Carbon‐14 Uptake by Picoplankton and Total Phytoplankton in Eight New Zealand Lakes

Eight New Zealand lakes were surveyed for 14C uptake by phytoplankton as a function of light intensity. The results support the view that the photosynthetic picoplankton is an important contributor to primary productivity in oligotrophic lakes but is relatively unimportant in more eutrophic lakes. A comparison of carbon uptake vs. light intensity characteristics (P vs. I) of the picoplankton size class vs. that of the total phytoplankton community supports the view that the picoplankton size class may be adapted to utilization of dimmer light.