Home / Raphids / Heterosigma
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Name derivation:
Hetero- other; -sigma the letter 'S-shaped'. Probably incorrect.
Classification:
Chattonella B.Biecheler 1936; 3 of 13 species descriptions are currently accepted taxonomically (guiry and Guiry 2013). Order Chattonellales; family Chattonellaceae
Morphology:
Motile cells with two flagella approximately as long as the cell itself. Cells have a convex dorsal surface and a flattened ventral surface. Fibrocapsa is in the "golden-brown" line of raphids.
Similar Genera:
Habitat:
Marine, euryhaline. Capable of developing thin-layer populations at depth in 16 - 26 ppt salinity, as well as upward migration in much lower salinity (<8 ppt)(Bearon et al. 2006).
Toxicity:
Heterosigma akashiwo forms blooms toxic to fish (piscitoxins) in temperate marine waters globally (Bearon et al. 2006). In summer 2006, a bloom of Heterosigma akashiwo, released toxins that killed thousands of fish in the Strait of Juan de Fuca and in Puget Sound, Washington, USA. An aerial photo shows the bloom as a large dark "tongue" of water near Anacortes. In July 2006, the "bloom exploded within 24 hours," with no early indication, according to Kevin Bright of American Gold Seafoods, Anacortes, Wash., whose company suffered a considerable loss from the event (Sodt 2010).
References:
Bearon, R.N., D. Grünbaum, and R.A. Cattolico 2006. Effects of salinity structure on swimming behavior and harmful algal bloom formation in Heterosigma akashiwo, a toxic raphidophyte. Marine Ecology Progress Series 306:153-163. Graham L. and Wilcox L. 2000. Algae. Prentice-Hall Guiry, M.D. and G.M. Guiry 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 10 September 2013. Sodt, R. 2010. Northwest Scientists Study Toxins in Puget Sound’s Algal Bloom. Northwest Science & Technology, Spring 2010, Environment online.