Chapter X — 139 — Organic Matter 



requires the addition of available nitrogen. This observation of Waksman 

 and Carey (1935^) suggests that the bacterial population of the sea and 

 the decomposition of carbohydrates may be limited by the amount of 

 available nitrogen present. 



Although widely and abundantly distributed in the sea, splitters of 

 disaccharides such as sucrose, lactose, and maltose are fewer in numbers 

 of species than are the bacteria which decompose simple sugars. About a 

 third of the bacterial species isolated from marine materials hydrolyze 

 starch. Achromohacter thalassius, Actinomyces halotrichis, Act. niarino- 

 limosuSf Flavobacterium halohydrium, FL iieptunium, Pseudomonas pleo- 

 morpha, Vibrio marinopraesens, and V. ponticus are examples of amy- 

 lolytic organisms described by ZoBell and Upham (1944). Most of their 

 Bacillus species from the sea, none of their Micrococcus species, and very 

 few of their Pseudomonas or Vibrio species attacked starch. Fox (1934) 

 demonstrated the ability of 69 different species of marine bacteria, 3 

 molds, and 2 yeasts to hydrolyze amygdalin with the gradual production 

 of HCN. 



Several species of marine fungi studied by Barghoorn and Lender 

 (1944) utilized maltose, galactose, xylose, starch, cellulose, and pectin. 

 Growth of the fungi was most rapid in sea water agar enriched with either 

 cellulose, pectin, or starch. 



Mannite was attacked by many species of marine bacteria observed by 

 Enevoldsen (1927). While on the steamer Dana, he noted an increased 

 acidity in sea water samples treated with mannite, a carbohydrate-like 

 hexatomic alcohol which occurs in certain marine algae. Enevoldsen 

 believed that mannite could serve as a carbon source for marine bacteria 

 in their natural habitats. 



Only a specialized few marine microorganisms are endowed with the 

 ability to utilize cellulose, although such organisms may be demonstrated 

 in most 10- to loo-ml. samples of sea water and in nearly all one-gram 

 samples of bottom deposits. Using the minimum dilution method, 

 ZoBell (1938a) demonstrated 1000 cellulose digesters per gram of mud, 

 as compared with 100,000 glucose fermenters and 10,000 starch hy- 

 drolyzers. 



Cellulose-decomposing bacteria were found to be generally present in 

 sea water, and particularly abundant in bottom deposits and diatom tows, 

 by Waksman et al. (1933a) in the Gulf of Maine and George's Bank. 

 Species of Cytophaga, Cellvibrio, and Cellfalcicula were identified. In 

 crude cultures, the cellulose-decomposing bacteria were invariably accom- 

 panied by numerous protozoans, including flagellates, ciliates, and 

 amoebae, all of which feed upon bacteria. Most of the cellulose decom- 

 posers were aerobic, but anaerobic forms were also demonstrated. Some 

 of the latter produced gas. A variety of sugars were utilized by the cellu- 

 lose decomposers. Some of them decomposed agar and other hemicellu- 

 loses. 



Bavendamai (1932) found aerobic cellulose digesters in all marine 

 mud samples, and anaerobic cellulose digesters in many samples which 

 he examined. Many other workers refer to the occurrence of cellulose- 

 splitting bacteria in the sea, but no noteworthy quantitative studies have 

 been made on marine cellulose digesters. 



RuBENTSCHiK (19286) reported that aerobic cellulose digesters are 

 active in salt limans. He isolated Actinomyces melanogenes which decom- 

 posed paper. Later he (1933) found that anaerobic cellulose digesters are 



