1979 - 1984	Student assistant at Institute of Geology at the University of Muenster
1981 - 1984	Research assistant at the University of Essen
1984	Post doctoral research fellow at the California State University, Long Beach, USA
1984 - 1986	Research assistant at the University of Essen
1986 - 1992	Assistant professor at the University of Essen
1986	Research stay in Australia, Geological Survey W.A., Perth and Kalgoorlie
1987	Research stay at Rand Afrikaans University, Johannesburg, South-Africa (founded by Heinrich Hertz-Foundation)
1988 - 1992	Scientific Editor of the Journal GEOWISSENSCHAFTEN, VCH Weinheim
1990	Research stay at the Harvard University, Boston, USA (founded by Heinrich Hertz-Foundation)
1991 - 1992	Scientific lectorate GEOWISSENSCHAFTEN, Akademic Publisher, Berlin
1992 - 1993	Senior Scientist at the University of Essen
1992	Research stay at the University of Hawai'i, Manoa (founded by German Research Foundation DFG)
1993 - 2001	Secretary-General of the German Advisory Council on the Environment at the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety
1993 - 1998	Teaching and research work at the University of Essen
1994	Appointment as Director and Professor
1998 - 2001	Research and Teaching at the Johannes Gutenberg University, Mainz, Institute for Applied Geology
since 2001	Director of the Leibniz-Centre for Agricultural Landscape Research e. V. (ZALF) Muencheberg
2001	Appointment as Professor for Geoecology at the Universityof Potsdam