Dr. Katrin Wendt-Potthoff

Reserach Interests

My research interests comprise miscellaneous aspects of aquatic microbiology and biogeochemistry. I am especially interested in the influence of micro-organisms on geochemical processes.
Current work focuses on the microbiology of stratified lakes, in particular the anaerobic processes in sediments and at boundary layers (chemoclines) in the water column. Of special interest is the interaction of iron, manganese and sulfur cycling and the zonation of biogeochemical processes. I currently investigate three different types of lakes. These are firstly reservoirs, where I study the relative contributions of different microbial respiratory processes to carbon cycling. Release of manganese to the water column is a key issue here. Secondly, I investigate meromictic acidic pit lakes in Spain, where iron and sulfur cycling are quantified and the potential for natural neutralization is estimated, based on long-term experience with acid lakes in Lusatia, Germany (Spain project). Third of all, in the framework of a German-Canadian project initiative I study tailings ponds and end pit lakes which result from oil sands extraction in Canada (HAI Oil Sands Tailings Ponds project). The focus of this research is the sulfur cycle and its regulation, in order to stimulate precipitation of metals and degradation of organic contaminants, and to limit the release of toxic hydrogen sulfide.
In addition to biogeochemical processes I study the microbial populations in these partly extreme habitats. Steep gradients of pH-value and oxygen, high concentrations of dissolved inorganic substances, and accumulation of humic substances or toxic organic acids may select for organisms which tolerate these conditions. Beyond that, such organisms might contribute to an improvement of the water quality. Finally, I am interested in microbial bioconversion of external carbon sources, mainly natural terrestrial or aquatic organic matter.