The observations of Issatchenko (1914), Benecke (1933), Waksman (1934), ZoBell (1938) and others have established that bacteria are quite widely distributed in the sea where they probably play an important role influencing chemical, physico-chemical, geological and biological processes. However, due primarily to the widely divergent analytical procedures which have been used by various investigators studying the distribution and activities of marine bacteria, the quantitative results obtained by different workers in different parts of the world are not comparable.