|
|
Boulinier, T. , Gamble, A., Tornos, J. & Garnier, R. (2017). Circulation d'agents infectieux dans les populations de vertébrés coloniaux des terres australes: surveillance, compréhension et implications pour la gestion.
Abstract: The objectives of program ECOPATH 1151 relate to the circulation of infectious agents in vertebrate populations of southern polar areas. Eco-epidemiological dynamics are studied by combining different approaches, from field observations and experiments to laboratory analyses and modeling. The questions have basic and applied implications, from the evolution of the immune system to the control of deleterious infectious diseases threatening wild populations. Within Amsterdam Island, where recurrent massive die-offs of nestlings of the yellow-nosed albatross have been recorded, a vaccine is tested and the role of the local breeding species in disease maintenance is explored. Scavenging and predatory subantarctic skuas prove highly exposed to the agent of avian cholera and their movements and interactions with rats are likely to contribute to disease spread. At larger scales, research is notably focused on dispersal of tick-borne disease agents. Consequences for setting up disease surveillance programs are also explored.
Programme: 1151
|
|
|
|
Lamarque, G., Bascou, J., Ménot, R.P., Paquette, J.L., Rolland, Y., Cottin, J.Y. (2015). George V Land paragneisses xenoliths dating. New insights for the Antarctica-Australia connection and geodynamic reconstructions.
|
|
|
|
Lamarque, G., Bascou, J., Maurice, C., Cottin, J.Y., Ménot, R.P. (2016). Deformation processes at the Archean-Proteozoic transition. Microstructural study of the Mertz shear zone, East Antarctica.
|
|
|
|
Gaëlle Lamarque, Jérôme Bascou, Claire Maurice, Jean-Yves Cottin, Nicolas Riel, René-Pierre Ménot. (2016). Microstructures, deformation mechanisms and seismic properties of a Palaeoproterozoic shear zone: The Mertz shear zone, East-Antarctica (Vol. 680).
Abstract: The Mertz shear zone (MSZ) is a lithospheric scale structure that recorded mid-crustal deformation during the 1.7Ga orogeny. We performed a microstructural and crystallographic preferred orientation (CPO) study of samples from both mylonites and tectonic boudins that constitute relics of the Terre Adélie Craton (TAC). The deformation is highly accommodated in the MSZ by anastomosed shear bands, which become more scattered elsewhere in the TAC. Most of the MSZ amphibolite-facies mylonites display similar CPO, thermal conditions, intensity of deformation and dominant shear strain. Preserved granulite-facies boudins show both coaxial and non-coaxial strains related to the previous 2.45Ga event. This former deformation is more penetrative and less localized and shows a deformation gradient, later affected by a major phase of recrystallization during retrogression at 2.42Ga. Both MSZ samples and granulite-facies tectonic boudins present microstructures that reflect a variety of deformation mechanisms associated with the rock creep that induce contrasted CPO of minerals (quartz, feldspar, biotite, amphibole and orthopyroxene). In particular, we highlight the development of an “uncommon” CPO in orthopyroxene from weakly deformed samples characterized by (010)-planes oriented parallel to the foliation plane, [001]-axes parallel to the stretching lineation and clustering of [100]-axes near the Y structural direction. Lastly, we computed the seismic properties of the amphibolite and granulite facies rocks in the MSZ area in order to evaluate the contribution of the deformed intermediate and lower continental crust to the seismic anisotropy recorded above the MSZ. Our results reveal that (i) the low content of amphibole and biotite in the rock formations of the TAC, and (ii) the interactions between the CPO of the different mineralogical phases, generate a seismically isotropic crust. Thus, the seismic anisotropy recorded by the seismic stations of the TAC, including the MSZ, must be due to mantle rather than crustal structures.
Keywords: Crustal deformation Crystallographic preferred orientation (CPO) East Antarctica Microstructures Shear zone Strain localization
Programme: 1003
|
|
|
|
Mourier, T. (2017). Structure magnétique du crtaon de Terre Adélie (Antarctique Est).
|
|
|
|
Gaston Godard, Julien Reynes, Jérôme Bascou, René-Pierre Ménot, Rosaria Palmeri. (2017). First rocks sampled in Antarctica (1840): Insights into the landing area and the Terre Adélie craton (Vol. 349).
Abstract: In January 1840, Dumont d’Urville's expedition landed along the coast of “Terre Adélie” and took three rock specimens, the first ever sampled on the Antarctic continent. The petrological and geochemical study of these samples, stored at the “Muséum national d’histoire naturelle”, in Paris, characterizes them as migmatitic cordierite+microcline-bearing paragneiss and mesocratic quartz+biotite-bearing amphibolite. The paragneiss reached 670°C at 3.2 kbar, suggesting an abnormal high-T gradient of ca. 60°C/km during the regional metamorphism that affected the “Terre Adélie” craton 1.7Ga ago. The studied samples are identical to the rocks observed at the “Rocher du Débarquement”, confirming that this was the actual landing place. On the other hand, quartz diorite and volcanic rocks reportedly sampled in Adélie Land during the same expedition and stored at Le Mans and Toulouse Museums do not originate from Antarctica. The examination of Dumont d’Urville's map suggests an icecap shrinking by 9 km in the landing area since 1840.
Keywords: “Terre Adélie” craton Antarctica High- metamorphism Icecap shrinking Little Ice age Migmatite Prehnite-pumpellyite
Programme: 1003
|
|
|
|
L. T. Ellis, M. Alataş, M. Aleffi, A. Alegro, V. Šegota, S. Ozimec, N. Vuković, N. Koletić, D. Prlić, M. Bontek, A. K. Asthana, D. Gupta, V. Sahu, K. K. Rawat, V. A. Bakalin, K. G. Klimova, K. Baráth, L. N. Beldiman, J. Csiky, J. Deme, D. Kovács, M. J. Cano, J. Guerra, I. V. Czernyadjeva, M. V. Dulin, P. Erzberger, T. Ezer, V. E. Fedosov, S. Fontinha, M. Sim-Sim, C. A. Garcia, A. Martins, I. Granzow-de la Cerda, L. Sáez, K. Hassel, H. Weibull, N. G. Hodgetts, M. Infante, P. Heras, T. Kiebacher, J. Kučera, M. Lebouvier, R. Ochyra, M. Ören, B. Papp, S. J. Park, B.-Y. Sun, V. Plášek, S. Poponessi, R. Venanzoni, D. Purger, F. Reis, M. Sinigla, A. Stebel, S. Ştefănuţ, G. Uyar, G. Vončina, M. J. Wigginton, K.-T. Yong, M. S. Chan, Y.-J. Yoon. (2017). New national and regional bryophyte records, 52 (Vol. 39).
|
|
|
|
Damien Ertz, Roar S. Poulsen, Maryvonne Charrier, Ulrik Søchting. (2017). Taxonomy and phylogeny of the genus Steinera (Arctomiales, Arctomiaceae) in the subantarctic islands of Crozet and Kerguelen (Vol. 324).
Abstract: The lichenized genus Steinera is revised for the archipelagos of Crozet and of Kerguelen, with a high level of endemism revealed. It is shown to represent a good example of convergent evolution between two different orders. Phylogenetic analyses using nuLSU, RPB1 and mtSSU sequences show that two different species groups can be recognized: Steinera s. str. belongs to the Arctomiaceae (Arctomiales) and is characterized notably by species having pluriseptate ascospores, and a second species group belongs to the Koerberiaceae (Peltigerales) and is characterized notably by simple ascospores sometimes having a plasma-bridge. The genus Henssenia is newly described to accommodate this latter group. The type species of Steinera is shown to have been erroneously treated in the past, with Steinera molybdoplaca being the type of Steinera and “S.” glaucella belonging to the genus Henssenia. A sorediate morph is recorded for S. molybdoplaca and the results confirmed using a 4-gene phylogeny, including nuITS sequences. Some species previously described in the genera Arctomia and Massalongia from the Southern Hemisphere are shown to belong to Steinera s. str. Five new species are described: Steinera isidiata Ertz & R.S. Poulsen, S. membranacea Ertz & R.S. Poulsen, S. lebouvieri Ertz, S. pannarioides Ertz & R.S. Poulsen and Henssenia subglaucella Ertz & R.S. Poulsen along with seven new combinations: Steinera intricata (Øvstedal) Ertz, S. latispora (Øvstedal) Ertz, S. olechiana (Alstrup & Søchting) Ertz & Søchting, S. subantarctica (Øvstedal) Ertz, Henssenia glaucella (Tuck.) Ertz, R.S. Poulsen & Søchting, H. radiata (P. James & Henssen) Ertz and H. werthii (Zahlbr.) Ertz, R.S. Poulsen & Søchting. An epitype is chosen for Henssenia glaucella and a neotype for H. werthii. “Steinera” symptychia has an isolated phylogenetic position in the Koerberiaceae and might represent a distinct, new genus. World-wide identification keys to the species of Henssenia and Steinera are provided.
Keywords: biodiversity Henssenia Koerberiaceae Lichens Massalongia Peltigerales
Programme: 136
|
|
|
|
Christine Bingen, Charles E. Robert, Kerstin Stebel, Christoph Brühl, Jennifer Schallock, Filip Vanhellemont, Nina Mateshvili, Michael Höpfner, Thomas Trickl, John E. Barnes, Julien Jumelet, Jean-Paul Vernier, Thomas Popp, Gerrit de Leeuw, Simon Pinnock. (2017). Stratospheric aerosol data records for the climate change initiative: Development, validation and application to chemistry-climate modelling (Vol. 203).
Abstract: This paper presents stratospheric aerosol climate records developed in the framework of the Aerosol_cci project, one of the 14 parallel projects from the ESA Climate Change Initiative. These data records were processed from a stratospheric aerosol dataset derived from the GOMOS experiment, using an inversion algorithm optimized for aerosol retrieval, called AerGOM. They provide a suite of aerosol parameters, such as the aerosol extinction coefficient at different wavelengths in the UV–visible range. The extinction record includes the total extinction as well as separate fields for liquid sulfate aerosols and polar stratospheric clouds (PSCs). Several additional fields (PSC flag, etc.) are also provided. The resulting stratospheric aerosol dataset, which spans the whole duration of the GOMOS mission (2002−2012), was validated using different reference datasets (lidar and balloon profiles). In the present paper, the emphasis is put on the extinction records. After a thorough analysis of the original AerGOM dataset, we describe the methodology used to construct the gridded CCI-GOMOS dataset and the resulting improvements on both the AerGOM algorithm and the binning procedure, in terms of spatio-temporal resolution, coverage and data quality. The extinction datasets were validated using lidar profiles from three ground-based stations (Mauna Loa, Garmisch-Partenkirchen, Dumont d'Urville). The median difference of the CCI-GOMOS (Level 3) extinction and ground-based lidar profiles is between ~15% and ~45% in the 16–21km altitude range, depending on the considered site and aerosol type. The CCI-GOMOS dataset was subsequently used, together with a MIPAS SO2 time series, to update a volcanic eruption inventory published previously, thus providing a more comprehensive list of eruptions for the ENVISAT period (2002–2012). The number of quantified eruptions increases from 102 to 230 in the updated inventory. This new inventory was used to simulate the evolution of the global radiative forcing by application of the EMAC chemistry-climate model. Results of this simulation improve the agreement between modelled global radiative forcing of stratospheric aerosols at about 100hPa compared to values estimated from observations. Medium eruptions like the ones of Soufriere Hills/Rabaul (2006), Sarychev (2009) and Nabro (2011) cause a forcing change from about −0.1W/m2 to −0.2W/m2.
Keywords: Aerosol burden Aerosol remote sensing Climate data record Climate modelling ENVISAT GOMOS Lidar Stratospheric aerosol extinction Volcanic eruptions
Programme: 209
|
|
|
|
Jumelet – S. Bekki – P. Keckhut. (2017). Microphysical modelling of volcanic plumes / Comparisons against groundbased and spaceborne lidar data – Colloque Volcanique – SGF – Janvier 2017.
Abstract: We present a high-resolution isentropic microphysical transport model dedicated to stratospheric aerosols and clouds. The model is based on the MIMOSA model (Modélisation Isentrope du transport Méso-échelle de l’Ozone Stratosphérique par Advection) and adds several modules: a fully explicit size-resolving microphysical scheme to transport aerosol granulometry as passive tracers and an optical module, able to calculate the scattering and extinction properties of particles at given wavelengths. Originally designed for polar stratospheric clouds (composed of sulfuric acid, nitric acid and water vapor), the model is fully capable of rendering the structure and properties of volcanic plumes at the finer scales, assuming complete SO2 oxydation. This link between microphysics and optics also enables the model to take advantage of spaceborne lidar data (i.e. CALIOP) by calculating the 532nm aerosol backscatter coefficient, taking it as the control variable to provide microphysical constraints during the transport. This methodology has been applied to simulate volcanic plumes during relatively recent volcanic eruptions, from the 2010 Merapi to the 2015 Calbuco eruption with detection above the french Antarctic Station Dumont d’Urville. Optical calculations are also used for direct comparisons between the model and groundbased lidar stations for validation as well as characterization purposes. We will present the model and the simulation results, along with a focus on the sensitivity to initialisation parameters, considering the need for quasi-real time modelling and forecasts in the case of future eruptions.
Programme: 209
|
|
