Periphytic Habits of Some Marine Bacteria

Abstract

In studying the factors which influence the increased bacterial activity during the storage of samples of sea water collected for bacteriological analysis, ZoBell and Anderson noted that multiplication occurs more rapidly in small volumes than in large volumes of the water. Similar observations were made on fresh water by Whipple who reported that after 24 hours' storage there were 300 bacteria per cc. in a gallon, 7,020 per cc. in a pint and 41,400 per cc. in 2 ounces of water which initially contained 77 bacteria per cc. Whipple attributed the difference to the oxygen content of the water, but in sealed receptacles ZoBell and Anderson found that oxygen was not the controlling factor. They noted a direct relationship between the area of solid surface exposed to the stored water and the bacterial activity in it. In continuing these studies, freshly collected sea water was filtered by gravity through a Buchner 4G sintered-glass filter into a 50-liter bottle. After shaking the bottle to mix the water and to insure its complete oxygenation, the water was siphoned into glass-stoppered bottles varying in capacity from 10 cc. to 10,000 cc., which were stored in a waterbath at 16°C. The bacterial population was determined immediately and at 24-hour intervals thereafter by plating procedures. The oxygen-content was estimated by the Winkler method on duplicate bottles of water. Representative findings are summarized in Table I which gives the maximal bacterial population found in each volume of stored water and the oxygen-content after 20 days' storage. The data in Table I show that the greatest consumption of oxygen occurs in the smallest volumes of stored sea water in which are also found the most bacteria.