Chapter 39 



Researches on Nitrifying Bacteria in Ocean 

 Depths on the Coast of Algeria 



HuGUETTE Vargues and Jean Brisou 



iSiiice the discoveries of Schloesing and Mimtz and of Wino- 

 gradsky, many investigations have been dedicated to the phenom- 

 ena of nitrification; the mechanism of the oxidation of ammonium 

 salts. From an ecological standpoint, nitrification in the marine 

 environment has not failed to draw the attention of investigators, 

 but the results obtained are quite divergent. The authors gen- 

 erally agree in recognizing that nitrifying bacteria do not exist 

 in the water itself, but only in the sediment deposits. Brandt (1) 

 notes their presence in the ooze of the Kiel sound, while Gran 



(3) finds none in the sediments of Norwegian fjords. Issatchenko 



(4) has obtained positive results with sediments from the Mur- 

 mansk area, Thomsen (5) also found these bacteria in the ooze 

 of the Kiel sound, the gulf of Naples and the Helgoland area. 



From 1952 to 1958, we had the opportunity to study samples 

 of marine muds and littoral sands from the depths of the Algerian 

 area, and the results of these studies concerning nitrifying bac- 

 teria are reported here. 



METHOD 



Samples were moculated into a medium containing a source 

 of ammonia nitrogen. We have adopted Omeliansky's medium: 

 SO4(NH0:1.3%; KH.PO,:1.0%; MG SO4:0.5%: ferrous sulfate: 

 trace. In this selective medium, the appearance of nitrites and 

 nitrates, and the release of nitrous or nitric nitrogen is investigated 

 with the aid of chemical titrations at regular interxals of time. 



This sensitive technique offers the advantage of a quantita- 

 tive evaluation of the nitrifying acti\ity in the marine muds. 

 However, it does not permit the distinction of the bacteria re- 



415 



