Nitrifying bacteria (ammonia- and nitrite-oxidizers) were isolated from sea-surface films collected in the Gulf of California. Laboratory studies indicate substrate oxidation by these isolates is inhibited by light. Ammonia-oxidizers showed lower nitrifying activity and a longer lag time when held in an 8-hr light:16-hr dark regime compared to those held completely in the dark, and nitrite-oxidizers showed nitrifying activity only when held in the dark. Tracer studies using 15N-ammonia corroborate that little or no nitrification occurs in the surface films of subtropical seas.
Horrigan, S. G., A. F. Carlucci, and P. M. Williams. 1981. "Light inhibition of nitrification in sea-surface films." Journal of Marine Research 39, (3). https://elischolar.library.yale.edu/journal_of_marine_research/1559