Inhibition of Primary Productivity through Heterotrophic Competition for Nitrate in a Stratified Estuary

Abstract

Virtual disappearance of NO₃ from Alberni Inlet brackish water containing very sparse phytoplankton with low growth rate was documented using ¹⁴C technique with chemical determinations of nutrients and chlorophyll. This phenomenon is explained by the enhancement of the heterotrophic biomass by the organic carbon-rich, nitrogen-deficient, pulpmill effluent and the consequent heterotrophic assimilation of NO₃ as a nitrogen source for protein synthesis.