Summary: Hydrobiologia 487: 111136, 2002.
© 2002 Kluwer Academic Publishers. Printed in the Netherlands.
The physical structure and dynamics of a deep, meromictic crater lake
(Lac Pavin, France)
Werner Aeschbach-Hertig1,3, Markus Hofer1, Martin Schmid2, Rolf Kipfer1,4 &
Dieter M. Imboden3
1Water Resources and Drinking Water,
2Applied Aquatic Ecology, Swiss Federal Institute of Environmental Science and Technology (EAWAG),
CH-8600 Dübendorf, Switzerland
4Isotope Geochemistry and Mineral Resources, Swiss Federal Institute of Technology (ETH),
CH-8902 Zürich, Switzerland
Received 20 September 2002; accepted 20 September 2002
Key words: tritium, helium, CFCs, density stratification, turbulent diffusion, lake modeling
The characteristic feature of the physical structure of Lac Pavin is a distinct and permanent chemically induced
density increase between about 60 and 70 m depth. This chemocline separates the seasonally mixed mixolimnion
from the monimolimnion, which is characterized by elevated temperature and salinity as well as complete anoxia.
Previously published box-models of the lake postulated substantial groundwater input at the lake bottom, and