PHOTOCHEMICAL PROCESSES IN THE INORGANIC NITROGEN CYCLE OF THE SEA1

There appears to be some confusion in the literature as to the role photochcmical proc-esses play in the nitrogen cycle. An attempt has been made to reevaluate the problem with regard to the sea. Test solutions of scawaters and distilled water enriched with nitrate, nitrite, and ammonia were exposed to sunlight while in open dishes and while immersed in the sea. In addition, experiments wcrc carriecl out using a fixed-wavelength ultraviolet source. It is concluded that the photooxiclation of ammonia is of no significance while the photo-reduction of nitrate is of possible but cloubtful significance. In general, it may bc con-cludcd that photochcmical proccsscs cxcrt an cxtremcly limited effect upon the nitrogen cycle of the sea