Effects of 22‐µm screens on size‐frequency distributions of suspended particles and biomass estimates of phytoplankton size fractions1

Fractionation of whole water samples through 22‐µm mesh screens reduced the concentration of particles with mean spherical diameters (MSD) >10 µm. Fractionation did not affect particle concentrations <10 µm when nanoplankton dominated but resulted in an increase when net plankton dominated as a consequence of the breakup of chains. A 50% removal usually occurred at a MSD of 16 µm. Correlations between the chlorophyll a content and volume of size fractions were significant, and nanoplankton had more chlorophyll a per unit volume than net plankton.