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News from the AWI Potsdam

The 13th Russian-German-Expedition Lena Delta 2010 took place from July to November with 55 participants. The overall aims are to continue the ongoing research on carbon, water and energy cycling, coastal erosion, land-sea interaction and paleoclimatic reconstruction, carried out on the tundra in and around the Lena Delta, the shallow coastal seas and on a N-S transect for lake studies and lake sediment sampling. The activities were concentrated on the German-Russian Samoylov station on an island in the middle of the delta. The building of a new station has started this summer on an area more inland of the island, because of increasing river shore erosion close to the old station. The visit of the Russian Prime Minister Vladimir Putin at Samoylov station on August 23, 2010, was a highlight of the expedition. During his stay on Samoylov Putin was informed about the research carried out especially the long term monitoring sites. He showed his deep interest in the permafrost studies during a long discussion with scientists and students.


Russian prime minister Vladimir Putin at Samoylov station, Lena delta (Photograph provided by Günter Stoof)

Measurements of climate, energy and water fluxes and permafrost thermal dynamics were continued at the field sites in Spitsbergen (Ny Alesund), Siberia (Lena Delta) and Canadian High Arctic in cooperation with Hamburg University and York University. Furthermore, spatial distributed mapping of arctic land cover and terrain features using ground based measurements and satellite images was carried out. The long-term studies on methane fluxes on Samoylov were continued in cooperation with the Forest Institute in Krasnoyarsk. Furthermore a global warming simulation experiment using open top chambers was started to study the effect of rising environmental temperatures on microbial community structure and stability.

The coast of the Buor Khaya Peninsula (southern Laptev Sea) was used to study permafrost degradation as well as the modern periglacial environment by a group of nine colleagues from Potsdam, Yakutsk, St. Petersburg and Tiksi in August 2010. Survey of the coastal geomorphology and stratigraphy were carried out to improve coastal classification and to establish an initial survey of coastline position for change rate determination and comparison with remote sensing products. Geoelectric methods were used to measure the bathymetry, to detect the penetration depth of the salt front into the sediment, and the upper surface of the ice-bonded permafrost. The apparent resistivity of the sediment was measured, surface sediments were collected and the temperature and salinity at the sea bed during the summer high temperature period were logged. In addition proposed drilling sites were characterized in terms of bathymetry and permafrost depth, via inversion of observed apparent resistivity. Various permafrost profiles along the shore were studied to develop a stratigraphic differentiated carbon balance and characteristic, relating the transformation of organic matter with the permafrost dynamics during the last late Quaternary climatic cycle, as well as examining the stability and/or degradation of the organic carbon fixed in permafrost. The expected cryolithological and stratigraphical results will be used to complete and to correlate paleoenvironmental datasets around the Laptev and East Siberian seas obtained since 1998.

In the Laptev Sea, the AWI, the University of Bremen, the University of Cologne, the Otto Schmidt Laboratory (RU) and the St. Petersburg State University (RU) intensified joint hydro-biogeochemical investigations on land and in coastal to marine waters. The expedition and research activities will result in more insight into the hydrological dynamics, and the residence times, transport, and erosion of organic matter in permafrost from source to sink.

The AWI also pursued its collaboration with McGill University for the sixth year in a row. A group of four scientists from Germany travelled to Herschel Island and the Yukon Coastal Plain to conduct paleogeographical studies (a core was retrieved from the coast 14km east of the Alaska border), coastal thermokarst studies (a monitoring station was installed to quantify the sediment and nutrient release from retrogressive thaw slumps) and microbiological studies (closed chamber measurements to study the release of CH4 and CO2). Two scientists from the German Research Centre for Geosciences joined the group to measure atmospheric methane concentrations at ground level.

On November 8-11, 2010 a joint Russian-German workshop on research in the Laptev Sea region was organized by the Otto Schmidt Laboratory (OSL), the Arctic and Antarctic Research Institute (AARI) and the Alfred Wegener Institute (AWI) in St. Petersburg, Russia which attracted a group with broad interests. Over 60 participants registered, about half of whom were Russian and half German to foster multi-disciplinarity, to provide a venue for exchange of results and experiences and to plan and co-ordinate future activities. The necessity for a meeting between Russian and German researchers working in the Laptev Sea Region is a direct result of the intense activity and the history of co-operative work that has occurred there over the past two decades in winter and summer months, on land, on the water and on the ice surface.


Joint fieldwork on Samoylov Island, Lena River Delta: students are sampling for hydro-biogeochemical parameters and dissolved and particulate organic carbon. (Photograph provided by Birgit Heim).

News from German universities

At the University of Giessen, S. Imbery started his dissertation on the contribution of permafrost and snow to the water balance under climate change conditions. In this DFG-funded Aksu-Tarim-Cryo project, field studies are carried out in the Aksu catchment, Central Tian Shan (China) in cooperation with CAREERI Lanzhou (Gao Qiangzhao and Li Zhongqing) a dense network of ground temperature loggers were installed to study the active layer dynamics and permafrost distribution at altitudes between 3,400 and 4,150 m a.s.l.. Similar studies were started in the Kyrgyz Tianshan by M. Duishonakunov in cooperation with the CAIAG Bishkek with joint supervision of this dissertation by R. Usubaliev and L. King. Two PhD students of this Giessen periglacial working group (T. Keller, I. Polenthon) started periglacial studies on the role of frost processes for the mudflows occurring quite often along the Georgian military road, Greater Caucasus, Georgia.

At the technical university of Munich (TU, chair of geomorphology and soil science, centre of life and food sciences Weihenstephan), studies on mountain permafrost distribution and degradation were continued at Green Lakes Valley, Colorado Front Range between 3.600 to 4000 meters a.s.l.. The studies are embedded in the NSF-funded Boulder Creek Critical Zone Observatory and Niwot Ridge Long-Term Ecological Research, and aim to understand ongoing alterations in the subsurface. M. Leopold and J. Völkel conducted geophysical surveys using electrical resistivity tomography and shallow seismic refraction together with ground penetrating radar for permafrost studies within the critical zone (CZ). Selective sites mapped with underlying permafrost in the 1970’s have been re-studied in order to portray changes in the CZ: Whereas small rock glaciers seem to be rather stable, solifluction lobes transformed from permafrost to sites with annual ice lenses. Collaboration with M. Williams and N. Caine from INSTAAR at CU Boulder offers possibilities to combine observable changes in the hydrochemistry of permafrost sites outflows over the past years, in combination with long-term climate records and geophysically-based data of permafrost variations, which possibly allows new approaches in permafrost degradation prognosis.


ERT survey in winter on the rock glacier near Green Lake 5 at 3.600 m a.s.l. (Photograph provided by M. Leopold)

At the University of Würzburg, D. Schwindt continued his PhD thesis research on spatial and temporal permafrost variability regarding ground thermal regime and permafrost-humus interaction in talus slopes below the timberline (Swiss Alps) by applying a year-round refraction seismic monitoring. Repeated geoelectrical and seismic surveys are conducted at a small glacier forefield at Piz Corvatsch (Engadin, Swiss Alps) by T. Rödder. In addition, temperature data from boreholes are analyzed to investigate and monitor changes in ground characteristics within these unconsolidated sediments. N. Roth has finished his dissertation about temperature -resistivity monitoring and thermal offset studies within the Muragl glacier forefield (Swiss Alps). Recent alpine permafrost dynamics (J. Kästl) and the geomorphological activity of different typical subarctic landforms (P. Konrad) are currently investigated within two diploma theses using a combined geophysical and photogrammetrical approach.

(Lorenz King, lorenz.king@geogr.uni-giessen.de)