August 2014

Photo of Noctiluca scintillans by Dr. Vera Trainer and Brian Bill, NOAA Photo of Noctiluca scintillans bloom

Photo of Noctiluca scintillans red bloom Photo of Noctiluca scintillans by Dr. Vera Trainer and Brian Bill, NOAA

Photo credit: top left and bottom right: Dr. Vera Trainer and Brian Bill, NOAA; top right: Teri King, Washington Sea Grant; bottom left: Dan Hanson, Hood Canal resident

Phytoplankton of the month — August 2014

Noctiluca scintillans

Noctiluca scintillans is an unarmoured dinoflagellate with cells ranging in size from 200 to 2,000 µm in diameter. Their cytoplasm may contain photosynthetic symbionts. Since chloroplasts are absent in Noctiluca, they obtain their food by engulfing prey items (phagotrophy) that include diatoms, other dinoflagellates, ciliates, and fish eggs. A tentacle on the organism helps capture the prey.

Noctiluca's distribution is neritic and cosmopolitan in cold and temperate waters. They may form extensive tomato soup colored blooms during the warm calm summer months. Noctiluca, which means "night light," often produces a brilliant display of bioluminescence when the water is disturbed at night. Because it is very buoyant, it is frequently blown into windrows on the water or into bands of orange-red scum along the shore. It has been reported that large blooms may produce high levels of ammonium that could be toxic to fish.

For more information on Noctiluca see: A Taxonomic Guide to Some Common Marine Phytoplankton, by Rita Horner (Biopress Ltd. 2002)

SoundToxins, a diverse partnership of Washington state shellfish and finfish growers, environmental learning centers, Native tribes, and Puget Sound volunteers, is a monitoring program designed to provide early warning of harmful algal blooms and Vibrio parahaemolyticus events in order to minimize both human health risks and economic losses to Puget Sound fisheries.

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