Red tide in the upwelling region of Baja California1

Abstract

Predominant organisms in a red water dinoflagellate bloom during the seasonal onset of coastal upwelling off Baja California were Gonyaulax polyedra, Ceratium furca, and Gymnodinium sp. The major part of the chlorophyll and the ¹⁴C assimilation in the area was related to the G. polyedra population. The maximum concentration of these organisms was associated with low salinity water of the surface California Current. The dinoflagellates remained in the area during the 20‐day cruise, although the vertical stability coefficient was low, with no steep temperature gradient. The high concentrations of small copepods suggest them as major grazers of G. polyedra.