Role of Microbes in Genesis and Weathering of Sulfur Deposits 173 



TABLE 1 



Sulfur, Carbonates axd Quartz Sand in the Sediments of Balkasch Sea 

 (Per Cent of Dry Weight) 



TABLE 2 



Vertical Distribution of Desulfurizing Bacteria/ml in the Sediments of 



Some Salt Lakes. 



Depths Balkasch Lake 



of Unireschewo Mogilnoje Maibalyk Containing 



Sediment Lake Lake Lake Repnoje Epsomite 



(m) (Eutrophic) (Eutrophic) ( Mesotrophic) Lake (MgSO- 7 H^O) 



1,000 300 500 100,000 500 



0.25 



0.50 1,000 



1.0 



2.0 



3.0 



4.8 



6.0 



7.8 



lake 19 mg H-S/L are produced daily (4). Ivanov (3) has found 

 high numbers of Thiobacterium^ and of purple-sulfur microbes 

 in the sulfur containing sediments of Sernoje lake. About 30 per 

 cent of the sulfides in the lake water are o.xidizcd to sulfur by 

 Thiobact. thioparum. Purple-sulfur-microbes oxidize sulfur to 

 sulfate. In the littoral or Belvod lake, only the sediment contains 

 H2S in quantities of 150-500 mg/L and rH- becomes low onl\' at 



^ Thiohacterium Lehm. et Neuni., nov comb, of Krassilnikow (7) corresponds to 

 Thiobacillus Bei'j. of Bergey's Manual. 



