The microplankton community outside of dense C. polykrikoides bloom patches varied but was generally dominated by dinoflagel-lates and small, autotrophic nanoflagellates (Table 2). Average C.polykrikoides densities were 3932 1331 and 142 63.5 cells mL1 141G, 313B and 260B were observed only in the >5 mm size fraction of the non-bloom samples, while in both size fractions TRFs 324B was only detected in the bloom (Fig. 5C and D). In addition, the abundance of T-RFs 293B, and 52G were significantly (p < 0.05) higher in the18S total size fraction of non-bloom samples compared to the bloom samples.