298 Marine Microbiology 



Some organisms seem from laboratory experiments to be 

 suited to life in the sea, yet because a required type of nutrient 

 is lacking there, they occur instead in habitats which are really 

 sub-optimal for salinity. In a different direction, several Alter- 

 naria from the sea (25-30 S/^t) seem from laboratory data to 

 be essentially terrestrial, yet because dead wood lies in littoral 

 waters, they will live on it and tolerate supra-optimal salinity 

 conditions. A number of hyphomycetous genera have been tested 

 in tliis laboratory for their ability to grow in salt media, and more 

 than half of them suffer from any increase in salinity at any tem- 

 perature, even though they tolerate full strength sea water. If 

 they were not cultivated on a variety of media, one might think 

 them natural marine forms. 



Organisms which have shown the Phoma pattern are eury- 

 haline, or facultative osmophiles, and are not necessarily either 

 terrestrial or marine. At temperatures up to the apparent optimum 

 for the nutrient conditions obtaining, they grow well in solutions 

 supplying 1 to 25 Atm osmotic pressure, i.e. to 30 S%c: but at 

 supraoptimal temperatures, they require ever higher salinities. 



SUMMARY 



The imperfect fungus, Zalerion eistla, from the Atlantic wa- 

 ters of Newfoundland grew better at higlier temperatures when 

 supplied with increased sea water content in the medium but 

 not with NaCl. The organism was incubated over a wide range 

 of temperatures on a number of media which were made up 

 with graded concentrations of osmotically active compounds: 

 single salts, as calcium or sodium chloride, metabolizable sugars, 

 and non-metabolizable alcohols, as glycerol and pentaerythritol. 

 The concentrations of the active substances were prepared so 

 as to provide similar osmotic pressures in each series. The in- 

 terrelation between temperature and salinity appears to be more 

 a matter of osmotic pressure of the surrounding medium than of 

 the type of nutrition. Growth ciuves from tlie different nms were 

 similar, whether the osmotically active materials were ionic or 

 not, metabolizable or not, penetrable or not. If the nutrient con- 

 centration of the medium was reduced to a subsistence level, the 



