Bioluminescence of Marine Dinoflagellates : I. An underwater photometer for day and night measurements.

Portable light-baffled underwater photometers have been designed for the measurement of dinoflagellate bioluminescence by day and night. Maximal light emission is obtained by mechanical stimulation in a defined volume. The pump which stimulates the dinoflagellates also constantly replenishes the sample volume so that continuous measurements are possible. Evidence for both diurnal variation and vertical migration is presented. Using luminous bacteria for calibration a single dinoflagellate has been found to emit of the order of 10(10) light quanta per flash. The technique suggests that large scale mapping of bioluminescence is feasible.