Search results for "Deposit"
showing 10 items of 1447 documents
Overview paper: New insights into aerosol and climate in the Arctic
2019
Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013. (1) Unexpectedly high summer…
Convective hydration in the tropical tropopause layer during the StratoClim aircraft campaign: pathway of an observed hydration patch
2018
The source and pathway of the hydration patch in the TTL (tropical tropopause layer) that was measured during the Stratospheric and upper tropospheric processes for better climate predictions (StratoClim) field campaign during the Asian summer monsoon in 2017 and its connection to convective overshoots are investigated. During flight no. 7, two remarkable layers are measured in the TTL, namely (1) the moist layer (ML) with a water vapour content of 4.8–5.7 ppmv in altitudes of 18–19 km in the lower stratosphere and (2) the ice layer (IL) with ice content up to 1.9 eq. ppmv (equivalent parts per million by volume) in altitudes of 17–18 km in the upper tropo…
On the use of geophysical methods to characterize heterogeneities of quaternary alluvial deposits. Application to stormwater infiltration.
2007
Colloque avec actes et comité de lecture. International.; International audience; Stormwater infiltration basins are generally built on geological formations with large values of hydraulic conductivity. Such is the case for quaternary alluvial formations, among which are glaciofluvial deposits. Two geophysical investigation methods, namely ground-penetrating radar and electrical tomography, were tested on an infiltration basin built on a glaciofluvial deposit. Geophysical profiles were calibrated on a trench wall dug in the glaciofluvial formation. A sedimentological study coupled to geophysical measurements behind the trench wall highlights the three-dimensional architecture of the deposit…
Mollusc shellomes: Past, present and future.
2020
13 pages; International audience; In molluscs, the shell fabrication requires a large array of secreted macromolecules including proteins and polysaccharides. Some of them are occluded in the shell during mineralization process and constitute the shell repertoire. The protein moieties, also called shell proteomes or, more simply, 'shellomes', are nowadays analyzed via high-throughput approaches. These latter, applied so far on about thirty genera, have evidenced the huge diversity of shellomes from model to model. They also pinpoint the recurrent presence of functional domains of diverse natures. Shell proteins are not only involved in guiding the mineral deposition, but also in enzymatic a…
Early Triassic proliferation of microbial deposit
2019
International audience; In modern examples of well-developed microbial-dominated deposits associated with metazoan organisms can be currently found in various environments including but not restricted to lagoons in Polynesia (Sprachta et al., 2001), the warm water of the Cuba (e.g., Bouton et al., 2016; Pace et al., 2018), the hypersaline lakes of the Great Salt Lake (USA; e.g., Bouton et al., 2016; Vennin et al., 2019; Vanden Berg, 2019), or the alkaline Satonda Crater Lake in Indonesia (Arp et al., 2003; Satuyana et al., 2010). In Early Triassic, several authors indicated that microbial deposits are frequently associated with sponges, bivalves, brachiopods, ostracods and echinoderms and d…
The transport history of two Saharan dust events archived in an Alpine ice core
2005
Mineral dust from the Saharan desert can be transported across the Mediterranean towards the Alpine region several times a year. When coinciding with snowfall, the dust can be deposited on Alpine glaciers and then appears as yellow or red layers in ice cores. Two such significant dust events were identified in an ice core drilled at the high-accumulation site Piz Zupó in the Swiss Alps (46°22' N, 9°55' E, 3850 m a.s.l.). From stable oxygen isotopes and major ion concentrations, the events were approximately dated as October and March 2000. In order to link the dust record in the ice core to the meteorological situation that led to the dust events, a novel methodology based on b…
Hirnantian glacial and deglacial record in SW Djado Basin (NE Niger).
2007
Pluridisciplinary fieldwork highlights features generated by an extended ice-sheet in the Djado Basin during the Hirnantian. Two glacial palaeovalley systems associated with glacial pavements and separated by thin glaciomarine interstadial series are revealed. Rigid glacial pavements characterised by abrasion erosion are differentiated from soft glacial pavements characterised by soft-bed deformation. Glacial pavements are associated with subglacial bedforms such as megaflutes, flutes and meltwater channels. They are also associated with clastic dykes and glaciotectonic structures such as deformed flutes, subglacial folds and duplex structures. This record demonstrates that ice was warm-bas…
Origin and diversity of testate amoebae shell composition: Example of Bullinularia indica living in Sphagnum capillifolium
2017
Testate amoebae are free-living shelled protists that build a wide range of shells with various sizes, shapes, and compositions. Recent studies showed that xenosomic testate amoebae shells could be indicators of atmospheric particulate matter (PM) deposition. However, no study has yet been conducted to assess the intra-specific mineral, organic, and biologic grain diversity of a single xenosomic species in a natural undisturbed environment. This study aims at providing new information about grain selection to develop the potential use of xenosomic testate amoebae shells as bioindicators of the multiple-origin mineral/organic diversity of their proximal environment. To fulfil these objective…
Characterisation and distribution of deposited trace elements transported over long and intermediate distances in north-eastern France using Sphagnum…
2015
Abstract Trace elements in the form of particulate matter can be transported downwind from their emission sources and may have negative effects on human health and ecosystems. The transport of trace elements is often studied by monitoring their accumulation in mosses. The aim of this study was to characterise and describe the distribution of deposited trace elements transported over long and intermediate distances in north-eastern France, a location far from the main emission sources. We analysed the trace element accumulation in Sphagnum capillifolium in 54 ombrotrophic peatlands distributed in six regions of France (Alps, Jura, Massif Central, Morvan, Rhone corridor and Vosges). The conce…
Microbial ecology of the rhizosphere
2006
Part II. Selected MethodsPlant-microbe Chapitre 9 : Interactions and Soil Quality; International audience