PRELIMINARY STUDIES ON THE VIABILITY AND 

 DISPERSAL OF COLIFORM BACTERIA IN THE SEA* 



B7 BOSTWICK H. KETCHUM, CORNELIA L. CAREY, AND MARGARET BRIGGS 



WOODS HOLE OCEANOGRAPHIC INSTITUTION, WOODS HOLE, MASS. 



The disposal of sewage in the sea is widespread and increasing. There 

 is, however, little information to indicate how much sewage a given body 

 of water will accommodate and even less on the fate of the pollution bac- 

 teria in the sea. The economic effects of polluted estuaries are already 

 evident, since large areas have been closed for the taking of shellfish and 

 many beaches throughout the country have been posted as unsatisfactory. 

 These problems will probably become more acute, because the disposal of 

 sewage is essential and the sea provides an eflBcient means of dispersion. 



Harbors and estuaries frequently contain many thousands of bac- 

 teria per ml, a large proportion of which may be enteric species. In the open 

 sea, however, the bacterial counts normally range from 50-200 per ml, 

 and the coliform bacteria are never found in open, unpolluted sea water. 

 This tremendous decrease in numbers occurs within a short distance from 

 the mouth of the harbor or estuary (Calif. State Dept. Pub. Health 1943; 

 Knowlton 1929; Mass. Dept. Pub. Health 1936; Warren and Rawn 1938; 

 Weston 1938; Winslow and Moxon 1928). It is clear, therefore, that the in- 

 troduced bacteria do not persist for extended periods in the sea. The relative 

 importance of dilution of the polluted water by sea water, of the death of 

 the coliform bacteria, of sedimentation and predation by animals has never 

 been clearly assessed in the marine environment. 



Our studies on this problem have included laboratory investigations of 

 the viability of Escherichia coli in sea water and surveys of some polluted 

 areas selected in the hope that the various factors in the disappearance of 

 pollution bacteria could be evaluated. The results described here must be 

 considered of a preliminary nature. 



The results of our laboratory investigations of the death rate of 

 Escherichia coli in sea water will be described first. Previous investigations 

 of this problem have given widely divergent results, varying from death 

 rates much more rapid than are found in fresh waters (Calif. State Dept. 

 Pub. Health 1943; Carpenter, Setter and Weinberg 1938; ZoBell 1936, 

 1946) to the conclusion that sea water is neither antiseptic nor inimical to 

 enteric bacteria (Dienert and Guillerd 1940). We have found that the 

 laboratory treatment of the sea water influences the results greatly. The 

 use of artificial, synthetic or diluted sea water cannot be expected to give 

 results which will correspond to the natural phenomenon. 



* Contribution No. 446 from the Woods Hole Oceanographic Institution. 



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