The Dinoflagellate Genera Brachidinium, Asterodinium, Microceratium and Karenia in the Open SE Pacific Ocean

doi:2006.21.4.445

Algae > Volume 21(4); 2006 > Article

Algae 2006;21(4): 445-452. doi: https://doi.org/10.4490/algae.2006.21.4.445

Fernando Gómez

Station Marine de Wimereux, Université des Sciences et Technologies de Lille, FRE 2816 ELICO CNRS, 28 avenue Foch, BP 80, F-62930 Wimereux, France

ABSTRACT

The morphometry and distribution of the unarmoured dinoflagellates Brachidinium capitatum F.J.R. Taylor, Asterodinium gracile Sournia, Microceratium orstomii Sournia and the toxic species Karenia papilionacea Haywood et Steidinger have been investigated in open waters of the SE Pacific Ocean. The genus Microceratium Sournia is recorded for the first time since the initial description. These taxa showed a high morphological similarity and they may correspond to life stages of a highly versatile single species that is able to project body extensions. Karenia papilionacea showed the higher abundance in the surface waters of the more productive areas (the Marquesas Archipelago and the Peru-Chile Current). Brachidinium capitatum and K. papilionacea often co-occurred, predominating B. capitatum in offshore surface waters. Asterodinium gracile was recorded at the bottom of the euphotic zone (down to 210 m depth), with a shallower distribution in more productive areas. Intermediate specimens of Asterodinium-Brachidinium-Karenia, with variable disposition and size of the body extensions were illustrated.

Key words: Asterodinium, Brachidinium, harmful algae bloom, Karenia papilionacea, Microceratium, phytoplankton, SE