Compartmental models of nitrogen cycling in tropical and temperate marine environments

Abstract

Time-course measurements of super(15)N tracer kinetics in particulate organic and in NH super(+) sub(4) pools from tropical and temperate regions were used to test several compartmental models describing the exchange of super(15)N tracer in microplankton communities. Several lines of evidence suggested the involvement of a third, dissolved pool, arbitrarily labelled dissolved organic nitrogen (DON). Although the kinetic patterns of tracer movement were different between the tropical stations and the temperate one, the same 3-compartmental model in which PON and DON can exchange material only through the intermediate of NH super(+) sub(4) gave the best fit. Only the transfer coefficients were modified. Results show that compartmental analysis is useful for the estimation of compartmental transfer rates and for testing the assumptions implicit in any given model.