Aquatic Sciences Meeting, Albuquerque 2001

SS13 Mixotrophic Plankton - Combining Phototrophic and Heterotrophic Nutrition

Date: Friday, February 16, 2001, Time: 10:45:00 AM

Location: Acoma/Zuni/Tesuque

Adolf, J, E, University of Maryland Horn Point Lab, Cambridge, USA, jadolf@hpl.umces.edu

Place, A, R, University of Maryland Center of Marine Biotechnology, Baltimore, USA, place@umbi.umd.edu

Stoecker, D, K, University of Maryland Horn Point Lab, Cambridge, USA, stoecker@hpl.umces.edu

Harding, L, W, University of Maryland Horn Point Lab, Cambridge, USA, larry@kestrel.umd.edu

GYRODINIUM GALATHEANUM (DINOPHYCEAE)IN SEMI-CONTINUOUS BATCH CULTURE: PHYSIOLOGICAL STUDIES OF A PHAGOTROPHIC PHOTOTROPH

Gyrodinium galatheanum (Dinophyceae) was grown in semi-continuous batch culture under phototrophic and mixotrophic conditions. Storeatula major (Cryptophyceae) was maintained under similar culture conditions and used as prey in the mixotrophic culture. The goal of maintaining semi-continuous batch cultures was to allow physiological measurements to be made on the mixotrophic dinoflagellate without interference from the prey cryptophyte. Cultures were maintained at saturating irradiance (200 micrmole photons m-2 s-1, 12:12 L:D), 20 deg C, in f/2 -Si media with P at f/20 concentration. Phototrophic G. galatheanum grew at 0.30 d-1 (s.d.= 0.110), mixotrophic G. galatheanum grew at 0.52 d-1 (s.d.=0.056), and S. major grew at 0.93 d-1 (s.d.=0.075). The grazing rate of the mixotrophic culture was estimated at 2.2 prey predator-1 d-1. Mixotrophic cultures were nearly depleted of free cryptophytes 24 h after each initial feeding. Measurements of the photophysiological state and biochemical composition of the cells were made at this time point. Advantages and disadvantages of using this technique to study the physiology of mixotrophic growth will be discussed.

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Aquatic Sciences Meeting, Albuquerque 2001

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