Interestingly, the picophytoplankton were responsible for approximately 20–25% of carbon fixation in both bloom and non-bloom samples , though cyanobacteria were likely more important primary producers outside patches and while picoeukaryotes were likely larger contributors inside (Fig. 3). The high rates of carbon-specific primary production in the >20 mm size fraction and the high levels of dissolved oxygen within patch communities were consistent with what has been previously observed in Chesapeake Bay