Over 99% of the total nitrogen and phosphorus consumed each year by oceanic primary producers is ultimately supplied by regeneration. Phosphorus metabolism is particularly dependent on rapid regeneration of orthophosphate, since there is no biological phosphorus input process analogous to nitrogen fixation. Also, phosphorus regeneration (unlike nitrogen regeneration) is largely an extracellular process. An investigation of the role of microbial cell-surface enzymes in the regulation of Pi regeneration will be undertaken in the laboratory. Pure cultures of marine bacteria will be used to distinguish two enzymes, 5'-nucleotidase and alkaline phosphatase, on the basis of substrate specificity and the effect of phosphorus concentration. An attempt will be made to seperate and purify these two enzymes using gel electrophoresis. These studies should help clarify the potential importance of these two microbial enzymes in phosphorus regeneration and orthophosphate cycling, and set the stage for future use of molecular techniques.
