Scale-dependent habitat use by a large free-ranging predator,the Mediterranean fin whale     

Cédric Cotté  Christophe Guinet  Isabelle Taupier-Letage  Bruce Mate  Estelle Petiau 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(5):801-811

Since the heterogeneity of oceanographic conditions drives abundance, distribution, and availability of prey, it is essential to understand how foraging predators interact with their dynamic environment at various spatial and temporal scales. We examined the spatio-temporal relationships between oceanographic features and abundance of fin whales (Balaenoptera physalus), the largest free-ranging predator in the Western Mediterranean Sea (WM), through two independent approaches. First, spatial modeling was used to estimate whale density, using waiting distance (the distance between detections) for fin whales along ferry routes across the WM, in relation to remotely sensed oceanographic parameters. At a large scale (basin and year), fin whales exhibited fidelity to the northern WM with a summer-aggregated and winter-dispersed pattern. At mesoscale (20–100 km), whales were found in colder, saltier (from an on-board system) and dynamic areas defined by steep altimetric and temperature gradients. Second, using an independent fin whale satellite tracking dataset, we showed that tracked whales were effectively preferentially located in favorable habitats, i.e. in areas of high predicted densities as identified by our previous model using oceanographic data contemporaneous to the tracking period. We suggest that the large-scale fidelity corresponds to temporally and spatially predictable habitat of whale favorite prey, the northern krill (Meganyctiphanes norvegica), while mesoscale relationships are likely to identify areas of high prey concentration and availability.  相似文献   

Dust Formation Chemistry in Carbon-Rich Wolf-Rayet Winds     

Yoann H. Le Teuff  Isabelle Cherchneff 《Astrophysics and Space Science》1997,251(1-2):389-392

Dust formation processes are investigated in the hot hydrogen-deficient wind of carbon-rich Wolf-Rayet (WC) stars. Results show that dust precursors (small linear carbon chains) form in large quantities only at high gas densities. This suggests that a clumpy wind or an equatorial disc are necessary to trigger dust formation in WC stars. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

Contrasting conditions preceding MIS3 and MIS2 Heinrich events   总被引：2，自引：0，他引：2  

Elsa Jullien  Francis E. Grousset  Sidney R. Hemming  Victoria L. Peck  Ian R. Hall  Cdric Jeantet  Isabelle Billy 《Global and Planetary Change》2006,54(3-4):225-238

This paper presents an integrated multi-tracer study performed on piston cores recovered in the glacial ice-rafted detritus belt, stretching from Newfoundland to the Irish margin across the North Atlantic (40–55°N), in order to compare in detail the internal structure of each Heinrich event (HE). These tracers are IRD counts (quartz, dolomite, volcanic grains), their Nd isotopic composition and Ar–Ar datings of individual hornblende grains. A focus on the detailed structure of HE confirms that all intervals of massive sediment flux, specifically Heinrich layers HL1-to-5 (HLs), were dominated by North American, Laurentide ice-sheet surges from Hudson Strait, that are evident as far east as the Bay of Biscay (European margin). The sequences of events leading up to the HLs, however, present significant dissimilarities. One important difference is that HL2 and HL1 were preceded by “precursor events” (increases in the number of lithic grains per gram from non-Laurentide sediment sources). Sediment debris derived from near-simultaneous iceberg releases originating from the European ice-sheet are only detectable close to the European margin. In contrast there are no comparable precursor events before HL5 and HL4. This observation implies that precursor events are unlikely to be mechanistically linked to the triggering of HEs. The similarity of the HLs, against contrasting background conditions, is a significant observation that should add constraints to their origin.  相似文献   

Evaluation of sulfate reduction at experimentally induced mixing interfaces using small-scale push–pull tests in an aquifer–wetland system     

Tara A. Kneeshaw  Jennifer T. McGuire  Erik W. Smith  Isabelle M. Cozzarelli 《Applied Geochemistry》2007,22(12):2618-2629

  相似文献   

Centimeter-scale characterization of biogeochemical gradients at a wetland–aquifer interface using capillary electrophoresis     

Susan Bez-Cazull  Jennifer T. McGuire  Isabelle M. Cozzarelli  Anne Raymond  Lisa Welsh 《Applied Geochemistry》2007,22(12):2664-2683

  相似文献   

Estimating Sensible and Latent Heat Fluxes over an Inland Water Body Using Optical and Microwave Scintillometers     

Pierre  Adrien  Isabelle  Pierre-Erik  Nadeau  Daniel F.  Thiboult  Antoine  Perelet  Alexei  Rousseau  Alain N.  Anctil  François  Deschamps  Jaril 《Boundary-Layer Meteorology》2022,185(2):277-308

Boundary-Layer Meteorology - Observations of turbulent heat fluxes over inland water bodies are scarce despite being critical to adequate lake parametrization for numerical weather forecast and...  相似文献   

Automatic road change detection and GIS updating from high spatial remotely-sensed imagery     

Zhang Qiaoping  Isabelle Couloigner 《地球空间信息科学学报》2013,16(2):89-95

This paper presents a framework for road network change detection in order to update the Canadian National Topographic DataBase (NTDB). The methodology has been developed on the basis of road extraction from IRS-pan images (with a 5.8 m spatial resolution) by using a wavelet approach. The feature matching and conflation techniques are used to road change detection and updating. Elementary experiments have showed that the proposed framework could be used for developing an operational road database updating system.  相似文献   

A model for conductive faults with non-matching grids     

Xavier Tunc  Isabelle Faille  Thierry Gallou?t  Marie Christine Cacas  Pascal Havé 《Computational Geosciences》2012,16(2):277-296

In this paper, we are interested in modeling single-phase flow in a porous medium with known faults seen as interfaces. We mainly focus on how to handle non-matching grids problems arising from rock displacement along the fault. We describe a model that can be extended to multi-phase flow where faults are treated as interfaces. The model is validated in an academic framework and is then extended to 3D non K-orthogonal grids, and a realistic case is presented.  相似文献   

Emerging Contaminants at a Closed and an Operating Landfill in Oklahoma     

William J. Andrews  Jason R. Masoner  Isabelle M. Cozzarelli 《Ground Water Monitoring & Remediation》2012,32(1):120-130

Landfills are the final depositories for a wide range of solid waste from both residential and commercial sources, and therefore have the potential to produce leachate containing many organic compounds found in consumer products such as pharmaceuticals, plasticizers, disinfectants, cleaning agents, fire retardants, flavorings, and preservatives, known as emerging contaminants (ECs). Landfill leachate was sampled from landfill cells of three different age ranges from two landfills in Central Oklahoma. Samples were collected from an old cell containing solid waste greater than 25 years old, an intermediate age cell with solid waste between 16 and 3 years old, and operating cell with solid waste less than 5 years old to investigate the chemical variability and persistence of selected ECs in landfill leachate of differing age sources. Twenty‐eight of 69 analyzed ECs were detected in one or more samples from the three leachate sources. Detected ECs ranged in concentration from 0.11 to 114 μg/L and included 4 fecal and plant sterols, 13 household\industrial, 7 hydrocarbon, and 4 pesticide compounds. Four ECs were solely detected in the oldest leachate sample, two ECs were solely detected in the intermediate leachate sample, and no ECs were solely detected in the youngest leachate sample. Eleven ECs were commonly detected in all three leachate samples and are an indication of the contents of solid waste deposited over several decades and the relative resistance of some ECs to natural attenuation processes in and near landfills.  相似文献   

Arctic microbial ecosystems and impacts of extreme warming during the International Polar Year     

Warwick F. Vincent  Lyle G. Whyte  Connie Lovejoy  Charles W. Greer  Isabelle Laurion  Curtis A. Suttle  Jacques Corbeil  Derek R. Mueller 《Polar Science》2009,3(3):171-180

As a contribution to the International Polar Year program MERGE (Microbiological and Ecological Responses to Global Environmental change in polar regions), studies were conducted on the terrestrial and aquatic microbial ecosystems of northern Canada (details at: http://www.cen.ulaval.ca/merge/). The habitats included permafrost soils, saline coldwater springs, supraglacial lakes on ice shelves, epishelf lakes in fjords, deep meromictic lakes, and shallow lakes, ponds and streams. Microbiological samples from each habitat were analysed by HPLC pigment assays, light and fluorescence microscopy, and DNA sequencing. The results show a remarkably diverse microflora of viruses, Archaea (including ammonium oxidisers and methanotrophs), Bacteria (including filamentous sulfur-oxidisers in a saline spring and benthic mats of Cyanobacteria in many waterbodies), and protists (including microbial eukaryotes in snowbanks and ciliates in ice-dammed lakes). In summer 2008, we recorded extreme warming at Ward Hunt Island and vicinity, the northern limit of the Canadian high Arctic, with air temperatures up to 20.5 °C. This was accompanied by pronounced changes in microbial habitats: deepening of the permafrost active layer; loss of perennial lake ice and sea ice; loss of ice-dammed freshwater lakes; and 23% loss of total ice shelf area, including complete break-up and loss of the Markham Ice Shelf cryo-ecosystem. These observations underscore the vulnerability of Arctic microbial ecosystems to ongoing climate change.  相似文献