Assessment of the effects of hydrocarbon contamination on the sedimentary bacterial communities and determination of the polar lipid fraction purity: Relevance of intact phospholipid analysis     

Nicolas Mazzella  Josiane Molinet  Agung Dhamar Syakti  Jean-Claude Bertrand  Pierre Doumenq   《Marine Chemistry》2007,103(3-4):304-317

This in situ study reports on the relevance of intact phospholipids as new biomarkers and highlights the limits of the classical fatty acid analysis after the hydrolysis of the polar lipid fraction. The analysis of polar lipid fractions revealed significant contributions of marine macrophytes with either non-phospholipid compounds (sulfoquinovosyl diacylglycerol) or with both non-bacterial phospholipid classes (phosphatidylcholine) and non-bacterial phospholipid molecular species (some molecular species of phosphatidylglycerol). The analysis of intact phospholipids showed also the predominance of gram-negative bacteria in sediments whereas the analysis of fatty acids alone cannot confirm such information. Lastly, as regard to the effects of petroleum hydrocarbons on the sedimentary bacterial communities, we observed a higher degree of saturation of the fatty acyl chains of the phospholipids extracted from sediment exposed to a massive and chronic crude oil contamination. Such a result was interpreted as an adaptive response resulting in higher membrane rigidity of the bacterial communities.  相似文献   

Combining indicator trends to assess ongoing changes in exploited fish communities: diagnostic of communities off the coasts of France   总被引：1，自引：1，他引：1  

Rochet  Marie-Joelle; Trenkel  Verena; Bellail  Robert; Coppin  Franck; Le Pape  Olivier; Mahe  Jean-Claude; Morin  Jocelyne; Poulard  Jean-Charles; Schlaich  Ivan; Souplet  Arnauld; Verin  Yves; Bertrand  Jacques 《ICES Journal of Marine Science》2005,62(8):1647-1664

  相似文献   

Tectonic Significance of the Taitung Canyon, Huatung Basin, East of Taiwan     

Jean-Claude Sibuet  Shu-Kun Hsu  Alain Normand 《Marine Geophysical Researches》2004,25(1-2):95-107

Since the beginning of formation of Proto-Taiwan, the subducting Philippine (PH) Sea plate has moved continuously through time in the N307° direction with respect to Eurasia (EU), tearing the EU plate. The subducting EU plate includes a continental part in the north and an oceanic part in the south. The boundary B between these two domains corresponds to the eastern prolongation of the northeastern South China Sea ocean-continent transition zone. In the Huatung Basin (east of Taiwan), the Taitung Canyon is N065° oriented and is close and parallel to B. Seismic profiles show that the southern flank of the canyon corresponds to a fault with a normal component of a few tens of meters in the sediments and possible dextral shearing. Several crustal earthquakes of magnitude >%6 are located beneath the trend of the Taitung Canyon and focal mechanisms suggest that the motion is right-lateral. Thus, faulting within the sedimentary sequence beneath the Taitung Canyon is a consequence of underlying dextral strike-slip crustal motions. As the continental part of the EU slab located north of B has been recently detached, some subsequent dextral strike-slip motion might be expected within the EU slab, along the ocean-continent transition zone, which is a potential zone of weakness. We suggest that the dextral strike-slip motion along the ocean-continent boundary of the EU slab might trigger the observed dextral strike-slip motion within the overlying PH Sea crust and the associated faulting within the sediments of the Huatung Basin, beneath the Taitung Canyon. An erratum to this article is available at .  相似文献   

Cross-scale analysis of cluster correspondence using different operational neighborhoods     

Yongmei Lu  Jean-Claude Thill 《Journal of Geographical Systems》2008,10(3):241-261

Cluster correspondence analysis examines the spatial autocorrelation of multi-location events at the local scale. This paper argues that patterns of cluster correspondence are highly sensitive to the definition of operational neighborhoods that form the spatial units of analysis. A subset of multi-location events is examined for cluster correspondence if they are associated with the same operational neighborhood. This paper discusses the construction of operational neighborhoods for cluster correspondence analysis based on the spatial properties of the underlying zoning system and the scales at which the zones are aggregated into neighborhoods. Impacts of this construction on the degree of cluster correspondence are also analyzed. Empirical analyses of cluster correspondence between paired vehicle theft and recovery locations are conducted on different zoning methods and across a series of geographic scales and the dynamics of cluster correspondence patterns are discussed.   相似文献   

Hazard appraisal and hazard-zone mapping of flooding and debris flowage in the Rio Combeima valley and Ibague city,Tolima Department,Colombia     

Jean-Claude Thouret  Christophe Laforge 《GeoJournal》1994,34(4):407-413

Since a state law issued in 1989, every big town in Colombia has to promote its own preparedness programme for disaster relief in the framework of the Oficina Nacional para la Atencion de Desastres (1987). Such a programme includes a very detailed hazard-zone map for flooding and debris flows in the densely inhabited suburbs of Ibagué city (capital of Tolima Department), as well as enquiries about risk knowledge and consciousness among people who live at high risk. We stress the fact that both detailed hazard-zone maps and enquiries should be closely undertaken at the same time, and that distinguishing previous knowledge, existing consciousness and risk perception to forecast the behaviour of people and of the community in case of disaster, are criteria for a better risk assessment.  相似文献   

Comment on “The Moroccan Hercynides” by Hoepffner et al. (Journal of African Earth Sciences, vol. 43, pp. 144–165)     

Martin Roddaz  Jean-Claude Soula  Mohamed Ben Abbou  Stphane Brusset  Pierre Debat  Ahmed Ntarmouchant  Youssef Driouch  Didier Bziat 《Journal of African Earth Sciences》2006,45(4-5):515-517

  相似文献   

Les failles récentes des Grands-Moulins (Savoie) : un Sackung (tassement gravitaire) majeur dans les Alpes françaises     

Jean-Claude Hippolyte  Marc Tardy  Gérard Nicoud 《Comptes Rendus Geoscience》2006,338(10):734-741

In Savoy, the Grands-Moulins recent fault scarps, previously interpreted as seismic fault ruptures, are in fact part of a major Sackung (deep seated gravitational spreading) of the French Alps (9 km long). We mapped more than 60 sackung scarps, some of them reaching 1330 m long and 30 m high. These antislope scarps stop the active screes and offset relict Dryassic rock glaciers by 16 m. We present geomorphologic observations attesting for their gravitational origin. This Sackung is primarily due to glacial debuttressing, while seismic shaking could be a triggering mechanism. To cite this article: J.-C. Hippolyte et al., C. R. Geoscience 338 (2006).  相似文献   

3D Modeling and Kinematics of the External Zone of the French Western Alps (Belledonne and Grand Chatelard Massifs, Maurienne Valley, Savoie)     

Didier Marquer  Philippe Calcagno  Jean-Claude Barfety  Thierry Baudin 《Eclogae Geologicae Helvetiae》2006,99(2):211-222

  相似文献   

How Far Is Too Far? – A Statistical Approach to Context‐contingent Proximity Modeling     

Xiaobai Yao  Jean-Claude Thill 《Transactions in GIS》2005,9(2):157-178

Proximity is a fundamental concept in any comprehensive ontology of space ( Worboys 2001 ). The provision of a context‐contingent translation mechanism between linguistic proximity measures (e.g. “near”, “far”) and metric distance measures is an important topic in current GIS research. After a discussion of context factors that mediate the relationship between linguistic and metric distance measures, we present a statistical approach, Ordered Logit Regression, to the context‐contingent proximity modeling. The approach can predict proximity given the corresponding metric distance and context variables. An empirical case study with human subjects is carried out using this statistical approach. Interpretation and predictive accuracy of the empirical case study are discussed.  相似文献   

Experimental study of aluminum speciation in fluoride-rich supercritical fluids   总被引：2，自引：0，他引：2  

Boris TagirovJacques Schott  Jean-Claude HarrichourryStefano Salvi 《Geochimica et cosmochimica acta》2002,66(11):2013-2024

The solubility of the albite-paragonite-quartz mineral assemblage was measured as a function of NaCl and fluorine concentration at 400°C, 500 bars and at 450°C, 500 and 1000 bars. Decreasing Al concentrations with increasing NaCl molality in F-free fluids of low salinity (mNaCl < 0.01) demonstrates that Al(OH)₄⁻ dominates Al speciation and is formed according to the reaction 0.5 NaAl₃Si₃O₁₂H_2(cr)+2 H₂O = 0.5 NaAlSi₃O_8(cr)+Al(OH)₄⁻+H⁺. Log K results for this reaction are −11.28 ± 0.10 and −10.59 ± 0.10 at 400°C, 500 bars and 450°C, 1000 bars, respectively. Upon further salinity increase, Al concentration becomes constant (at 400°C, 500 bars) or even rises (at 450°C, 1000 bars). The observed Al behavior can be explained by the formation of NaAl(OH)₄⁰_(aq) or NaAl(OH)₃Cl_(aq)⁰. The calculated constant for the reaction Al(OH)₄⁻+Na⁺=NaAl(OH)₄⁰_(aq) expressed in log units is equal to 2.46 and 2.04 at 400°C, 500 bars and 450°C, 1000 bars, respectively. These values are in good agreement with the predictions given in Diakonov et al. (1996). Addition of fluoride at m(NaCl) = const = 0.5 caused a sharp increase in Al concentration in equilibrium with the albite-paragonite-quartz mineral assemblage. As fluid pH was also constant, this solubility increase indicates strong aluminum-fluoride complexation with the formation of NaAl(OH)₃F_(aq)⁰ and NaAl(OH)₂F₂⁰_(aq), according to 0.5 NaAl₃Si₃O₁₂H_2(cr)+Na⁺+HF_(aq)⁰+H₂O = 0.5 NaAlSi₃O_8(cr)+ NaAl(OH)₃F_(aq)⁰+H⁺, log K = −5.17 and −5.23 at 400°C and 450°C, 500 bars, respectively, and 0.5 NaAl₃Si₃O₁₂H_2(cr)+Na⁺+2 HF_(aq)⁰ = 0.5 NaAlSi₃O_8(cr)+NaAl(OH)₂F₂⁰_(aq)+H⁺, log K = −2.19 and −1.64 at the same P-T conditions. It was found that temperature increase and pressure decrease promote the formation of Na-Al-OH-F species. Stability of NaAl(OH)₂F₂⁰_(aq) in low-density fluids also increases relative to NaAl(OH)₃F_(aq)⁰. These complexes, together with Al(OH)₂F_(aq)⁰ and AlOHF₂⁰_(aq), whose stability constants were calculated from the corundum solubility measured by Soboleva and Zaraisky (1990) and Zaraisky (1994), are likely to dominate Al speciation in metamorphic fluids containing several ppm of fluorine.  相似文献