A Comparison of Methods for the Estimation of Phytoplankton Primary Production

Abstract

AbstractThe primary productivity of phytoplankton in several lakes with different trophic status was estimated by radiocarbon and dissolved inorganic carbon (DIG). consumption methods. On an average, the direct DIC consumption method with light and dark bottles yielded 46% higher results than the radiocarbon method. The exact nature of the difference is obscure, but it is suggested that greater attention should be paid to heterotrophic consumption during the experiment than has been done in previous studies, as this is intimately linked with primary production.The liquid scintillation and Geiger Müller (GM). counts resulted in similar estimates of primary productivity when the radioactivity of the stock NaH14CO3‐solution for the GM method was determined by the biological method of Steemann Nielsen. This and the fairly close agreement of the results with those of the DIC consumption method indicate that the radiocarbon method is equally useful in estimating primary productivity in lakes ranging in status from oligotrophic to very eutrophic.