Variations in the progress of 14C uptake as a source of error in estimates of primary production

The progress curves of 14C retention for samples of phytoplankton from the Irish Sea incubated at contrasting light intensities have been obtained by two methods. The first method (A) involved the incubation of the samples for various periods up to 6 h, while the second method (B) consisted of making a series of short-term incubations over the same 6 h period. Over this period, the cumulative uptake was generally less when estimated by method A than by method B. The difference was greater in the samples incubated at the lower light intensity, the light history of the samples having no effect on the difference. The differences had a kinetic basis, with two combinations of progress curves obtained by use of the two methods. (orig./AJ)