Dinoflagellate Cysts Within Sediment Collections From the Southern Chesapeake Bay, and Tidal Regions of the James, York, and Rappahannock Rivers, Virginia

The upper 2 cm of sediment core samples from 70 stations in the tidal waters of three Virginia rivers and at 23 stations in the lower Chesapeake Bay were sampled for dinoflagellate cysts. The river sediment cysts were dominated by three common bloom producing species (Heterocapsa triquetra, Scrippsiella trochoidea, and Cochlodinium polykrikoides ), whereas these were in low concentration in the Chesapeake Bay sediments which contained mainly dinoflagellate cysts of neritic and oceanic taxa. The mean sediment concentrations from stations in the James, York, and Rappahannock rivers were respectively 1174.8, 536.2, and 323.6 cysts g1. The mean cyst concentration in the Chesapeake Bay sediment was 714. 8 t 1. Cysts of 2 potentially harmful species were recorded from the sediment, with the river sediments identified as seed beds and a source for re-occurring algal blooms in