We focus both on processes in the aquatic environment as well as on entire systems of natural waters.
We perform basic and applied research and several projects have a problem-oriented and interdisciplinary focus, including system analysis. Read more
Good arguments for thermal use of surface waters in Switzerland
March 16, 2017 - Switzerland’s surface waters contain vast amounts of thermal energy which could be used for heating or cooling. Based on numerous studies, Eawag scientists have now estimated the ecological impacts of thermal use. Read more
Scaling oxygen microprofiles at the sediment interface of deep stratified waters
Dissolved oxygen microprofiles at the sediment-water interface of Lake Geneva were measured concurrently with velocities 0.25 to 2 m above the sediment. The measurements and scaling analyses indicate dissolved oxygen fluctuations and turbulent fluxes in exceedance of molecular diffusion in the proximity of the sediment-water interface. The measurements allowed the parameterization of the turbulent diffusion as a function of the dimensionless height above the sediment and the turbulence above the sediment-water interface. Turbulent diffusion depended strongly on the friction velocity and differed from formulations reported in the literature that are based on concepts of turbulent and developed wall-bounded flows. The dissolved oxygen microprofiles and proposed parameterization of turbulent diffusion enable a foundation for the similarity scaling of oxygen microprofiles in proximity to the sediment. The proposed scaling allows the estimation of diffusive boundary layer thickness, oxygen flux, and oxygen microprofile distribution in the near-sediment boundary layer.
Biomarkers in Lake Van sediments reveal dry conditions in Eastern Anatolia during 110.000-10.000 years B.P.
Lipid biomarkers were analyzed in Lake Van sediments covering the last 600 ka, with a focus on the period between 110 and 10 ka, when a broad maximum in pore water salinity as a relict from the past suggests dry conditions. The occurrence and distribution of biomarkers indicative for terrestrial plants (long-chain n-alkane C29), haptophyte algae (methyl alkenones C37) and halophilic archaea (archaeol) all point toward a dry climate in Lake Van region during this time interval. The hydrogen isotopic composition of C29n-alkanes (δDC29) and C37 alkenones (δDC37) is enriched between MIS 4 and MIS 2, which is interpreted as a decrease in the regional ratio of precipitation to evaporation. Similarly, the low abundance of the acyclic glycerol dialkyl glycerol tetraether GDGT-0 relative to archaeol, quantified by the Archaeol and Caldarchaeol Ecometric (ACE) is assumed to reflect the presence of halophilic euryarchaeota adapted to high salinity water. The climate around Lake Van appears in phase with the Yammouneh basin 800 km southwest and Lake Urmia 250 km southeast of Lake Van over the last two glacial periods. The results highlight the potential of combining ACE, δDC29, and δDC37 for reconstructing salinity changes and regional precipitation to evaporation ratio from lake sediments.
Randlett,M.E.; Bechtel,A.; van der Meer,M.T.J.; Peterse,F.; Litt,T.; Pickarski,N.; Kwiecien,O.; Stockhecke,M.; Wehrli1,B.; Schubert,C.J. (2017) Biomarkers in Lake Van sediments reveal dry conditions in Eastern Anatolia during 110.000-10.000 years B.P., Geochemistry Geophysics Geosystems, 31 pp., doi:10.1002/2016GC006621, Institutional Repository
The intricacies of Lake Kivu and of the methane stored in its deep waters could easily keep an entire research institute busy. Our research aims at creating the knowledge needed to support a sustainable and safe exploitation of the methane resource.
Wastewater is a source of antibiotic resistant bacteria.
We study their dissemination in the aquatic environment, and strategies to remove them.
Drilliing sediment cores (~600.000 years) from the highly alkaline Lake Van in Anatolia to reveal the climate history.
Lakes store large amounts of heat. To what extent can this heat be used to replace the use of fossil fuels or electricity for heating and cooling purposes?