664 TANSEY AND FLIERMANS 



stress, additional species of thermophilic and thermotolerant fungi 

 occur and grow (Tansey and Jack, 1976; 1977; Jack and Tansey, 

 1977; Tansey and Brock, 1978), Thermophilic and thermotolerant 

 fungi thrive at body temperatures, and several species are zoopatho- 

 gens (Tansey and Brock, 1978). Stresses other than high temperature 

 limit growth of thermophilic and thermotolerant fungi in the body; 

 the immune response of a normal human usually prevents serious 

 infection. 



This paper describes the diverse populations of thermophilic and 

 thermotolerant fungi found in foam, water, microbial mats, plant 

 debris, air, and soil at elevated and ambient temperatures at the U. S. 

 Department of Energy's Savannah River Plant (SRP). Savannah River 

 water is heated when it is pumped through heat exchangers to cool 

 nuclear production reactors. These reactors, which are designed to 

 produce nuclear materials for space, civilian, and military applica- 

 tions, differ significantly from nuclear reactors designed for 

 electrical-power production in that effluent temperatures are fre- 

 quently higher than 70° C. Heated effluents from SRP reactors 

 provide habitats in which pH values are not extreme, and host 

 immune responses do not limit growth of thermophihc and thermo- 

 tolerant fungi. In these effluents temporal variation in thermal stress 

 occurs over periods of time that are long in comparison with the life 

 cycles of the fungi and thus provide "constant" temperature 

 habitats. 



MATERIALS AIMD METHODS 



Samples were collected in late spring and in summer. General 

 sites from which samples were obtained are identified in Figs. 1 and 

 2. The P Canal, Ponds 2, 4, and 5, and Par Pond receive thermal 

 effluent from P Reactor, and Four Mile Creek receives heated 

 effluent from C Reactor. On the other hand. Steel Creek has not 

 received effluents for the past 9 years, and Upper Three Runs Creek 

 and Intake Canal No. 1 on the Savannah River receive no heated 

 effluents. At the Flowing Streams Laboratory, water from Upper 

 Three Runs Creek is heated to a temperature differential of 25°C 

 before being released through artificial channels (Harvey, 1973). 



Water samples from each site were collected by plunging sterile 

 tubes to a depth of 5 to 10 cm with flamed forceps, allowing the 

 tubes to fill completely, and closing them with a screw cap. Water 

 temperature was measured at the collection site, and pH was 

 measured in the laboratory. One milliliter of each sample was spread 



