism and the stratigraphic and structural data for this region suggests that dolerites were emplaced within distensive zones that are related to the reactivation of Panafrican faults. To cite this article: H. Djellit et al., C. R. Geoscience 338 (2006).  相似文献   

Present-day deformation of the French northwestern Alps/southern Jura mountains: comparison between historical triangulations     

François Jouanne  Gilles Ménard  Dominique Jault 《Geophysical Journal International》1994,119(1):151-165

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Aspects géochronologiques(K-Ar)de l'activité volcanique dans l'île de moorea, Pacifique Central     

Herv Bellon  Franois Blanchard 《Tectonophysics》1981,72(1-2)

Moorea volcanic island (Central Pacific) shows particular characteristics: it has been built by synchronous emissions (shown by radiometric K-Ar data) of basic volcanics (basalts and K hawaiites) and of very abundant evoluted lavas (K benmoreites), systematically aphyric, but containing ferromagnesian xenocrysts.Radiometric K-Ar data also underline the intricate and multistage character of the island building. Its genesis would be explained in the light of a fractional melting process.

Résumé

L 'fle volcanique de Moorea (Pacifique Central) présente la particularité d'avoir étéédifiée par la coémission (démontrée par les données radiométriques K-Ar) de roches basiques (basaltes et K hawaiites) et de roches évoluées très abondantes (K benmoréites), systématiquement aphyriques, mais contenant des xénocristaux ferromagnésiens.Les données radiométriques K-Ar soulignent aussi le caractère complexe de l'empilement volcanique construit en plusieurs stades. Sa genèse pourrait être expliquée par un processus de fusion fractionnée.  相似文献   

Datations K-Ar de quelques laves du Rift-ouest de l'Afrique Centrale; implications sur l'évolution magmatique et structurale     

Dr. H. Bellon  A. Pouclet 《International Journal of Earth Sciences》1980,69(1):49-62

Résumé Douze nouvelles datations donnent quelques précisions sur l'histoire magmatique et structurale du rift-ouest de l'Afrique Centrale. Elles concernent des intrusions alcalines situées en bordure du rift et des laves du Sud-Kivu, du sud et de l'ouest des Virunga. Les intrusions alcalines sont datées du Cambrien, Permien, Crétacé et Paléocène. Elles sont liées à des grandes cassures crustales empruntées par le rift. Les premières laves, des basaltes sub-alcalins, apparaissent au Sud-Kivu à l'Eocène. Elles sont suivies par des basaltes alcalins, au Miocène puis au Pléistocène inférieur. Plus au nord, des lambeaux de volcanisme ancien sont datés de l'Oligocène supérieur, au Nord-Idjwi, et du Miocène moyen et supérieur, à l'ouest des Virunga. Ce sont des laves alcalines sodiques. Elles sont antérieures au volcanisme potassique, leucitique et néphélinitique des Virunga apparu à la fin du Pliocène, et encore actif. L'évolution chronologique du magmatisme et de la structure est discutée.

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Twelve new datings specify some further details about the magmatic and the structural framework of the Western Rift of Central Africa. They concern alkaline intrusions of the rift border and lavas from Southern Kivu, Southern and Western Virunga. The intrusions have Cambrian, Permian, Cretaceous and Paleocene ages. They are related to the great crustal faults followed by the rift. The early lavas, sub-alkaline basalts, appear in Southern Kivu at the Eocene. They are followed by alkaline basalts, at the Miocene, and then at the lower Pleistocene. To the north, some earlier volcanic remains of alkaline sodic composition have upper Oligocene ages in Northern Idjwi, and middle and upper Miocene ages in Western Virunga. They preceded the potassic, leucitic and nephelinitic volcanism of Virunga which appears at the end of the Pliocene and is still active. We discuss about the chronological magmatic and structural evolution.

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Zusammenfassung Zwölf neue Datierungen bestimmen genauer die magmatische und strukturelle Geschichte des Westrifts von Zentralafrika. Sie betreffen am Rand des Rifts liegende alkalische Intrusionen und Laven in Südkivu, südlich und westlich der Virunga. Die alkalischen Intrusionen datieren vom Kambrium, dem Perm, der Kreidezeit und dem Paläozän. Sie stehen in Beziehung zu den vom Rifting gewählten großen Erdrinderissen. Die ersten Laven, subalkalische Basalte, entstehen im Eozän im Südkivu. Dann kommen alkalische Basalte im Miozän und am Unterpleistozän. Nördlicher datieren ältere Vulkanausbrüche vom Oberoligozän im Nordidjwi und vom mittleren Miozän und höheren Miozän westlich der Virunga. Es sind alkalische Natronlaven. Sie sind älter als der kaliumreiche Vulkanismus mit Leucit und Nephelin des am Ende des Pliozäns entstandenen und noch aktiven Vulkanismus. Die chronologische Entwicklung des Magmatismus und der tektonischen Strukturen wird diskutiert.

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