170 Marine Microbiology 



supplement the geophysical telluric currents. This is clear, how- 

 ever, that where there is a large difference in oxidation-reduc- 

 tion potential between the sea floor and surface waters of the 

 sea, biological forces are actively contributing to the phenomenon. 



Sediment samples collected from regions of high potential 

 difference between the sea floor and the overlying water, such as 

 usually obsei"ved in anaerobic basins of the marine environment, 

 contain large numbers of bacteria and other microorganisms, and 

 invariably a large population of sulfate-reducing bacteria. When 

 such sediments are placed in a laboratory cell designed to measure 

 the emf and electric current flow between the contained sediment 

 and a sample of sea water collected in the same region as the sedi- 

 ment, the observed emf and current usually correlates well with 

 similar measurements taken in situ ( 7 ) . Where correlation is poor, 

 a closer inspection of the field data, which includes oceano- 

 graphic observations of water currents and tidal oscillations, 

 strongly suggest that the induced emf resulting from water move- 

 ment across the magnetic lines of force of the earth either mask 

 or neutralize the biologically induced electric currents expected 

 to occur in the region. 



Using specially designed probes to measure both emf and 

 electric currents on the sea floor and between the sea floor and 

 overlying water, fluctuations in voltage and current have been 

 observed during continuous recordings at an anchored station 

 (8). It is believed, although not conclusively proven at this time, 

 that such fluctuations, in some instances appearing as a low 

 frequency oscillating current, are caused by the above mentioned 

 interrelation between water movement and the earth's magnetic 

 field. It is also believed, but not proven, that magnetically in- 

 duced variations in emf and electric currents affect the physiology 

 of the microflora in the sediments. Isolated microorganisms, when 

 placed in an electrolytic cell, display changes in physiological 

 processes and in orientation when the electric current in the cell 

 is reversed by an outside power source. The authors are presently 

 conducting laboratory tests to assess both direct and indirect ef- 

 fects of magnetic fields on the functions of microorganisms. 



ACKNOWLEDGMENT 



The authors wish to thank Dr. George B. Findley, U. S. Navy 



