Introduction: Increased temperature as a stress factor in aquatic environments has recently received much attention. Human population growth accompanied by expanded demands for electrical energy has resulted in increased construction of power generating facilities. Conventional fossil fuel power plants are being built to produce many times the electricity of those built in previous years. Nuclear power plants, not economically feasible in small sizes, are being constructed to generate even more electrical energy per unit than the new conventional units. Nuclear power facilities produce heat less efficiently and, thus, require approximately fifty percent more cooling per BTU than usual methods (Kolflat, 1968). Increased exposure of populations and communities of aquatic organisms to thermal pollution can thus be anticipated when natural water systems are utilized as a cooling source. The majority of research effort relative to the effects of heated waste waters on aquatic systems has been directed towards macro- as opposed to micro-organisms. While the use of microorganisms in general pollution monitoring is not a nevi concept; for examples see Kolkwitz and Marsson (1908); Butcher (1947); Fjerdingstad (1962), most of the existing effort has been in the area of correlation of species to various polluted situations. The major disadvantages of such approaches as well as the use of populations and communities of microorganisms in pollution monitoring are discussed in Cairns and Lanza (1971) and Cairns, etc. (submitted)... <i>Vita removed Nov. 30, 2011. GMc</i>Ph. D.