Because the majority of living space on earth is in the deep ocean, below the zone of bright light, bioluminescent light is almost certainly the most common form of communication on the planet. Flashes and glows can be used in many different ways, and sometimes there can be four different functions of bioluminescence in a single animal!

We have found that luminescence is very widespread among animals that we can see with our remotely operated submersibles (ROVs): We found that 76% of creatures in the water column, and 45% of those living on the bottom are able to make their own light. This applies from the surface all the way to 4000 meters deep.

To learn more about bioluminescence we are applying new tools both at sea and in the lab. Using a special low-light camera on the ROV, we can film bioluminescent behaviors, many for the first time.

Using genetics and chemical tools, we are studying the biochemical basis and origins of bioluminescence. We’ve found that the most common light-emitter in the sea — the luciferin coelenterazine — is missing in some jellies, which have to get it from their diet. Others can synthesize their own, possibly using a special gene, and we are hoping to figure out this biosynthesis pathway. Ctenophore biosynthesis paper (bessho uehara). These studies show that having non-luminous species to use as natural controls can make important contributions.

On our ROV dives, we have witnessed bioluminescence for the first time in many animals: the Green bomber worm Swima, the lures of the angler siphonophore Erenna sirena, bioluminescent arrow worms, doliolids, vampire squid tentacles, sea anemones the first luminous sponge.

We have also found that some animals use fluorescent lures to create brightly colored attractants in the monochromatic blue environment: Olindias, Rhizophysa  and Resomia.

Many of our findings, and summaries of the functions of bioluminescence are found in our comprehensive review paper.

Finally, we are using MBARI’s autonomous underwater vehicles (AUVs) to map the oceanographic distribution of bioluminescence and to evaluate which species are making the light based on the characteristics of the flashes measured.