Comment on “a test of annual resolution in stalagmites using tree rings”     

Andy Baker  Dominique Genty 《Quaternary Research》2003,59(3):476-478

  相似文献   

A New Method for C ^k -Surface Approximation from a Set of Curves, with Application to Ship Track Data in the Marianas Trench     

Dominique Apprato  Christian Gout  Dimitri Komatitsch 《Mathematical Geology》2002,34(7):831-843

We introduce a surface approximation technique to address the problem of fitting a surface to a given set of curves. The originality of the method lies in its ability to take into account the continuous aspect of the data, and also in the possibility to arbitrarily select the regularity (C⁰, C¹, or higher) of the approximant obtained. We demonstrate the efficiency of the approach by constructing a bathymetry map of the Marianas trench based upon a set of SONAR (SOnic Navigation And Ranging) bathymetry ship track data.  相似文献   

A New Method for C k -Surface Approximation from a Set of Curves,with Application to Ship Track Data in the Marianas Trench     

Apprato  Dominique  Gout  Christian  Komatitsch  Dimitri 《Mathematical Geosciences》2002,34(7):831-843

We introduce a surface approximation technique to address the problem of fitting a surface to a given set of curves. The originality of the method lies in its ability to take into account the continuous aspect of the data, and also in the possibility to arbitrarily select the regularity (C⁰, C¹, or higher) of the approximant obtained. We demonstrate the efficiency of the approach by constructing a bathymetry map of the Marianas trench based upon a set of SONAR (SOnic Navigation And Ranging) bathymetry ship track data.  相似文献   

Distribution d'un élément trace (Cr) dans un sol développé sur roches métamorphiques : variabilité à l'échelle d'un versantDistribution of chromium in soils developed into metamorphic rocks: variability at the hillslope scale     

Sébastien Salvador-Blanes  Sophie Cornu  Dominique King 《Comptes Rendus Geoscience》2002,334(1):51-58

The influence of pedogenetic factors onto spatial variability of chromium in soil surface horizon was studied in a metamorphic area (Massif Central, France) at the hillside scale. A grid survey was performed. Surface soil horizons were sampled at each point and analysed in Cr. Results show the determinant influence of the rock type on Cr content distribution along the slope. However, surface horizons of these soils exhibit a lower Cr content heterogeneity than the deeper horizons. This was explained by soils' material erosion and deposition along the slope. Tillage and hedges also influence the Cr distribution in surface horizon along the slope. To cite this article: S. Salvador-Blanes et al., C. R. Geoscience 334 (2002) 51–58  相似文献   

A geomorphologic kinematic‐wave (GKW) model for estimation of floods from small alpine watersheds     

Dominique D. Brod  Vijay P. Singh  Andre Musy 《水文研究》1999,13(9):1391-1416

A geomorphologic kinematic‐wave (GKW) model was developed for simulation of extreme floods from small alpine catchments. The GKW model couples the kinematic‐wave theory and the geomorphologic representation of the catchment based on the Horton–Strahler ordering scheme. The model was tested on two small alpine catchments in Switzerland, and the agreement between simulated and observed floods was good. Care must however be taken with the computation of slope and roughness parameters. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Pulsed export of carbon in the north-western Mediterranean Sea     

Denis  Michel  Lefevre  Dominique  Thyssen  Melilotus  Jenkinson  Ian R.  Grégori  Gérald 《中国海洋湖沼学报》2023,41(1):189-202

The short term (hourly scale) variability of heterotrophic prokaryote (HP) vertical distribution and respiratory activity, was investigated in the north-western (NW) Mediterranean Sea. HP vertical distribution was determined on board by flow cytometry analysis of seawater samples collected by series of CTD casts. Cell counts and viability were determined for all samples. HP respiratory rates were determined later in the laboratory from filtered seawater samples (23 dm³) from 300–1 150-m depth. The average cell viability was 94.8%±2.2% (n=240). There was no accumulation of dead cells, due to quick decay of damaged cells. In the epipelagic layer, three HP groups were distinguished, two (HNA1, HNA2) whose cells exhibited a high nucleic acid content and one (LNA) with low nucleic acid content cells. HNA2 was most populated at 50 m but not detected at 90 m and below, presumably aerobic anoxygenic photoheterotrophic bacteria (AAPs). The variability in HP abundance was mainly confined in the upper 80 m. A few secondary peaks of HP abundance were observed (80–150 m) in connection with abundance troughs in the surface layer. HP cells were continuously present in a wide layer around 500 m (mean 191×10³ cells/cm³). Below this layer, HP abundance randomly exhibited peaks, coupled to respiratory rate peaks. The HP abundance and variability in the water column was suppressed during a strong wind event. The observed sporadic variability was tentatively interpreted through a pulsed carbon-export mechanism induced by the microorganism production of dissolved polysaccharides, followed by flocculation and rapid sinking. This mechanism would thus contribute to (i) preventing organic matter accumulation in the epipelagic layer, (ii) seeding the water column with live HP cells, and (iii) supplying the aphotic water column with fresh and labile organic matter. This important vertical flux mechanism needs further observations and modelling.

  相似文献   

New Caledonia Ophiolite, Marginal Rifting to Fore-arc Evolution     

Dominique CLUZEL  Jonathan AITCHISON  Arianna SECCHIARI  Alessandra MONTANINI  Delphine BOSCH 《《地质学报》英文版》2020,94(Z1):9-10

  相似文献   

Effects of hydrostatic pressure on microbial alteration of sinking fecal pellets     

Christian Tamburini  Madeleine Goutx  Catherine Guigue  Marc Garel  Dominique Lefvre  Bruno Charrire  Richard Sempr  Stphane Pepa  Michael L. Peterson  Stuart Wakeham  Cindy Lee 《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(18):1533-1546

We used a new experimental device called PASS (PArticle Sinking Simulator) during MedFlux to simulate changes in in situ hydrostatic pressure that particles experience sinking from mesopelagic to bathypelagic depths. Particles, largely fecal pellets, were collected at 200 m using a settling velocity NetTrap (SV NetTrap) in Ligurian Sea in April 2006 and incubated in high-pressure bottles (HPBs) of the PASS system under both atmospheric and continuously increasing pressure conditions, simulating the pressure change experienced at a sinking rate of 200 m d⁻¹. Chemical changes over time were evaluated by measuring particulate organic carbon (POC), carbohydrates, transparent exopolymer particles (TEP), amino acids, lipids, and chloropigments, as well as dissolved organic carbon (DOC) and dissolved carbohydrates. Microbial changes were evaluated microscopically, using diamidinophenylindole (DAPI) stain for total cell counts and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) for phylogenetic distinctions. Concentrations (normalized to POC) of particulate chloropigments, carbohydrates and TEP decreased under both sets of incubation conditions, although less under the increasing pressure regime than under atmospheric conditions. By contrast, dissolved carbohydrates (normalized to DOC) were higher after incubation and significantly higher under atmospheric conditions, suggesting they were produced at the expense of the particulate fraction. POC-normalized particulate wax/steryl esters increased only under pressure, suggesting biochemical responses of prokaryotes to the increasing pressure regime. The prokaryotic community initially consisted of 43% Bacteria, 12% Crenarchaea and 11% Euryarchaea. After incubation, Bacteria dominated (90%) the prokaryote community in all cases, with γ-Proteobacteria comprising the greatest fraction, followed by the Cytophaga–Flavobacter cluster and α-Proteobacteria group. Using the PASS system, we obtained chemical and microbial evidence that degradation by prokaryotes associated with fecal pellets sinking through mesopelagic waters is limited by the increasing pressure they experience.  相似文献   

A model-based evaluation of Marine Protected Areas: the example of eastern Baltic cod (Gadus morhua callarias L.)     

Kraus  Gerd; Pelletier  Dominique; Dubreuil  Julien; Mollmann  Christian; Hinrichsen  Hans-Harald; Bastardie  Francois; Vermard  Youen; Mahevas  Stephanie 《ICES Journal of Marine Science》2009,66(1):109-121

  相似文献   

The planktonic food web of the Bizerte lagoon (south-western Mediterranean) during summer: I. Spatial distribution under different anthropogenic pressures     

Asma Sakka Hlaili  Boutheina Grami  Nathalie Niquil  Michel Gosselin  Dominique Hamel  Marc Troussellier  Hassine Hadj Mabrouk 《Estuarine, Coastal and Shelf Science》2008

The structure and the trophic interactions of the planktonic food web were investigated during summer 2004 in a coastal lagoon of south-western Mediterranean Sea. Biomasses of planktonic components as well as bacterial and phytoplankton production and grazing by microzooplankton were quantified at four stations (MA, MB, MJ and R) inside the lagoon. Station MA was impacted by urban discharge, station MB was influenced by industrial activity, station MJ was located in a shellfish farming sector, while station R represented the lagoon central area. Biomasses and production rates of bacteria (7–33 mg C m⁻³; 17.5–35 mg C m⁻³ d⁻¹) and phytoplankton (80–299 mg C m⁻³; 34–210 mg C m⁻³ d⁻¹) showed high values at station MJ, where substantial concentrations of nutrients (NO₃⁻ and Si(OH)₄) were found. Microphytoplankton, which dominated the total algal biomass and production (>82%), were characterized by the proliferation of several chain-forming diatoms. Microzooplankton was mainly composed of dinoflagellates (Torodinium, Protoperidinium and Dinophysis) and aloricate (Lohmaniellea and Strombidium) and tintinnid (Tintinnopsis, Tintinnus, Favella and Eutintinnus) ciliates. Higher biomass of these protozoa (359 mg C m⁻³) was observed at station MB, where large tintinnids were encountered. Mesozooplankton mainly represented by Calanoida (Acartia, Temora, Calanus, Eucalanus, Paracalanus and Centropages) and Cyclopoida (Oithona) copepods, exhibited higher and lower biomasses at stations MA/MJ and MB, respectively. Bacterivory represented only 35% of bacterial production at stations MB and R, but higher fractions (65–70%) were observed at stations MA and MJ. Small heterotrophic flagellates and aloricate ciliates seemed to be the main controllers of bacteria. Pico- and nanophytoplankton represented a significant alternative carbon pool for micrograzers, which grazing represented 67–90% of pico- and nano-algal production in all stations. Microzooplankton has, however, a relatively low impact on microphytoplankton, as ≤45% of microalgal production was consumed in all stations. This implies that an important fraction of diatom production would be channelled by herbivorous meso-grazers to higher consumers at stations MA and MJ where copepods were numerous. Most of the microalgal production would, however, sink particularly at station MB where copepods were scare. These different trophic interactions suggest different food web structures between stations. A multivorous food web seemed to prevail in stations MJ and MA, whereas microbial web was dominant in the other stations.  相似文献