A Phaeocystis globosa bloom associated with upwelling in the subtropical South Atlantic Bight

We observed an unusual, subtropical blown of Phaeocystis globosa Scherffel during a strong up-welling event and confirmed its identity using morphological, physiological and genetic traits. This low-latitude bloom of P globosa colonies occurred on the South Atlantic Bight, continental shelf during the summer of 2003. Maximum chlorophyll a concentration measured during this subsurface bloom was 11.37 mu g L(-1) at 31 in depth. Divers reported abundant flocculent material below the sleep thermocline, and this material was identified as Phaeocystis sp. using microscopy Using morphological and physiological traits as well as the sequence of the 18S small subunit ribosomal RNA gene (GenBank Accession # EF100712), this phytoplankton was identified as P. globosa. Interactions of physical and biological conditions may restrict low-latitude P. globosa blooms to strong up-welling events.