Bacterial 5′‐nucleotidase activity in estuarineand coastal marine waters: Role in phosphorus regeneration

Abstract

5′‐Nucleotidase (5PN) activity was measured with [γ‐32P]ATP, and related measurements were made by conventional techniques. Our results suggest that 5PN activity was more closely correlated with high algal and bacterial biomass and growth rates (eutrophic environments) than with phosphate depletion. 5PN was also potentially important in phosphate regeneration, even when dissolved nucleotide concentrations of a few nanomolar were assumed. If nuclease hydrolysis of dissolved nucleic acids also contributes to the dissolved nucleotide pool, then phosphate regeneration by 5PN activity would be significantly greater. In the high‐phosphate environments studied, most of the phosphate regenerated by 5PN was not taken up immediately.