The Resistance of Organic Materials to Attack by Marine Bacteria at Low Temperatures

T h e interest of the Bell System in the extent of marine bacterial activity at great ocean depths stems from the knowledge t h a t certain organic materials are susceptible to attack by such organisms. For example, studies made by ZoBell and Beck with 1 on rubber products a n d by ZoBell 2 on hydrocarbons have indicated t h a t marine bacteria are capable of utilizing these materials. Therefore, one phase of a biological testing program (see Fig. 1) initiated by the Laboratories in 1954 has been designed to determine the resistance of organic materials that were possibly applicable in ocean cable construction to attack by both aerobic and anaerobic marine bacteria. T h e first d a t a collected from these laboratory tests have been reported earlier by Snoke, 3 and showed t h a t in m a n y instances specific organic materials were capable of being utilized by marine bacteria at 20°C. Attack was predominately by aerobes, little attack having occurred due to sulfate-reducing anaerobes. T h e 20°C temperature is representative of certain shallow water environments and is in the range which supports high microbial activity. Ocean bottom temperatures at depths greater than 1000 meters range from 5° to -- 1.5°C.4 T h e present work, concerned with deep water temperatures, involves the testing of the resistance of the materials to aerobic bacteria at an incubation temperature of .r)°C and the comparison of the results with those at 20°C. It was assumed initially t h a t the rate of activity would be somewhat lower at 5°C, and since, in most cases, there had been little attack by anaerobic organisms at 20°C, no 5°C anaerobic tests were conducted.