Studies on the Thermal Sensitivity of Marine Bacteria

ZoBell, 1938) on the occurrence and importance of bacteria in the sea in different parts of the world but, unfortunately, the methods of investigation used by various workers have been so widely divergent that neither the qualitative nor the quantitative results are comparable. One of the greatest variables is the tem-perature to which the bacteria have been subjected, although For-ster (1892), Drew (1910), Berkeley (1919), and others have emphasized the extreme thermal sensitivity of marine bacteria. In fact, due to a lack of appropriate refrigeration of water baths, incubators, and other facilities while working on a boat at sea, marine bacteria have been subjected to wide ranges of tempera-ture. This paper is concerned with the effect that this may have upon the life processes and death of the bacteria. Only those bacteria found in the sea which will grow in nutrient sea water media but not in corresponding freshwater media, or those which have been isolated from a marine environment at places remote from possibilities of terrigenous contamination, are regarded as marine species. This distinction is made to exclude bacteria of obviously terrestrial origin with which bays, estuaries and coastal waters are contaminated. While there may be an interchange of bacteria between the land and the sea (Burke, 1 Technical assistance in these studies was furnished by the personnel of the