Tebo, B. M.. Scripps Institution of Oceanography, btebo@ucsd.edu
, . M.. ,

 
THE ROLE OF BACTERIA IN THE NATURAL ATTENUATION OF METAL POLLUTION IN AQUATIC ENVIRONMENTS
 
Bacterially catalyzed metal redox reactions can lead to the transformation of metals from their soluble to precipitated forms. The precipitated forms of the metals are relatively biologically unavailable and hence less toxic. In addition the solid phases often act as scavengers of other metals and participate in other redox reactions. These metal transformations can be catalyzed by bacteria either directly or indirectly via chemical intermediates. In oxic and suboxic waters, the microbial oxidation of iron and manganese can lead to the formation of metal oxides which adsorb a variety of heavy metals and act as oxidants for reduced organic and inorganic chemical species. In the absence of oxygen, many bacteria are capable of reductively precipitating metals and metalloids. Dissimilatory metal-reducing and sulfate-reducing bacteria are two biogeochemically important groups of bacteria that precipitate metals. Metals either precipitate through the decreased solubility of the reduced metal species or form insoluble complexes, such as metal sulfides, with microbially produced intermediates. In turn, these precipitates also scavenge additional metals. For example, the metal scavenging properties of iron sulfide are well known. All of these microbially-catalyzed processes, many of which involve redox reactions, are important for the natural attenuation of metal pollution in the environment.
 
Day: Monday, Feb. 1
Time: 03:30 - 03:45pm
Location: Hilton of Santa Fe
 
Code: SS06MO0330H