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An Epibiont on the Red-Water Ciliate Mesodinium Rubrum

Published online by Cambridge University Press:  11 May 2009

David W. Crawford
Affiliation:
Department of Oceanography, The University, Southampton, SOI 5NH. Present address: University Marine Biological Station, Millport, Isle of Cumbrae, KA28 OEG

Extract

Spherical, opaque bodies (5–10 µm diameter) were frequently observed adhering to cells of the marine ciliate Mesodinium rubrum, particularly towards the end of red-water blooms in Southampton Water. Transmission electron microscope sections revealed these structures to be of biogenic origin, and packed with an amorphous, lipid-like material. No diagnostic features were observed to confirm their identity.

The phototrophic ciliate Mesodinium rubrum (Lohmann) forms recurrent red-tides each summer and autumn in the Southampton Water estuary, UK (Williams, 1980; Soulsby et al., 1984). During a study of the impact of these blooms on the estuary, live cells were routinely observed microscopically. Frequently, but predominantly later in the bloom, numerous individuals posessed spherical, colourless, but opaque bodies, apparently attached or adherent to the outer cell membrane. Cells observed prior to the bloom, or at other times of the year, were never observed o possess such structures.

Cells bearing these bodies were photographed live, or after preservation in Lugol's iodine, using the phase contrast optics of an Olympus BH2 photomicroscope.

Type
Short Communications
Copyright
Copyright © Marine Biological Association of the United Kingdom 1992

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