Professor of Geography, University of the Witwatersrand

I am a biogeochemist interested mainly in environmental change in aquatic systems. My studies have focussed primarily on the impacts of air pollution and climate change on the ecosystems of upland, arctic and alpine lakes and streams using hydrochemical models, stable isotope techniques and palaeolimnology. As a biogeochemist I have also done experimental work with soils, vegetation and trace gas fluxes as well as surface waters. I have worked on international projects in various regions including European mountain lakes, boreal forest lakes in the Oil Sands Region of Alberta, Canada and arctic lakes in Greenland. I am now broadening my interests to look at the multiple pressures on aquatic systems in Southern Africa, including acid mine drainage, eutrophication and acid deposition.

Research Interests:

- Biogeochemical studies of nitrogen and carbon (deposition, soils, vegetation, waters, trace gases)
- Modelling critical loads for fresh waters
- Aquatic monitoring of air pollution and climate change impacts
- Nitrogen stable isotope tracer experiments and natural abundance studies
- Acidification and eutrophication caused by nitrogen deposition
- Acidification and palaeolimnology in remote mountain lakes


  • –present
    Professor of Geography, University of the Witwatersrand