University of Toronto
Department of Earth Sciences
22 Ursula Franklin St., Toronto
Ontario, Canada M5S 3B1
1. Impact of microorganism on the interfacial chemistry of surfaces (rock-fluid-biofilm interactions), particularly with respect to the carbonate-silicate weathering cycle.
Research in this area is directed in three directions:
- studies on the geochemistry of epilithic microbial biofilms in acid mine drainage environments,
- characterization of complex iron-aluminium-silicate phases precipitated by epilithic microbial biofilms in fresh water environments, and
- evaluation of the impact of microbial carbonate precipitation on the weathering of silicate minerals in basic rocks of recent volcanic flows in Iceland and flood basalts of central British Columbia.
2. Formation of minerals by microorganisms in ancient and modern sediments, and porous subsurface environments.
A number of different microbial mineral forming processes are being examined. These include gold precipitation by microbial cell derived organic matter, formation of authigenic magnesium silicate minerals in cyanobacterial mats, and iron-oxyhydroxide mineral precipitation by microorganisms in groundwater discharge zones. Laboratory work is also being used to assess the role of hydrogen-oxidizing sulfate-reducing bacteria in the formation of pyrite, and experimental studies are being done on the production of methane by microbial biofilms from boreholes in mines.
3. Mechanisms of microbial fossilization.
These studies are focused on the role of silicification in the preservation of cellularly intact cyanobacterial microfossils in outflow channels of hot springs in Iceland.