Despite my love of night diving, I've logged far fewer hours than I'd like underwater between sunset and sunrise. There just doesn't seem to be enough interest at the dive resorts I'm frequenting to ensure many nighttime adventures away from the mini-discos. (I've got a toddler.)
But like many other divers, I never tire of the thrill of seeing it ("them," in actuality, since it's dinoflagellates generating all that oversized light) erupt of my arms and fins like white light off a welder's blast.
The most striking instance of bioluminescence I've been treated to was near Dahab, in the Red Sea, as a pair of 7-10cm fish bobbed and spun around me in a game of hide-and-seek -- or "She's mine! No mine!" Even as I swam reluctantly off I could see their blacklight theater from a full 15 meters away. It was a pair of so-called common flashlightfish, the Steinitz' Flashlightfish (Photoblepharon steinitzi).
But aside from the benefits that all this organic glowing yields its owners, there are some folks thinking up interesting applications for bioluminescence. One is its use as an imaging technique to monitor turbulence such as breaking waves. And make no mistake, it's a science; these folks at the Innovative Marine Technology Lab are pinning down "different species of dinoflagellates [to] offer a range of size, flow thresholds, flash brightness, and flash duration."