Mass balance of carbon and phosphorus in Shark Bay, Western Australia1

Deviations of total CO 2 , total alkalinity, and reactive P from conservative evaporation lines are used to quantify nonconservative fluxes of these materials in a negative estuary; the fluxes are then partitioned among CaCO 3 production, net community organic carbon production, and CO 2 gas evasion. The rate of organic metabolism for the system is controlled by nutrient delivery, although individual communities within the system support higher local metabolic rates than the bay‐wide average by exchange of materials between autotrophic and heterotrophic components. The three CO 2 flux processes act in concert to keep pH and P co 2 relatively constant.