AME 33:303-308 (2003)  -  doi:10.3354/ame033303

ABSTRACT: Pfiesteria piscicida and Cryptoperidiniopsis spp. are common co-occurring heterotrophic dinoflagellates in estuaries along the Atlantic coast of the United States. We isolated P. piscicida, Cryptoperidiniopsis sp., and 2 benthic ciliates (Euplotes vannus and E. woodruffi) from North Inlet estuary, South Carolina, and examined the growth and grazing properties of the ciliates on cultures of the dinoflagellates maintained with cryptophyte (Storeatula major) prey. Ciliate growth and grazing parameters on cryptophyte monocultures and mixed diets of cryptophytes and P. piscicida were significantly higher with E. woodruffi than E. vannus. Also, the net grazing impact of E. woodruffi on P. piscicida prey was higher than the impact on Cryptoperidiniopsis sp., while the E. vannus grazing effect did not differ with dinoflagellate prey. The results indicate the potential for effective predatory control by euplotid ciliates on nontoxic P. piscicida and Cryptoperidiniopsis sp. under defined laboratory conditions.

KEY WORDS: Benthic ciliates · Cryptoperidiniopsis · Euplotes · Heterotrophic dinoflagellates · Microzooplankton grazing · Pfiesteria