168 Marine Microbiology 



indicator. Two peiTnanent Alnico bar niagnets were mounted 

 perpendicular to the plane, and on either side of the cell at the 

 junction of the tubes "ab" and "cd." These provided a field of 

 about 800 oersteds at the junction. After pumping water through 

 this cell for several hours the indicators showed one of the side 

 arms to be basic while the other was acidic. The probes of a pH 

 meter were then inserted into the agar and a reading taken. 



In the first experiment, tap water containing some bacteria, 

 cells and colloidal material was circulated for four hours. The 

 initial water had a pH of 6.2- while after the experiment the pH 

 in the agar of the side arms of the cell was found to be 5.8:; and 

 6.62 respectively. Repetition of the experiment with raw sea 

 water containing bacteria and colloidal material, but at a slightly 

 lower flow rate and for six hours, showed similar changes but 

 at a smaller magnitude as compared to the tap water. Using a 

 slightly modified glass cell the experiment was repeated, using 

 sea water which had l^een previously filtered through a millipore 

 filter to remove all particulate matter. The results in this latter 

 experiment even after circulation for 24 hours were reduced to 

 only about 0.1 of a pH unit between the two side arms of the cell. 

 It thus appears that filtration removed essentially all of the large 

 charge carriers. The carriers must therefore consist of very large 

 colloids or charge carrying bacteria. 



If one assumes that the ratio of e/m is approximatelv lO'^, the 

 flow rate 20 liters/hour, a tube diameter of 0.5 inches and a mag- 

 netic field of 800 oersteds, it can be shown from equation ( 1 ) that 

 the radius of curvature will be approximately 0.4 centimeters. The 

 measured radius of curvature from the geometry of the cell was a 

 little greater than 0.5 centimeter. It appears that bacteria or 

 possibly large colloids are causing the observed change in pH. 



The experimental data tends to support the hypothesis that 

 the vertical motion of bacteria in the sea is influenced b\' the 

 ocean currents in the horizontal component of the earth's mag- 

 netic field. However, the data so far are much too fragmentary 

 and need to be supported by further experimental work botli in 

 the laboratory and in the field. A more sophisticated laboratory 

 experiment should be performed similar to the one described 

 above and in which radioactive labelled bacteria are used. Tlu^ 



