Spatial and Temporal Variability of Dinoflagellate Cyst Abundance in a Tidal Estuary

A study of dinoflagellate cysts was made in an estuary near Plymouth, England for 1 yr. The data show that the cysts were most concentrated in sediments near the entrance of the estuary (3000 cysts (mL∙flocculant−1)) and less concentrated upstream (< 500 cysts (mL∙flocculant−1)). Dinoflagellate cysts were observed in 99% of the plankton samples with an average concentration of 9.2 cysts∙L−1. Thirty percent of the variance in planktonic cyst concentration was associated with tidal range, wind stress, and river flow. The potential for inoculation of nearshore dinoflagellate populations by estuarine populations is discussed.Key words: benthic resting cyst, dinoflagellate, estuary, frontal convergence, sediment trap, spring tides, turbulence