Near Fernando Noronha the sea gave out light in flashes. The appearance was very similar to that which might be expected from a large fish moving rapidly through a luminous fluid. To this cause the sailors attributed it; at the time, however, I entertained some doubts, on account of the frequency and rapidity of the flashes. With respect to any general observations, I have already stated that the display is very much more common in warm than in cold countries. I have sometimes imagined that a disturbed electrical condition of the atmosphere was most favourable to its production. Certainly I think the sea is most luminous after a few days of more calm weather than ordinary, during which time it has swarmed with various animals. Observing that the water charged with gelatinous particles is in an impure state, and that the luminous appearance in all common cases is produced by the agitation of the fluid in contact with the atmosphere, I have always been inclined to consider that the phosphorescence was the result of the decomposition of the organic particles, by which process (one is tempted to call it a kind of respiration) the ocean becomes purified.
– Charles Darwin
The passage reminded me of this exchange between Steve Zissou and Ned Plimpton:
Ned Plimpton: Steve what produces this effect of illumination? Is there a chemical inside the organism?
Steve Zissou: No Ned actually the reflection of the moonlight on their outer membrane…that’s a very good ad lib.
This post was inspired by this essay: Charles Darwin: The Best Scientist-Writer of All Time
Darwin, Charles. Voyage of the Beagle. United Kingdom, Penguin Publishing Group, 1989. pp 152,153



