Habitat and Ecological Observations on Gymnodinium Acidotum Nygaard, a Colorless Dinoflagellate Phagocytizing Blue-Green Cryptophytes

Date of Graduation

Summer 1990

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Russell Rhodes

Abstract

A bloom of Gymnodinium acidotum, a rare dinoflagellate harboring a cryptomonad endosymbiont, was implicated in a fish kill in open waters of Stockton Lake, MO. In 1987. Collections from 1989 have shown that G. acidotum is normally associated with Spirogyra sp. in the benthos of shallow marshy areas frequented by waterfowl. Morphology and pigmentation vary in the natural environment according to water chemistry and the presence of cryptophytes. A short colorless phase, observed in vitro, consists of mononucleate cells that exhibit a phototactic circadian rhythm. Observations of colorless cells of G. acidotum cultured with Chroomonas sp. indicate that phagocytotic uptake, a short retention period, and digestion of the cryptophyte occurs. The evolutionary status of the G. acidotum/cryptophyte relationship is discussed in the context of the Serial Endosymbiosis Theory of organelle evolution.

Subject Categories

Biology

Copyright

© Stephen D Fields

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Dissertation/Thesis

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