Ask an Explorer

Questions answered during the expedition are below.

Question from:  Emma
Can a sea creature that uses bioluminescence change the color it makes?

Answer from: Dr. Edie Widder
There are a number of animals that produce different colors. There are fish that have both red and blue head lights. We think they use the blue lights like high beams for seeing at a distance and the red beams they use like a sniper scope to see without being seen.  Most deep-sea animals can’t see red light, but these fish can, so they can use their red headlights to see other animals that can’t see them coming. That’s the same principle that the Medusa works on. There are other animals that produce different colors but we have no idea why. For example, the sea pen Umbellula that looks like a beautiful lily produces green light from its stem and blue light from its flower; at least some species do. So far, the ones we have found out here seem to only produce one color.

Answer from Dr. Tammy Frank
While many species have different colors of bioluminescence in different parts of their bodies, such as the ones that Edie mentioned, the only species that we know of that can actually change the color of their bioluminescence is a species of squid that can shift from blue to green to better counterilluminate against the downwelling light field with depth or time of day. 



Question from: Emma
What behaviors have you observed of different sea life interacting with bioluminescence?

Answer from: Dr. Edie Widder
The optical lure that we use, which we call the electronic jellyfish, imitates the bioluminescent burglar alarm display of the common deep-sea jelly, Atolla. If the jelly is caught by a predator, it produces a pinwheel of light that acts like a burglar alarm to draw attention to its attacker. It’s the same reason birds and monkey have fear screams – only this is like a scream for help with light. It may attract the attention of a bigger predator that will eat the jellyfish’s attacker, thereby affording the jellyfish an opportunity for escape. We have found that particular display is especially attractive to squid. In fact, the e-jelly we are using out here is the same one we used to get the first video ever recorded of a giant squid in the deep sea. 

I have occasionally seen deep-sea shrimp spew out a series of glowing blobs in response to the flashing of a light. I think it’s a mating display. In shallow water, I have seen similar displays produced by small crustaceans called ostracods. The male ostracod swims up out of the reef or seagrass just after sunset and squirts out its bioluminescent chemicals along with a blob of mucous to produce a little glowing orb that hangs in the water. It then swims a little further and does it again until there is a string of dots in the water. Different species space the dots differently so a female can recognize a male of her own species by the spacing of the dots.

Answer from: Dr. Tammy Frank
I have also seen deep-sea shrimp use the same bioluminescent spew as a predator defense. When I've seen it, it's always been accompanied by a tail-flip in the opposite direction by the shrimp, so in this case, this incredibly bright material spewed in a predator' face is a predator defense. The predator is momentarily stunned while the shrimp swims away. It's much like the inky spew that a squid uses in a tide pool, only in the light-limited deep sea, a bright fluid is much more effective at startling a predator. 




















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