Effect of Controlled Pressure Changes on the Stimulation of Bioluminescence in Pyrocystis Lunula

摘要

Bioluminescence in a dinoflagellate species, Pyrocystis lunula, was stimulated by controlled, repeated pressure changes. Pressure pulses of a two-second duration were used to determine their effect on stimulated bioluminescene. Observations of organism sensitivity in response to the circadian rhythm, light phase, and cell fatigue were also made. The pressure change was affected by valve-regulated compressed air. The luminescence was detected with a photomultiplier tube. The mean threshold for luminescence in Pyrocystis lunula was found to be 5.10 + or - 1.70 psi. Pressure decreases were found to be much more effective than pressure increases. Three other rates of pressure change were investigated and a rough correlation was established between higher rates of pressure change and slightly lower threshold levels. Qualitative observations indicated that increased rates of pressure change were also associated with higher initial flashes and faster fatigue times. Pulse length appeared not to affect the stimulable luminescence to any significant degree. Measurements made at various times in the scotophase revealed a relatively constant, high level of light output, while only minimal, if any, light ouput was detected in the photophase. The resulting threshold level was applied to a pressure field model around a submerged cylinder and the probable location of bioluminescence was predicted.