@article{GlombitzaStockheckeSchubertetal.2013, author = {Glombitza, Clemens and Stockhecke, Mona and Schubert, Carsten J. and Vetter, Alexandra and Kallmeyer, Jens}, title = {Sulfate reduction controlled by organic matter availability in deep sediment cores from the saline, alkaline Lake Van (Eastern Anatolia,Turkey)}, series = {Frontiers in microbiology}, volume = {4}, journal = {Frontiers in microbiology}, number = {28}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2013.00209}, pages = {12}, year = {2013}, abstract = {As part of the International Continental Drilling Program deep lake drilling project Paleo Van, we investigated sulfate reduction (SR) in deep sediment cores of the saline, alkaline (salinity 21.4\%0, alkalinity 155 m mEq-1, pH 9.81) Lake Van, Turkey. The cores were retrieved in the Northern Basin (NB) and at Ahlat Ridge (AR) and reached a maximum depth of 220 m. Additionally, 65-75 cm long gravity cores were taken at both sites. SR rates (SRR) were low (<22 nmol cm-3 day-1) compared to lakes with higher salinity and alkalinity, indicating that salinity and alkalinity are not limiting SR in Lake Van. Both sites differ significantly in rates and depth distribution of SR. In NB, SRR are up to 10 times higher than at AR. SR could be detected down to 19 mblf (meters below lake floor) at NB and down to 13 mblf at AR. Although SRR were lower at AR than at NB, organic matter (OM) concentrations were higher. In contrast, dissolved OM in the pore water at AR contained more macromolecular OM and less low molecular weight OM.VVe thus suggest, that OM content alone cannot be used to infer microbial activity at Lake Van but that quality of OM has an important impact as well. These differences suggest that biogeochemical processes in lacustrine sediments are reacting very sensitively to small variations in geological, physical, or chemical parameters over relatively short distances.}, language = {en} } @article{GlogerTippeltVetterRauh2000, author = {Gloger-Tippelt, G. and Vetter, J. and Rauh, Hellgard}, title = {Untersuchungen mit der "Fremden Situation" in deutschsprachigen L{\"a}ndern : ein {\"U}berblick}, year = {2000}, language = {de} } @article{AichLierschVetteretal.2014, author = {Aich, Valentin and Liersch, Stefan and Vetter, T. and Huang, S. and Tecklenburg, J. and Hoffmann, P. and Koch, H. and Fournet, S. and Krysanova, Valentina and Mueller, N. and Hattermann, Fred}, title = {Comparing impacts of climate change on streamflow in four large African river basins}, series = {Hydrology and earth system sciences : HESS}, volume = {18}, journal = {Hydrology and earth system sciences : HESS}, number = {4}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1027-5606}, doi = {10.5194/hess-18-1305-2014}, pages = {1305 -- 1321}, year = {2014}, abstract = {This study aims to compare impacts of climate change on streamflow in four large representative African river basins: the Niger, the Upper Blue Nile, the Oubangui and the Limpopo. We set up the eco-hydrological model SWIM (Soil and Water Integrated Model) for all four basins individually. The validation of the models for four basins shows results from adequate to very good, depending on the quality and availability of input and calibration data. For the climate impact assessment, we drive the model with outputs of five bias corrected Earth system models of Coupled Model Intercomparison Project Phase 5 (CMIP5) for the representative concentration pathways (RCPs) 2.6 and 8.5. This climate input is put into the context of climate trends of the whole African continent and compared to a CMIP5 ensemble of 19 models in order to test their representativeness. Subsequently, we compare the trends in mean discharges, seasonality and hydrological extremes in the 21st century. The uncertainty of results for all basins is high. Still, climate change impact is clearly visible for mean discharges but also for extremes in high and low flows. The uncertainty of the projections is the lowest in the Upper Blue Nile, where an increase in streamflow is most likely. In the Niger and the Limpopo basins, the magnitude of trends in both directions is high and has a wide range of uncertainty. In the Oubangui, impacts are the least significant. Our results confirm partly the findings of previous continental impact analyses for Africa. However, contradictory to these studies we find a tendency for increased streamflows in three of the four basins (not for the Oubangui). Guided by these results, we argue for attention to the possible risks of increasing high flows in the face of the dominant water scarcity in Africa. In conclusion, the study shows that impact intercomparisons have added value to the adaptation discussion and may be used for setting up adaptation plans in the context of a holistic approach.}, language = {en} }