ZoBell and Morita found millions of viable bacteria per gram of sediments 

 taken from depths exceeding 33,000 feet on the Danish Galathea Deep-Seo 

 Expedition. '^ AAcny deep-sea species are able to grow well at a temperature as 

 low as centrigrade. The high hydrostatic pressures which prevail at great depths 

 are not a deterrent to bacterial life; ZoBell found that some bacteria are actually 

 barophillic or pressure-loving bacteria and reproduced only when subjected to 400 

 to 1,000 atmospheres. ^^ (See Figure 1 for method of converting atmospheres to 

 pounds per square inch.) 



Because marine bacteria are able to live in various marine environments and 

 can utilize various materials for growth, they are one of the major biological agents 

 of deterioration and fouling of various organic and inorganic materials and equipment 

 in sea water and in marine sediments. Marine bacteria play an important role in the 

 fouling of submerged surfaces by (1) affording a foothold for other animals, (2) dis- 

 coloring glazed or bright surfaces, (3) becoming a source of food for barnacles, etc., 

 and (4) promoting the deposition of the carcareous cements of sessile animals. '^ 

 The effect of fouling by marine organisms (including the bacteria) on the acoustic 

 efficiency of submerged sonar equipment is extremely serious, resulting in an average 

 attenuation of about three decibels per inch of fouling thickness. 



Pits between 10 and 37 mils in depth were formed beneath the growth of fouling 

 organisms (barnacles) on the surface of monel metal immersed in sea water at 

 Port Hueneme, California. These pits may have resulted from localized oxygen- 

 concentration ceils due to barnacle growth. Bacterial film (produced as a result 

 of abundant bacterial growth) may form a protective layer over an antifouling 

 coating normally toxic to fouling animals, thereby affording these animals a foothold 

 for growth. '^ it may be possible that a simple rapid test to determine the effective- 

 ness of antifouling paints can be developed by testing antifouling paint against marine 

 microorganisms. 



Marine ceiluiose-decomposing bacteria are responsible for millions of dollars 

 worth of damage to fiber nets, seines, and lines used by commercial fishermen. The 

 average useful life of this equipment is less than two years. '^ Manila ropes and 

 cotton fishing nets have been destroyed after 14 months in sea water. Also present 

 in the sea are cellulose-destroying fungi found infesting natural fibers and wood. ^"' '' 

 Rubber products including rubber hoses, chlorinated rubber paints, rubber gaskets 

 and similar materials used at sea, either submerged or subject to frequent wetting with 

 salt water, are decomposed by the action of marine bacteria. Rubber is generally 

 regarded as biologically inert, but highly purified rubber, both natural and synthetic, 

 as well as various rubber products are susceptible to bacterial oxidation in the presence 

 of mineral and moisture. Corks used at sea as floats by commercial fishermen and 

 others also are decomposed by marine bacteria, which slowly destroy the buoyancy 



