Inter-Research
Aquatic Microbial Ecology

ABSTRACT: Cysts of an oligotrich ciliate were isolated from sediment samples collected in Onagawa Bay on the northeastern Pacific coast of Japan and incubated under laboratory culture conditions. Successful excystment occurred regularly and the excysted cells were identified as Strombidium conicum. The cyst of S. conicum has a papulifères form and is enveloped by a double-layered wall, rigid inner and membranous outer layers. The excysted cells showed a distinctive conical shape with well-developed trichites and a ventral kinety restricted to the posterior end. The effects on excystment of temperature, light intensity, oxygen concentration, bacteria, and storage in the dark and at cold temperatures are reported. Among these variables, temperature is likely to be the principal factor controlling excystment.

KEY WORDS: Cyst . Excystment . Planktonic ciliate . Strombidium conicum

Published in AME Vol. 9, No. 2 (1995) on August 31
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1995