Recovery of nitrification in marine bacteria following exposure to carbon monoxide or light

Abstract

Recovery of activity by 2 marine nitrifying bacteria, Nitrosomonas cryotolerans and Nitrobacter sp. Nb297, was monitored after exposure to light and/or carbon monoxide. N. cryotolerans recovered more rapidly after exposure to artificial light (25 W m-') than CO (11.4 PM). The adhtion of 100 yM NH,+ during the time of light or CO exposure allowed the cells to recover faster and decreased the difference observed between the inhibitory effects of light and CO. Cells exposed to sunlight recovered much illore slowly than cells exposed to either CO or artificial hght. The ammonium oxidizer N. cryotolerans when exposed to sunlight (2 h) recovered up to 35 "/o of its original ammonium oxidizing activity. Recovery increased to 57 % in the presence of additional substrate (100 pM NH,'). The nitrite oxidizer Nitrobactersp. Nb297 did not show a noticeable recovery from sunlight whether substrate was added or not. O Inter-ResearcWPrinted in F. R. Germany