Origin and fluxes of atmospheric REE entering an ombrotrophic peat bog in Black Forest (SW Germany): Evidence from snow, lichens and mosses

The fate of the Rare Earth Elements (REE) were investigated in different types of archives of atmospheric deposition in the Black Forest, Southern Germany: (1) a 70 cm snow pack collected on the domed part of a raised bog and representing 2 months of snow accumulation, (2) a snow sample collected close to the road about 500 m from the peat bog, (3) two species of lichens and (4) a peat profile representing 400 years of peat accumulation as well as a “preanthropogenic” sample and the living moss layer from the top of the core. REE concentrations in peat are significantly correlated to Ti which is a lithogenic conservative element suggesting that REE are immobile in peat bog environments. Snow, lichens and peat samples show similar PAAS (Post Archean Australian Shale) normalized REE distributions suggesting that the complete atmospheric REE signal is preserved in the peat profile. However, the annual flux of REE accumulated by the peat is ca. 10 times greater than that of the bulk winter flux of REE. This difference probably indicates that the REE concentrations in the snowpack are not representative of the average REE flux over the whole year. Despite the pronounced geological differences between this site (granite host-rock) and a previously studied peat bog in Switzerland (limestone host-rock) similar REE distribution patterns and accumulation rates were found at both sites. Given that both sites confirm an Upper Continental Crust signature, the data suggests both sites are influenced by regional and not local, soil-derived lithogenic aerosols

Recent atmospheric Pb deposition at a rural site in southern Germany assessed using a peat core and snowpack, and comparison with other archives

In a peat bog from Black Forest, Southern Germany, the rate of atmospheric Pb accumulation was quantified using a peat core dated by 210Pb and 14C. The most recent Pb accumulation rate (2.5 mg m−2 y−1) is similar to that obtained from a snowpack on the bog surface, which was sampled during the winter 2002 (1 to 4 mg m−2 y−1). The Pb accumulation rates recorded by the peat during the last 25 yr are also in agreement with published values of direct atmospheric fluxes in Black Forest. These values are 50 to 200 times greater than the “natural” average background rate of atmospheric Pb accumulation (20 μg m−2 y−1) obtained using peat samples from the same bog dating from 3300 to 1300 cal. yr B.C. The isotopic composition of Pb was measured in both the modern and ancient peat samples as well as in the snow samples, and clearly shows that recent inputs are dominated by anthropogenic Pb. The chronology and isotopic composition of atmospheric Pb accumulation recorded by the peat from the Black Forest is similar to the chronologies reported earlier using peat cores from various peat bogs as well as herbarium samples of Sphagnum and point to a common Pb source to the region for the past 150 years. In contrast, Pb contamination occurring before 1850 in southwestern Germany, differs from the record published for Switzerland mainly due to the mining activity in Black Forest. Taken together, the results show that peat cores from ombrotrophic bogs can yield accurate records of atmospheric Pb deposition, provided that the cores are carefully collected, handled, prepared, and analysed using appropriate methods

Comment on “The biosphere: A homogeniser of Pb-isotope signals” by C. Reimann, B. Flem, A. Arnoldussen, P. Englmaier, T.E. Finne, F. Koller and Ø. Nordgulen

Reimann et al. (2008) recently published a study on Pb-isotope signature along a 120 km long transect cutting the city of Oslo. Based on concentration but also isotope data, they misinterpret Pb concentration of the biosphere in rural places and explain these large enrichments of Pb as being due to natural processes. The study ignores numerous previous studies either on local, regional or global scales (see reviews by Shotyk and Le Roux, 2005 and Callender, 2003, and references therein), which clearly demonstrate that anthropogenic Pb emitted in the atmosphere from different sources (leaded gasoline, coal burning, metallurgy, etc.) was and is dispersed worldwide. The study also ignores work on Norway by the Steinnes and colleagues group (Harmens et al., 2008, Steinnes et al., 2005a, Steinnes et al., 2005b and Åberg et al., 2004), and measurements and modelling by the EMEP network (www.emep.int/, EMEP, 2005). The study also neglects numerous works on preanthropogenic Pb deposition rate and isotopic signature using continental archives of atmospheric deposition like peat bogs (Shotyk et al., 1998, Klaminder et al., 2003, Kylander et al., 2005 and Le Roux et al., 2005). These studies have shown that preanthropogenic Pb atmospheric deposition rate and its Pb isotopic signature is regionally defined, but also that those signals are negligible compared to past 2 ka and recent Pb atmospheric fluxes (Table 1)

Numerical model validation for mooring systems: Method and application for wave energy converters

Copyright © 2015 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Renewable Energy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Renewable Energy Vol. 75 (2015), DOI: 10.1016/j.renene.2014.10.063The design of wave energy mooring systems is challenging: overdesign incurs a significant cost penalty, underdesign may lead to a premature failure and incorrect design could reduce the power production. Consequently, compliant mooring systems are being developed for wave energy applications. This paper presents tank test results for a scale model of the buoy and mooring used at the South West Mooring Test Facility (SWMTF), an offshore facility developed to conduct long-term sea trials for wave energy device moorings. A compliant three leg catenary mooring system using Nylon ropes in the water column is investigated. Preliminary static, quasi-static, decay, regular and irregular wave tests were conducted on the 1:5 scale model, using the Ifremer basin in Brest. A corresponding numerical model was developed with a time-domain mooring modelling tool, inputting hydrodynamic data from a radiation/diffraction potential modelling program. After the calibration of several hydrodynamic parameters, the numerical model demonstrated good agreement with the experiment. However, numerical results show large differences with the field test results, mainly because of unknowns in the anchor position. The methods and procedures presented will allow the effective validation of numerical models to enable the development of appropriate mooring systems in wave energy applications.MERiFICMARINETPRIMaR

Compte-rendu des journées internationales de l’analyse secondaire en recherche qualitative

Report on the International Symposium: Secondary Analysis in Qualitative Research. Utopia and Perspective?:Qualitative secondary analysis is a new field of research in France. A symposium on this issue was organized by the group CAPAS and held in Grenoble (MSH-Alpes) on the 3rd and 4th of November 2005. The following issues were discussed: state of the art in qualitative research with interviews in social and human sciences; Anglo-Saxon and French practices of secondary analysis; ethical, legal and methodological questions regarding archiving and secondary analysis of interviews; epistemological questions.L’analyse secondaire du qualitatif est un nouveau domaine de recherche en France. Deux Journées Internationales organisées par le groupe CAPAS ont porté sur ce domaine. Elles ont eu lieu le 3 et le 4 novembre 2005 à Grenoble (MSH-Alpes). Les objectifs de cette manifestation étaient les suivants : faire un état de lieu de la recherche qualitative à entretiens dans les sciences humaines et sociales ; présenter l’usage de l’analyse secondaire dans le monde anglo-saxon et en France ; aborder des questions déontologiques, juridiques et méthodologiques liées à la capitalisation des entretiens et à leur analyse secondaire ; ouvrir sur des prospectives épistémologiques

The Search Coil Magnetometer for THEMIS

International audienceTHEMIS instruments incorporate a tri-axial Search Coil Magnetometer (SCM) designed to measure the magnetic components of waves associated with substorm breakup and expansion. The three search coil antennas cover the same frequency bandwidth, from 0.1 Hz to 4 kHz, in the ULF/ELF frequency range. They extend, with appropriate Noise Equivalent Magnetic Induction (NEMI) and sufficient overlap, the measurements of the fluxgate magnetometers. The NEMI of the searchcoil antennas and associated pre-amplifiers is smaller than 0.76 pT/ p Hz at 10 Hz.The analog signals produced by the searchcoils and associated preamplifiers are digitized and processed inside the IDPU, together with data from the EFI instrument. Searchcoil telemetry includes waveform transmission, FFT processed data, and data from a filter bank. The frequency range covered in waveform depends on the available telemetry. The searchcoils and their three axis structures have been precisely calibrated in a quiet site, and the calibration of the transfer function is checked on board usually once per orbit. The tri-axial searchcoils implemented on the five THEMIS spacecraft are working nominally

Incision ante- et post-capture dans les vallées de l’Ornainet de la Saulx (Est du bassin de Paris)

Les travaux de cartographie montrent que les formations alluviales et les paléoformes fluviatiles des vallées de l’Ornain et de la Saulx permettent de reconstituer 11 stades de creusement plio-pléistocène regroupés en 4 épisodes : A, très ancien ; B, ancien ; C, récent ; D, actuel. Deux d’entre eux (A, B) sont antérieurs à la capture de l’Ornain et de la Saulx par la Marne et les deux autres (C, D) lui sont postérieurs. Les alluvions anté-capture, bien conservées, ont été rattachées au Quaternaire moyen d’après la faune et l’industrie préhistorique. Les taux d’incision de la Saulx et de l’Ornain ont brusquement varié suite à leur capture par la Marne, événement survenu il y a environ 250 ka BP. Estimées à environ  3 à 4 cm/ka sur tout le secteur (dans le Paléo-Perthois comme dans le Barrois) pour la période anté-capture, les vitesses d’incision sont nettement plus élevées pour la période post-capture. Maximales (12 à 20 cm/ka) sur le site de capture, elles se réduisent progressivement d’aval en amont (8 à 10 cm/ka à Stainville et4 à 6 cm/ka à Tréveray) et varient dans le détail en fonction des conditions liées à la nature du substratum, aux confluences et aux processus karstiques.Mapping shows that the alluvial formations and fluvial palaeoforms of the Ornain and Saulx valleys can be used to reconstruct 11 stages of Plio-Pleistocene incision subdivided in to 4 episodes : A, very old ;B, old ; C, recent ; D, present. Two of them (A, B) predate the capture of the Ornain and the Saulx by the Marne, and the two others (C, D) post-date it. The well-preserved pre-capture alluvial deposits were linked to the Mid-Quaternary by the fauna and prehistoric industry. The rates of incision of the Saulx and the Ornain varied abruptly following their capture by the Marne, an event which occurred about 250 ka BP. Estimated at about 3 to 4 cm/ka throughout the sector (in the Paleo-Perthois and the Barrois) for the pre-capture period, incision speed increased considerably during the post-capture period. Maximum rates (12 to 20 cm/ka) were recorded at the capture site and gradually decreased upstream (8 to 10 cm/ka at Stainville and 4 to 6 cm/ka at Tréveray), varying in detail according to conditions linked to the nature of the substrate, confluences and karstic processes.Auf der Grundlage der in diesem Rahmen vorgenommenen Kartografier­ arbeiten lassen sich in den alluvialen Formationen und fluviatilen Paläo-Formen der Täler des Ornain und der Saulx 11 Einschnittstadien des Plio-Pleistozäns rekonstituieren, die sich wiederum in vier Abschnitte : A, sehr alt ; B, alt ; C, jung ; D, gegenwärtig, unterteilen. Zwei von ihnen (A, B) sind vor der Anzapfung des Ornain und der Saulx durch die Marne und die beiden anderen (C, D) danach anzusiedeln. Die gut konservierten Ablagerungen aus der Zeit vor der Anzapfung wurden entsprechend der Fauna und der prähistorischen Industrie dem mittleren Quartär zugeordnet. Die Einschnittwerte der Saulx und des Ornain haben sich infolge ihrer Anzapfung durch die Marne, der vor etwa 250 ka BP erfolgte, erheblich geändert. Sie werden für die Periode vor der Anzapfung und für den gesamten Bereich (im Paläo-Perthois als auch im Barrois) auf 3-4 cm/ka geschätzt. In der Periode nach der Anzapfung sind die Einschnittswerte deutlich höher. Die Höchstwerte (12-20 cm/ka) am Ort der Anzapfung nehmen Richtung flussaufwärts ab (8-10 cm/ka in Stainville und 4-6 cm/ka in Tréveray) und variieren im einzelnen in Abhängigkeit von der Art des Untergrundes sowie der Zuflüsse und der Karsteinwirkungen

Incision ante- et post-capture dans les vallées de l’Ornainet de la Saulx (Est du bassin de Paris)

Les travaux de cartographie montrent que les formations alluviales et les paléoformes fluviatiles des vallées de l’Ornain et de la Saulx permettent de reconstituer 11 stades de creusement plio-pléistocène regroupés en 4 épisodes : A, très ancien ; B, ancien ; C, récent ; D, actuel. Deux d’entre eux (A, B) sont antérieurs à la capture de l’Ornain et de la Saulx par la Marne et les deux autres (C, D) lui sont postérieurs. Les alluvions anté-capture, bien conservées, ont été rattachées au Quaternaire moyen d’après la faune et l’industrie préhistorique. Les taux d’incision de la Saulx et de l’Ornain ont brusquement varié suite à leur capture par la Marne, événement survenu il y a environ 250 ka BP. Estimées à environ  3 à 4 cm/ka sur tout le secteur (dans le Paléo-Perthois comme dans le Barrois) pour la période anté-capture, les vitesses d’incision sont nettement plus élevées pour la période post-capture. Maximales (12 à 20 cm/ka) sur le site de capture, elles se réduisent progressivement d’aval en amont (8 à 10 cm/ka à Stainville et4 à 6 cm/ka à Tréveray) et varient dans le détail en fonction des conditions liées à la nature du substratum, aux confluences et aux processus karstiques.Mapping shows that the alluvial formations and fluvial palaeoforms of the Ornain and Saulx valleys can be used to reconstruct 11 stages of Plio-Pleistocene incision subdivided in to 4 episodes : A, very old ;B, old ; C, recent ; D, present. Two of them (A, B) predate the capture of the Ornain and the Saulx by the Marne, and the two others (C, D) post-date it. The well-preserved pre-capture alluvial deposits were linked to the Mid-Quaternary by the fauna and prehistoric industry. The rates of incision of the Saulx and the Ornain varied abruptly following their capture by the Marne, an event which occurred about 250 ka BP. Estimated at about 3 to 4 cm/ka throughout the sector (in the Paleo-Perthois and the Barrois) for the pre-capture period, incision speed increased considerably during the post-capture period. Maximum rates (12 to 20 cm/ka) were recorded at the capture site and gradually decreased upstream (8 to 10 cm/ka at Stainville and 4 to 6 cm/ka at Tréveray), varying in detail according to conditions linked to the nature of the substrate, confluences and karstic processes.Auf der Grundlage der in diesem Rahmen vorgenommenen Kartografier­ arbeiten lassen sich in den alluvialen Formationen und fluviatilen Paläo-Formen der Täler des Ornain und der Saulx 11 Einschnittstadien des Plio-Pleistozäns rekonstituieren, die sich wiederum in vier Abschnitte : A, sehr alt ; B, alt ; C, jung ; D, gegenwärtig, unterteilen. Zwei von ihnen (A, B) sind vor der Anzapfung des Ornain und der Saulx durch die Marne und die beiden anderen (C, D) danach anzusiedeln. Die gut konservierten Ablagerungen aus der Zeit vor der Anzapfung wurden entsprechend der Fauna und der prähistorischen Industrie dem mittleren Quartär zugeordnet. Die Einschnittwerte der Saulx und des Ornain haben sich infolge ihrer Anzapfung durch die Marne, der vor etwa 250 ka BP erfolgte, erheblich geändert. Sie werden für die Periode vor der Anzapfung und für den gesamten Bereich (im Paläo-Perthois als auch im Barrois) auf 3-4 cm/ka geschätzt. In der Periode nach der Anzapfung sind die Einschnittswerte deutlich höher. Die Höchstwerte (12-20 cm/ka) am Ort der Anzapfung nehmen Richtung flussaufwärts ab (8-10 cm/ka in Stainville und 4-6 cm/ka in Tréveray) und variieren im einzelnen in Abhängigkeit von der Art des Untergrundes sowie der Zuflüsse und der Karsteinwirkungen