Denitrification as influenced by photosynthetic oxygen production.

An attempt was made to detect interaction between photosynthesizing algae and denitrifying bacteria by cultivating Chlorella sp. with Pseudomonas s t u t d . Denitrification was inhibited by illumination of the mixed culture after a dark period of 3 hr. It is suggested that immediate inhibition is due to the molecular oxygen produced by the suspended algae and distributed homogeneously in the culture. A delay of this inhibition may be caused by uptake of oxygen by the denitrifiers at a more rapid rate than its production by the algae. Thus, the quantitative aspects of this interaction depend upon the particular conditions of cultivation used. The ecological implications are discussed.