The sea contains an extensive microbiological population in cluding bacteria, yeasts, molds, diatoms, dinoflagellates, protozoa, and other microscopic organisms. By virtue of their physiological activities such microorganisms, which vary greatly in diversity of form and in relative abundance, play an important role as bio chemical, geological, and hydrobiological agents in aquatic en vironments. Microbiology is thus a marine science co-ordinate with marine #botany, chemical oceanography, marine geology, physical oceanography, and marine zoology (1). Besides being concerned with the effects of microorganisms on the biological productivity of the sea, the transformation of organic matter, and the diagenesis of marine bottom deposits, the marine micro biologist is confronted by practical problems, e.g., problems of sanitary significance, such as fish spoilage (2, 3), shellfish pollu tion (4), the fouling of ships' bottoms (5), and deterioration of cordage (6), rubber (7), and wooden structures (8) exposed to water. This report is concerned primarily with the biochemical a ' ctivities of bacteria in the sea.
ABUNDANCE OF BACTERIA IN THE SEABacteria in sea water.-Comprehensive reviews by Benecke (11) and ZoBell (12) indicate that bacteria are widely distributed in the sea, although relatively less abundant than in soil or fresh water. The numbers of bacteria found in sea water, as determined by plating procedures, range from a very few cells to hundreds of thousands of cells per ml. (13). The largest bacterial populations generally occur in water near shore where there is much terrig-, cnous (land-born) pollution (14,15, 16).In the open ocean the abundance of bacteria increases from the surface downward to depths of forty or fifty meters and then de creases (17,18) until, at depths exceeding two hundred meters, there may be fewer than one viable cell per mt. (14). The bac terial population is not detectably restricted by the high hydro-1 Contribution from the Scripps Institution of Oceanography, New Series, No. 330. 565 Annu. Rev. Biochem. 1947.16:565-586. Downloaded from www.annualreviews.org Access provided by West Virginia University on 11/20/14. For personal use only. Quick links to online content Further ANNUAL REVIEWS