Chapter VIII — 145 — Distribution 



It has been recently established that the actinomycetes found in water 

 basins, especially in lake bottoms, are largely members of the genus 

 Micromonospora. 



Erikson (113) isolated from lake mud, and in one instance from 

 lake water, ten strains of Micromonosfora chalcea. These forms were 

 found capable of growing on a large variety of more or less resistant or- 

 ganic compounds and were especially active in the decomposition of 

 chitin, cellulose, pentosans, glucosides, and, to a lesser degree, of lignin. 

 It was suggested that the Microvionosfora types, because of the resist- 



Tadle 36 : fnflueiice of temperature upon the development of microorganisms in 



manure composts (459) : — 



Per gram of moist compost 



ance of their spores, may be better adapted to life under aquatic condi- 

 tions than are other actinomycetes with aerially borne spores. 



Umbreit and McCoy (433) found that 10 to 20 per cent of the 

 total microbiological population found in the water of the lakes of the 

 northern highland region of Wisconsin comprised species of the genus 

 Microvionospora. In some cases these numbers were as high as 40 per 

 cent, as in the surface water of Trout Lake, with a total of 250 organisms 

 per milliliter. The water of Crystal Lake contained 3,600 organisms 

 per milliliter, of which 16 per cent were made up of members of the 

 genus Micromonosfora. Even larger numbers of these organisms were 

 found in the bottoms of the lakes. The deposit of Lake Mendota, 



