Luminous Life - Light-Up Slime

As I've been researching bioluminescence, the ability of some organisms to produce light with virtually no heat (there's a powerful metaphor right there), I learned that there are different types of bioluminescence: intrinstic or internal, where the organism has specialized cell structures to produce its own light; bacterial, where the organism needs to partner with bacteria to generate light; and extracellular, where the organism creates luminous slime.

Yes, glowing slime. It sounds like the next big thing in toys. But a surprising number of creatures secrete bioluminescent slime, and it's not always clear why.

The image above shows bamboo coral that, if touched, will produce "astonishing" amounts of slime, but scientists don't understand its purpose. Another sea creature, the Venus fly trap anemone, was also found to be bioluminescent not that long ago, again by way of slime and again for unknown reasons.

Certain centipedes, squids, shrimp, earthworms and tube worms can produce luminous secretions. Possible uses include defense against predators, communication and mating, which is the case with the Bermuda glow worm. In the summer months, these sea-dwellers swim to the surface to mate, with the females exuding a glowing slime to attract the males. The males respond with their own flashes of blue light, seen below.

That makes sense, and it's also interesting that their mating ritual occurs 2 to 3 days after the full moon and exactly 56 minutes after sunset. There are boat tours to view the phenomenon, it's that regular.

Still, that leaves a lot of radiant slime whose purpose remains clouded. Why would worms, like the ones above, ooze light? There is no satisfactory answer; I can only accept that these supposed lowly creatures have, by their unusual capacity, caused me to rethink the sources of light that exist in the world, as I consider beautiful light transported via mucus, protecting and otherwise serving its creator.