Experiments Regarding the Sulfide Formation in Sediments 683 



tent in organic bound sulfur. We determined the total-sulfur 

 and the sulfate-sulfur. The results are shown in Table 1. 



DISCUSSION 



Our experiments show that different amounts of sulfide are 

 formed in different sediments. In no experiment was the decrease 

 of sulfate the same as the increase of sulfides. In some experi- 

 ments different amounts of non-SO i sulfur are transfonned into 

 sulfide, in other experiments a part of the sulfate is transformed 

 into other forms than sulfide. With our methods we found, in 

 all experiments, much higher bacterial numbers of organic H-S- 

 producers than sulfate-reducers. 



Further experiments, in addition to the used techniques, are 

 planned, including determinations of elementary sulfur, deter- 

 minations of the different organic sources and tracer experiments. 



SUMMARY 



Model experiments regarding the sulfide production in sedi- 

 ments rich in organic matter were conducted at the Texas Gulf 

 Coast and in Helgoland, Germany. Chemical determinations of 

 different sulfur compounds, organic bound carbon. Eh, and the 

 bacterial numbers of aerobic-, anerobic -, sulfate-reducing - and 

 organic-HsS producing bacteria were accomplished. 



ACKNOWLEDGMENTS 



The authors would like to thank Mrs. Doris Blanton, Mrs. 

 Eva Kriiss, Mr. Floyd Clark and Mr. H. H. Trekel for their 

 technical assistance. This work was supported at the Institute of 

 Marine Science, University of Texas by grant Nonr 375 ( 10) from 

 the Office of Naval Research. 



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1. American Public Health Association, Inc.: Standard Methods for the 



Examination of Water Sewage and Industrial Wastes, New York, 

 1955. 



2. Bunker, H. J.: A Review of the Physiology and Biochemistry of the 



Sulfur Bacteria, H. M. Stationery Office, London, 1938. 



3. Kriss, A. E., et a/.: Morskaya microbiologiya (glubokovodnaya) (Deep- 



sea Microbiology). Akad. Nauk, SSSR, 455 p. (in Russian) 1959. 



