Aquatic Sciences Meeting, Albuquerque 2001

PC01 Harmful Algal Blooms

Date: Tuesday, February 13, 2001

Location: Southwest Hall

Park, M, G, Smithsonian Environmental Research Center, Edgewater, USA, park@serc.si.edu

Coats, D, W, Smithsonian Environmental Research Center, Edgewater, USA, coats@serc.si.edu

EFFECTS OF THREE STRAINS OF THE PARASITIC DINOFLAGELLATE AMOEBOPHRYA ON PHOTOSYNTHESIS, LIGHT ABSORPTION, AND QUANTUM YIELD OF DINOFLAGELLATE HOSTS

Despite growing reports on parasites of dinoflagellates, little is known about the ecophysiological and bio-optical impacts on hosts after infection. We examined effects of parasitism on photosynthesis, light absorption, and quantum yield of the photosynthetic dinoflagellates Gymnodinium sanguineum, Gyrodinium galatheanum, and Gyro. instriatum in a light:dark cycle of 14:10 h. Uninfected Gym. sanguineum and Gyro. instriatum showed strong diel periodicity in photosynthesis, whereas infected hosts showed a distinctly different pattern. Infected Gym. sanguineum lost the diel periodicity immediately after infection, but infected Gyro. instriatum continued to show a periodicity that was less pronounced than uninfected hosts. This difference was associated with different sites of infection in Gym. sanguineum (nucleus) and Gyro. instriatum (cytoplasm). The shape of the light absorption spectrum of dinospores (free living stage of the parasites) resembled that of detritus, with light absorption being negligible compared to that of host cells. However, Amoebophrya caused light absorption by hosts to increase over the infection cycle, particularly in the blue wavelength. Other effects of parasitism on photosynthetic parameters and optical properties of dinoflagellate hosts will be discussed.

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Aquatic Sciences Meeting, Albuquerque 2001

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