Records of Bioluminescence in the Ocean 1 
Brian P. Boden and Elizabeth M. Kampa 2 * * 
During the month of June, 1955, while 
measurements were being made of the depth 
of penetration of moonlight into the sea off 
the Kona Coast (S. W. coast) of the island of 
Oahu in the Hawaiian group, some informa- 
tion was obtained on bioluminescence in deep 
water in this region and on the effect of 
moonlight on the vertical distribution of 
luminescent organisms. Observations of bio- 
luminescence were also made off San Diego, 
California, during the month of January, 1956. 
An underwater photometer (Kampa, 1955; 
Snodgrass et al ., 1957 in press) designed for 
work in the deep sonic-scattering layers was 
used for these measurements. This was 
equipped with a depth-indicator (Boden et al ., 
1955) so that a precise knowledge of the 
depth of the instrument was available at all 
times. The instrument utilizes a 931-A photo- 
multiplier tube oriented with the sensitive 
surface facing up. In front of this is a col- 
limating tube at the base of which is a filter- 
holder for interference filters. The collimator 
ensures that the 5° useful angle of the filters 
1 Contribution from the Scripps Institution of 
Oceanography, New Series, No. 910, and from the 
Marine Laboratory, University of Hawaii, No. 90. This 
paper represents the results of research carried out by 
the University of California in part under contract with 
the Office of Naval Research. Reproduction in whole 
or in part is permitted for any purpose of the United 
States Government. 
2 Scripps Institution of Oceanography, University 
of California, La Jolla, California. Manuscript received 
February 27, 1956. 
is not exceeded. At the distal end of this tube 
is a diffusing plastic disc, which is a true 
Lambert-type collector— that is, under a uni- 
form sky the intensity (I d ) collected from the 
direction 0 would be 
Iq = I 0 cos 0. 
Thus the instrument measures irradiance. The 
collimating tube and filter-holder are free- 
flooding. The dark-current level of the instru- 
ment changes less than 0.2 millivolts on the 
0-10 millivolt recorder range through the 
temperature range 10-30°C. It fluctuates 
about 0.03 millivolts at any particular tem- 
perature. The instrument registers down to 
1 X 10~ 6 ju watts/cm 2 . 
Observations of bioluminescence in surface 
waters were made off San Diego (Lat. 32° 38' 
N., Long. 117° 35' W.) on the morning of 
January 18, 1956. 
The photometer was lowered with its sensi- 
tive surface pointed downward. The sky was 
cloudless and moonless, and the first cast was 
made immediately before the beginning of 
official twilight. Luminescence was clearly 
visible at the surface at this time, and por- 
poises were seen to leave bright trails of light 
in their wakes. 
Flashes, or bursts of light, were observed 
by the instrument, and recorded on a Leeds 
and Northrup Speed omax recorder, from the 
surface to a depth of 60 meters. From a depth 
of about 25 meters downward the flashes were 
superimposed on the dark-current level of 
229 
