ZoBell — 128 — Marine Microbiology 



The number of plus signs in the table indicates the relative abundance 

 of the genus as judged from reports in the literature and our own observa- 

 tions. The plus signs do not indicate the relative numbers of species of 

 each genus, since in many cases the species are not known. There may be 

 only one marine species of Desulfovibrio, for example, but since it appears 

 to be widely and abundantly distributed in the sea, particularly in bottom 

 deposits, it is scored two-plus (++). On the other hand, there may be 

 several marine species of Staphylococci or Actinomyces but since the pres- 

 ence of representatives of these genera have been only infrequently re- 

 ported, they are scored one-plus (+). Representatives of all orders have 

 been found living in the sea. 



Attention is directed to the actinomycetes, which, because of the mold- 

 like appearance of certain genera, are often not regarded as bacteria. 

 Though not true bacteria, the actinomycetes belong to an order of Schiz- 

 omycetes, the Actinomycetales. Species of Actinomyces have been found 

 growing on dead marine algae, on submerged surfaces where organic mat- 

 ter has accumulated, and in bottom deposits. ZoBell and Upham 

 (1944) described two new species, Actinomyces marinolimosus and Act, 

 halotrichis. Species of Mycobacterium, Nocardia (Proactinomyces) , and 

 Micromonospora have been observed in sea-water enrichment cultures 

 growing on petroleum hydrocarbons (ZoBell et al., 1943) and rubber 

 products (ZoBell and Beckwith, 1944). They appear to be widely dis- 

 tributed in the sea. 



There are nearly as many known marine species of the order Spiro- 

 chaetales as those reported from non-marine habitats, notwithstanding 

 the fact that the sea has not been extensively explored by bacteriologists. 

 Spirochaeta plicatilis, which Ehrenberg (1838) found in sea water, has 

 the distinction of being the first accurately described bacterium. Spiro- 

 chaeta marina and probably Sp. eurystrepla live in the sea. Species of 

 Saprospira and Cristospira have been found almost exclusively in shell- 

 fish (see p. 187). The observations of Zuelzer (1928) suggest that 

 Leptospira bijiexa occurs in the sea. 



