Chapter 2 



Geological Activities of Marine 

 Micro-organisms 



WiLHELM Schwartz 



I 



do not intend to give a summary of the papers presented in 

 session B2 of our symposium, as I believe, if one is interested, 

 it is better to read the papers themselves. It seems to be more 

 important to discuss the general aspect of the relations between 

 microbes and geochemical and geological processes imder marine 

 conditions, at least for some problems, because it is impossible 

 to discuss all the topics within the frame of our symposium. 



In this discussion it will soon become obvious that we are 

 just at the beginning of an understanding of geomicrobiology. 

 Of course, we know already a great many facts about biocenosis 

 and biotopes, about mutual relations of microbes among them- 

 selves or between microbes and other organisms in the sea, and 

 in marine sediments; and about biochemical activities under 

 laboratory conditions and sometimes under natural conditions. 



Also one should not neglect to compare marine, brackish 

 and limnic conditions if tlie specific features of life in a marine 

 environment are to be understood. Often the distinct environ- 

 ments are quite obvious, but by no means always. 



The following are but a few of the important facts and 

 suppositions which we have to consider when discussing geomi- 

 crobiological acti\'ities. In my laboratory we are studying, under 

 marine conditions, the activity of microbes in relation to sedi- 

 mentation, diagenesis and weathering, including: the effects of 

 organic and inorganic compounds in the biotope; of high and low 

 temperature; of osmotic pressure and water pressure and so on; 

 to the cycle of some elements and chemical compounds which 

 are important for life processes and at the same time significant 

 for geochemical or geological processes, e.g., Fe, Mn,. S, Si, CO2, 



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