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4.1. GROUNDWATER AND PALEOCLIMATE 151
Overview
The research group ”Aquatic Systems” investigates freshwater systems, in particular lakes and groundwater,
using direct measurements of physical parameters as wells as tracer and isotope methods. The
fundamental goal of this research is to obtain a better understanding of the physical processes in these
systems. Examples of studied processes are vertical turbulent mixing, currents, and tracer transport
in stratified lakes, or recharge, flow, dispersion and contaminant transport in aquifers. A further important
field is the use of aquifers as paleoclimate archives. The wider context of our research includes
the issues of water resources protection and management, and assessment of past and present climate
change.
The group is divided in two subgroups: ”Groundwater and Paleoclimate” and ”Limnophysics”.
4.1 Groundwater and Paleoclimate
Names of group members
Prof. Werner Aeschbach-Hertig, head of group
Dr. Reinhold Bayer, administration
Dr. Hany El-Gamal, PhD-student (completed June 2005)
Dipl. Phys. Ronny Friedrich, PhD-student
Dipl. Phys. Rainer Klement, diploma student (completed February 2005)
Dipl. Phys. Tobias Kluge, PhD-student
Dipl. Phys. Andreas Kreuzer, PhD-student
Dr. Laszlo Palcsu, postdoc
M. Sc. Sarah Rice, master student (completed December 2004)
Dipl. Phys. Katja Träumner, diploma student (completed November 2005)
Martin Wieser, diploma student
Dipl. Ing. Gerhard Zimmek, technician
Abstract The research group ”Groundwater and Paleoclimate” deals with applications of isotope
and environmental tracers, in particular noble gases, in groundwater (and lakes in collaboration with
the Limnophysics group). With theses methods, the group pursues two main aims: 1. To provide foundations
for a sustainable management of groundwater resources, 2. Reconstruction of the paleoclimate
since the last ice age.
Background The overarching topic of our research may be summarized as ”isotope hydrology and
climatology”, more specifically the use of isotopes and other environmental tracers (in particular noble
gases) to study the functioning of groundwater systems and to extract paleoclimatic information from
them.
Isotope and tracer techniques have a long tradition in environmental physics. In addition to the widely
used stable isotopes, dissolved noble gases in groundwater have been established as a reliable paleotemperature
proxy. Furthermore, 3 H, He isotopes and other transient gas tracers are important tools
in groundwater dating and recharge assessment [e.g. Kipfer et al. , 2002]. Groundwaters constitute
by far the largest global reservoir of available fresh water. For the sustainable management of these
resources, particularly in arid and semi-arid regions, it is essential to understand on what time-scales
these resources are renewed and how they react to global climate change. Climate change and the
limited availability of water resources are interrelated issues of increasing global importance. Isotopic
studies of groundwaters yield information on both past climatic conditions such as temperature or
aridity and on physical parameters such as residence time or recharge rate. Thus, issues of past climatic
conditions and future availability of groundwater resources can be addressed in an integrated
approach.
Methods A central facility of the group is the newly built mass spectrometric system for the analysis
of noble gases dissolved in water. It is currently becoming operational and will allow measurements
of all stable noble gases from groundwaters for paleotemperature studies as well as the analysis of
He isotopes for 3 H- 3 He dating. This facility is also being used to study new sample types such as
stalagmites. It is complemented by an older system for He isotope analysis and a radiometric 3 H
lab. Furthermore, the group conducts gas chromatographic SF6 analyses in cooperation with the
limnophysics group, and uses the stable isotope and 14 C laboratories of the institute.