SOME SOURCES OF ERROR IN THE ¹⁴C METHOD FOR ESTIMATING PRIMARY PRODUCTIVITY AND THEIR RELATIONSHIP TO LIGHT INTENSITY DURING INCUBATION ^{1, 2}

Abstract

Losses in primary productivity estimates caused by desiccation of filters ranged from 18 to 52% and were inversely related to the natural logarithms of light intensities during incubation. Losses caused by preservation were variable, depending on filter treatment and radioactivity counting method but were generally high in scintillation determinations. Significant fractions of total differences between primary productivity estimates from liquid scintillation counts of immediately filtered wet filters and Geiger-Müller counts of immediately filtered dry filters were associated with overestimating the relative activity of the carbon-14 stock solution (from 15 to 24%). In view of these and other causes for underestimating primary productivtiy, the ¹⁴C method requires further critical examination.