Potential for Long-Term Persistence of the Red Tide Dinoflagellate 'Ptychodiscus brevis' in North Carolina Coastal Waters

摘要

In October of 1987, the toxic red tide dinoflagellate Ptychodiscus brevis which normally resides along the Florida coast was introduced into North Carolina waters via the intrusion of a Gulf Stream eddy. The transported population resulted in the closure of shellfish beds in North Carolina due to the presence of brevetoxin in the shellfish. A major field effort was undertaken in February 1988 to determine the extent of the organism distribution. Benthic samples were collected as well as water column samples and were incubated in the laboratory for a one month period to determine the presence of cysts. Incubation of the sediment samples yielded no motile population which suggests that Ptychodiscus did not form a resting stage in North Carolina waters. Without further study, however, one cannot rule out the possibility that Ptychodiscus formed a resting stage, but its obligate period of dormancy was not complete during the short one month incubation.