Autotrophic Nitrification in the Ocean 



77 



10 15 20 25 30 



OArS AFTER COLLECTION 



Fig. 1. Increase of nitrites and nitrates in slope water enriched with am- 

 monia. 



media for growth of marine nitrifying bacteria. Generation time 

 for terrestrial nitrifying bacteria was less than twenty-four hours 

 and cell concentrations reached 2 X 10^ cells/ml. Marine nitrify- 

 ing bacteria grown in similar media without CaCO.! had a gen- 

 eration time of twelve da\s and cell density never exceeded 

 2 X 1()7- in the presence of CaCO:i generation time, as judged 

 from the increase of nitrite or nitrate, was shortened to two days. 

 An attempt was made to grow both terrestrial and marine 



