Development of a Field Preconcentration/Elution Unit for Routine Determination of Dissolved Metal Concentrations by ICP-OES in Marine Waters: Application for Monitoring of the New Caledonia Lagoon     

Benjamin M. Moreton  Jean-Michel Fernandez  Mathieu B.D. Dolbecq 《Geostandards and Geoanalytical Research》2009,33(2):205-218

An iminodiacetate chelating resin was optimised for the rapid determination of Co, Cu, Fe, Mn and Ni in seawater. Using inexpensive, high-capacity, reusable cartridges allowed high flow rates of up to 25 ml min⁻¹. High preconcentration factors, of up to 500, were obtained in order to analyse samples using an ICP-OES. The requirement for a buffer was eliminated due to the high tolerance of the ICP-OES to interfering matrix elements, thereby further reducing the potential for contamination. Quantification limits in seawater were: Co = 6 ng l⁻¹, Cu = 8 ng l⁻¹, Fe = 6 ng l⁻¹, Mn = 5 ng l⁻¹ and Ni = 6 ng l⁻¹. The method was verified by the analysis of near shore seawater (CASS-4) and open ocean seawater (NASS-5) reference materials. In order to satisfy the high sampling demands using the iminodiacetate cartridges, a portable off-line preconcentration unit was developed for routine analysis. The multi-channel preconcentration unit, was capable of treating up to eight samples simultaneously with concentrating times as little as 30 minutes. The technique was also used to determine dissolved metals in fresh and interstitial waters. The technique has been successfully used in a number of environmental studies and impact assessments to evaluate the effects of mining on the New Caledonian lagoon.  相似文献   

Stepwise palaeoclimate change across the Eocene–Oligocene transition recorded in continental NW Europe by mineralogical assemblages and δ15Norg (Rennes Basin,France)          下载免费PDF全文

Romain Tramoy  Marie Salpin  Johann Schnyder  Alain Person  Mathieu Sebilo  Johan Yans  Véronique Vaury  Jérôme Fozzani  Hugues Bauer 《地学学报》2016,28(3):212-220

The Eocene–Oligocene transition (EOT, ~34 Ma) is the largest global cooling of the Cenozoic Era and led the Earth's climatic system to change from a greenhouse to an icehouse mode. Although it is well documented in marine settings, the few studies focusing on continental environments have demonstrated regional heterogeneities. The study core CDB1, located in the Rennes Basin (Western France), is a unique terrestrial (lacustrine–palustrine) record comprising well‐preserved and terrestrial‐derived organic‐rich sediments encompassing the EOT. Clay minerals and the first organic nitrogen isotope record (δ¹⁵N_org) of terrestrial origin for this period are used to reconstruct palaeoclimate changes across this key interval. As suggested in worldwide marine and a few continental records, a stepwise transition from warm/humid conditions in the Late Eocene to cooler/drier conditions in the Early Oligocene is confirmed in the area. In addition, an episode of drier conditions in the Late Eocene and humid/dry cycles in the Early Oligocene are suggested.  相似文献   

Expression and activity of a multixenobiotic resistance system in the Pacific oyster Crassostrea gigas     

Minier C  Lelong C  Djemel N  Rodet F  Tutundjian R  Favrel P  Mathieu M  Leboulenger F 《Marine environmental research》2002,54(3-5):455-459

The multidrug resistance (MDR) mechanism corresponds to a defence system relying on the expression of high molecular membrane proteins that can actively lower the intracellular concentration of a wide variety of toxins, thus maintaining them below their toxic level. Using RT-PCR, expression levels of a gene belonging to the class I of mammalian mdr genes, has been assessed in different developmental stages of the oyster Crassostrea gigas. While no expression was found in the oocyte or the trocophore stage, a rise of mRNA content was observed from the veliger stage to the juvenile stage, thus indicating the induction of the system as the animal is developing in the environment. The incubation of gill fragments in the dye rhodamine B and subsequent measurements of intracellular fluorescence using a microplate reader indicates that the system can effectively decrease the accumulation of the test compound in a competitive manner with known inhibitors or environmental contaminants as observed in vertebrate cells. The oyster MXR system is thus becoming active in adult oyster and could be of importance in environmentally contaminated areas.  相似文献   

Strategies for waveform processing in sparker data     

Mathieu J. Duchesne  Gilles Bellefleur  Mike Galbraith  Randy Kolesar  Rick Kuzmiski 《Marine Geophysical Researches》2007,28(2):153-164

A sparker is a marine seismic impulsive source used for high-resolution seismic surveys. Sparker sources were very popular during the late 1960s and 1970s before being supplanted by small volume airguns. However, in the last 10 years there has been renewed interest in sparker technology because (1) it can be easily deployed at relatively low costs and (2) in certain areas the use of small airguns is restricted for environmental purposes. In this study a sparker source was used to assess the seismic stratigraphy of Quaternary deposits and to image the sediment/bedrock interface. Three different inverse filtering methods were tested (i.e., spiking deconvolution, match-filtering and vertical seismic profile (VSP) deconvolution) to correct the poor shot-to-shot repeatability of the source and to compress its reverberations. Results show that the matched-filter and VSP deconvolution methods, which design and apply one operator for each shot, produced comparable results, whereas the spiking deconvolution that used the same operator on all traces failed to compress the source signature properly.  相似文献   

Improving MODIS Spatial Resolution for Snow Mapping Using Wavelet Fusion and ARSIS Concept   总被引：1，自引：0，他引：1  

Sirguey  P. Mathieu  R. Arnaud  Y. Khan  M.M. Chanussot  J. 《Geoscience and Remote Sensing Letters, IEEE》2008,5(1):78-82

We propose to fuse the high spatial content of two 250-m spectral bands of the moderate resolution imaging spectroradiometer (MODIS) into its five 500-m bands using wavelet-based multiresolution analysis. Our objective was to test the effectiveness of this technique to increase the accuracy of snow mapping in mountainous environments. To assess the performance of this approach, we took advantage of the simultaneity between the advanced spaceborne thermal emission and reflection radiometer (ASTER) and MODIS sensors. With a 15-m spatial resolution, the ASTER sensor provided reference snow maps, which were then compared to MODIS-derived snow maps. The benefit of the method was assessed through the investigation of various metrics, which showed an improvement from 3% to 20%. Therefore, the enhanced snow map is of great benefit for environmental and hydrological applications in steep terrain.  相似文献   

A complete hydro-climate model chain to investigate the influence of sea surface temperature on recent hydroclimatic variability in subtropical South America (Laguna Mar Chiquita,Argentina)     

Magali Troin  Mathieu Vrac  Myriam Khodri  Daniel Caya  Christine Vallet-Coulomb  Eduardo Piovano  Florence Sylvestre 《Climate Dynamics》2016,46(5-6):1783-1798

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A Geostatistical Definition of Hotspots for Fish Spatial Distributions     

Pierre Petitgas  Mathieu Woillez  Mathieu Doray  Jacques Rivoirard 《Mathematical Geosciences》2016,48(1):65-77

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Thermal‐infrared remote sensing of surface water–groundwater exchanges in a restored anastomosing channel (Upper Rhine River,France)          下载免费PDF全文

David Eschbach  Guillaume Piasny  Laurent Schmitt  Laurent Pfister  Pierre Grussenmeyer  Mathieu Koehl  Grzegorz Skupinski  Abdelaziz Serradj 《水文研究》2017,31(5):1113-1124

Ecohydrological processes are a key element to consider in functional river restorations. In the framework of a LIFE+ European restoration program, we have investigated the potential for airborne thermal‐infrared remote sensing to map surface water–groundwater exchanges and to identify their driving factors. We focused our attention on anastomosing channels on an artificial island of the Upper Rhine River (Rohrschollen), where a new channel was excavated from the floodplain to reconnect an older channel in its upstream part. These hydraulic engineering works led to an increased inflow from the Rhine Canal. Here, we propose an original data treatment chain to (a) georeference the thermal‐infrared images in geographic information system based on visible images, (b) detect and correct data errors, and (c) identify and locate thermal anomalies attributed to groundwater inputs and hyporheic upwellings. Our results, which have been compared to morpho‐sedimentary data, show that groundwater upwelling in the new channel is controlled by riffle–pool sequences and bars. This channel is characterized by large bedload transport and morphodynamic activity, forming riffles and bars. In the old channel, where riffle–pool sequences no longer exist, due to impacts of engineering works and insufficient morphodynamic effects of the restoration, thermal anomalies appeared to be less pronounced. Groundwater inputs seem to be controlled by former gravel bars outcropping on the banks, as well as by local thinning of the low‐permeability clogging layer on the channel bed.  相似文献   

The impact of ENSO on Southern African rainfall in CMIP5 ocean atmosphere coupled climate models     

Bastien Dieppois  Mathieu Rouault  Mark New 《Climate Dynamics》2015,45(9-10):2425-2442

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Changes in large-scale controls of Atlantic tropical cyclone activity with the phases of the Atlantic multidecadal oscillation     

Louis-Philippe Caron  Mathieu Boudreault  Cindy L. Bruyère 《Climate Dynamics》2015,44(7-8):1801-1821

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