Volume of Abstracts - Università degli Studi di Milano

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5 th Int. Workshop on Ice Caves (IWIC – V) Barzio (LC), Valsassina, Grigna and Milano, September 16 – 23, 2012 Volume of Abstracts LEAD CONCENTRATIONS AND STABLE LEAD ISOTOPES FROM A CROATIAN CAVE ICE PROFILE Kern Z. 1,2 , Széles, É. 3 & Boţiš N. 4 1 Climate and Environmental Physics, Physics Institute, University of Bern and Oeschger Center for Climate Change, Bern, Switzerland 2 MTA CSFK, Institute for Geological and Geochemical Research, Budapest, Hungary 3 Centre for Energy Research, Department of Nuclear Security, Hungarian Academy of Sciences, Budapest, Hungary 4 Department of Geography, University of Zagreb, Zagreb, Croatia Vukušiš Ice Cave (Vukušiš snijeţnica, 44.8N, 14.98E 1490 m asl) is located near the Zaviţan Peak in the northern Velebit Mountains. Thickness of its ice deposit is estimated to be more than 10 m. Lead concentration and stable lead isotopes were analysed on 36 samples of a 2 m long ice core extracted from the ice deposit on 28.10.2008. Pb concentration record is characterized by an overall increasing trend toward the surface. Topmost sample showed the highest Pb concentration, while an interesting secondary maximum emerged between 0.59 and 0.81 m depth. 206 Pb/ 207 Pb ratio is characteristically below the expected regional geogenic background (1.202-1.245). Samples from the 1.34-1.49 m depth range, with highly elevated mud content in the ice profile, provided the best agreement (mean 206 Pb/ 207 Pb: 1.235) with the expected geogenic background. The rest of the profile showed a slightly decreasing trend towards the surface. The minimum was found in the topmost sample ( 206 Pb/ 207 Pb: 1.069). Ternary plot of 206 Pb/ 207 Pb/ 208 Pb shows a gradual shift from a dominantly geogenic composition toward the Broken Hill galena used as antiknock additive in European petrol during the second half of the 20 th century. Cave ice record documented an increasing lead contamination being in line with the regional 20 th century lead contamination history. Lead isotope ratios provide evidence that increased lead concentrations are due to the increased anthropogenic contribution. The estimated age of the 2 m cave ice core (c. 1950-1980) based on lead concentration and lead isotopes agrees with earlier tritium measurements and the expected lost of most recent accumulation due to negative surface ice mass balance observed in the first decade of the 21th century. 39
5 th Int. Workshop on Ice Caves (IWIC – V) Barzio (LC), Valsassina, Grigna and Milano, September 16 – 23, 2012 Volume of Abstracts MICROBIOLOGY IN ALPINE AND ANTARCTIC ICE AND GLACIER CAVES Sattler B 1 ., Standhartinger B. 2 , Hoover R. 3 , Wendlinger C. 3 , Spötl C. 4 & Psenner R. 1 1 University of Innsbruck, Institute of Ecology, Technikerstrasse 25, 6020 Innsbruck, Austria 2 Wasser Tirol,Gewerbestraße 4, 6430 Ötztal-Bahnhof, Austria 3 NASA/NSSTC, Huntsville, Alabama 35802, USA 4 University of Innsbruck, Institute of Geology and Paleontology, Innrain 52, 6020 Innsbruck, Austria (birgit.sattler@uibk.ac.at) Ice and glacier caves in alpine and polar regions have been lately recognized as microbial habitats. They consist truncated food webs consisting of viruses, fungi, bacteria and autotrophic organisms such as cyanobacteria and (snow) algae) exerting photosynthesis which is mostly limited to the cave entrance. Ice caves in general are understood as rock caves with remaining permanent ice with a seasonal change of thickness providing a relatively stable environment. Contrary to the relatively stable environment of this type glacier caves do not provide a rock bed and are highly dynamic due to the plasticity and movement of the glacier. Hence, caves in glaciers can as well disappear for a while or close up. However, due to limited but still existing transparency of the overlying ice cyanobacteria can still thrive and provide carbon for heterotrophic bacteria. Here we present the comparison of the two types located in the Austrian Alps (Grubsteinhöhle and Hintertuxer Eispalast) and glacier caves from Antarctica (Novolazarewskaya and Dumar glacier cave) based on chemical characterization of the ice and the consisting bacterial communities. Molecular biological results from the ice cave revealed largely different microbial communities in ice cores, sediment and air. Ice cores of all habitats contained Actino-, Cyano- and Proteobacteria whereas Acidobacteria and Deinococcus-Thermus have only been found in Antarctic caves. Ice caves are also understood as a refuge for microbial cells and are hence model habitats for astrobiological hypotheses. 40
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Page 4: President 5 th Int. Workshop on Ice
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Page 13 and 14: Dear Participants, we are very plea
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