entry of microorganisms and proteins from the ocean. Because of the 

 possibility that the dialyzer bags might rupture, pliable, translucent, 

 polyethylene bottles were also employed as containers for some of the E. 

 coli cultures. Although the bottles were essentially impermeable, they 

 did permit the cultures to be exposed to ocean pressures and temperatures. 



Synthetic sewage water was prepared for the experiment by adding 

 approximately 10 grams (wet weight) of human feces to a 2-liter flask 

 of seawater. The flask was autoclaved for 20 minutes at 15-psi steam 

 pressure. A 2-liter flask of filtered seawater was autoclaved at the 

 same time. Both flasks were inoculated with E^ coli in the usual 

 manner. Two of the BACT-CHEK discs were used in the preparation of each 

 of the two cultures. 



Some of the seawater culture was distributed into the dialyzer bags 

 and some into 25-ml polyethylene bottles. The synthetic sewage culture 

 was distributed only into the polyethylene bottles. 



The dialyzer bags and the 25-ml polyethylene bottles containing the 

 E. coli cultures were placed in wide-mouthed, 500-ml polyethylene bottles 

 in which numerous 1/4-inch round ventilation holes had been drilled. The 

 larger bottles served as cages for uhe smaller containers. They were 

 securely fastened to the anchored nylon line and suspended at various 

 depths in the ocean. 



Bacterial counts were made after various time intervals. Counts 

 were also made on the remains of the original cultures which were 

 maintained in the laboratory at room temperature. The results of the 

 experiment are summarized in Table 1 . 



Effect of Sunlight on the Survival of E^ coli 



An investigation was made of the effect of sunlight on the survival 

 of E. coli. Cultures of the microorganisms were exposed in opaque and 

 in translucent containers at the ocean surface and at depths of 200 and 

 1,000 feet. Comparisons were then made of the numbers of microorganisms 

 surviving in the opaque and translucent containers. The experiment was 

 conducted in the following manner. 



A culture containing 100,000 E^ coli per ml was distributed into 54 

 dialyzer bags with a capacity of approximately 25 ml each. Six of the 

 bags were retained in the dark in the laboratory for control tests, 

 three being maintained at room temperature and three at 3 C. The other 

 48 bags were divided into pairs and distributed into 24 cages made of 

 polyethylene bottles in which numerous 1/4-inch round ventilation holes 

 had been drilled. Twelve of the cages had been made opaque by a covering 

 of electrician's black tape; the other twelve remained translucent 

 (Figure 8). 



The following day, two of the opaque cages and two of the translucent 

 cages containing dialyzer bags of E. coli culture were exposed near the 

 ocean surface for periods of 1 and 4 hours. The exposures were made by 

 simply fastening the cages on the end of a length of nylon parachute 

 cord and lowering them over the side of the ship. The bottles floated 

 and remained on the surface. The third of the opaque and the third of 

 the translucent cages were not exposed in the ocean and were employed as 

 zero hour controls. 



