Bioluminescence in the Monterey Submarine Canyon: image analysis of video recordings from a midwater submersible

Video images of biohiminescence were recorded in situ during a 1985 study of the midwater environment of the Monterey Canyon, using a single-person, untethered submersible. Gelatinous organisms were responsible for the most brilliant bioluminescent displays, often exhibiting elaborate kinetics in response to mechanical stimulation. Images of bioluminescent displays recorded from identified organisms are shown and display patterns are described. All bioluminescence emission spectra from captured specimens were blue, with peak emissions between 460 and 494 nm. Image-analysis of recordings of mechanically stimulated bioluminescence revealed source densities between 43 and 175 m-3 and intensities between 2.5 and 37.3 #W sri m-3. The predominant display type at all depths studied (between 100 and 560 m) was luminous secretions. Despite high intensities of mechanically stimulated bioluminescence, no spontaneous light production was recorded in the absence of mechanical stimulation.