ZoBell — 124 — Marine Microbiology 



hours at 7°C., and 30.7 hours at - 4 °C. These generation times indicate 

 a much more rapid rate of growth at the two lower temperatures than 

 has been reported for most non-marine bacteria. 



Additional literature on the temperature relations of marine bacteria 

 is given by Horowitz-Wlassowa and Grinberg (1933), ZoBell (1934), 

 and KiSER and Beckwith (1942). 



Attachment propensities : — The tendency of marine bacteria to grow 

 associated with solid surfaces is discussed on pages 56 and St,. This is 

 not a peculiarity of marine bacteria, since many microorganisms from 

 other habitats grow exclusively or preferentially attached to solid surfaces. 

 However, bacteria which live in extremely dilute nutrient solutions such as 

 sea water or the water of oligotrophic lakes appear to depend more upon 

 solid surfaces than do those which inhabit regions where there is more 

 nutrient material. It appears that a relatively large proportion of marine 

 bacteria have become adapted to the sessile manner of growth, due to the 

 paucity of nutrients in the liquid system and the greater concentration of 

 adsorbed food materials upon solid surfaces. 



Fifty of the 96 different cultures of marine bacteria examined by 

 ZoBell (19436) exhibited marked attachment propensities, and all of 

 them exhibited some tendency to attach to glass slides submerged in sea 

 water. Thirty of the cultures developed more rapidly on submerged 

 slides than in a free-floating condition in dilutely nutrient media. Many 

 species formed micro-colonies on submerged surfaces. Pseudomonas 

 coenobios, Ps. marinoglutinosus, Ps. membranula, Ps. membranoformis, Ps. 

 periphyta, Ps. sessilis, Ps. stereotropis, Vibrio phytoplanktis, V. halo- 

 planktis, Bacillus epiphyticus, Flavobacterium amocontactum, Micrococcus 

 sedentarius, M. sedimenteus, Achroniobacter stationis, A. aquamarinus, Bac- 

 terium sociovivum, and Bad. immotum are outstanding examples of attach- 

 ment bacteria listed by ZoBell and Upham (1944). Species of Gallionella, 

 Sideromonas, Siderocapsa, and Caulobacter grow almost exclusively on 

 submerged surfaces. This also applies to many genera of sulfur bacteria 

 and most representatives of the order Myxobacteriales. 



Bacterial genera represented in the sea : — Further details regarding 

 the characteristics of marine bacteria can be conveniently summarized by 

 listing all of the recognized genera of bacteria and indicating whether 

 species of each have been found in the sea. The genera are described in 

 Bergey's (1946) Manual of Determinative Bacteriology. The relative 

 frequency with which representatives of each genus have been observed 

 in the sea is indicated by plus (+) or minus (— ) signs in Table XXXIV. 



Table XXXIV. — Reported and/ or observed occurrence of genera of Schizomycetes 

 represented in the sea. (An "A" indicates that quite likely the observed species are 

 adventitious): — 



Order I. Eubacteriales 



Family Genus Occurrence 



in the sea 

 Sub-Order I. Eubacteriineae 



Nitrobacteriaceae Nitrosomonas +? 



Nitrosococctis — 



Nitrosospira — 



Nitrosocystis — 



Nitrosogloea — 



Nitrobacter +? 



Nitrocystis — 



Hydrogenomonas — 



Thiobacillus + 



