Picoplankton Growth Rates in Subtropical Hawaiian Embayments

Abstract

The size structure of phytoplankton biomass and productivity and the specific growth rates (m) of the picoplankton (i.e., < 3mm fraction) were examined in six Hawaiian embayments. The portion of total phytoplankton chlorophyll present in the < 10 mm and < 3 mm fractions ranged from 38 to 62 percent and 16 to 52 percent, respectively. Picoplankton accounted for between 34 and 63 percent of total community photosynthesis. Picoplankton growth rates ranged from 0.056 to 0.202/h (0.97 to 3.62 doublings/day). The rapid growth rates in these aquatic environments probably result from inputs of terrestrially derived nutrients; the m values for the picoplankton fraction are thought to represent upper limits for growth rates of the total population.