The weird, wonderful world of bioluminescence - Edith Widder

So I want to take you on a trip to an alien world, and it's not a trip that requires light-years of travel, but it's to a place where it's defined by light.

So, it's a little appreciated fact that most of the animals in our ocean make light. I've spent most of my career studying this phenomenon called bioluminescence. I study it because I think understanding it is critical to understanding life in the ocean where most bioluminescence occurs. I also use it as a tool for visualizing and tracking pollution.

But mostly, I'm entranced by it. Since my first dive in a deep diving submersible, when I went down and turned out the lights and saw the fireworks displays, I've been a bioluminescence junky. But I would come back from those dives and try to share the experience with words, and they were totally inadequate to the task. I needed some way to share the experience directly, and the first time I figured out that way was in this little single-person submersible called Deep Rover.

This next video clip you're going to see, how we stimulated the bioluminescence. The first thing you're going to see is a transect screen that is about a meter across in front of the sub. A mesh screen will come into contact with the soft-bodied creatures of the deep sea. With the sub's light switched off, it is possible to see their bioluminescence—the light produced when they collide with the mesh. This is the first time that has ever been recorded.

So I recorded that with an intensified video camera that has about the sensitivity of the fully dark-adapted human eye, which means that really is what you would see if you took a dive in a submersible. But just to try to prove that fact to you, I brought along some bioluminescent plankton in what is undoubtedly a foolhardy attempt at a live demonstration.

So if we get up the lights down and have it as dark in here as possible, I have a flask that has bioluminescent plankton in it. You'll note there's no light coming from them right now, either because they're dead or because I need to stir them up in some way for you to be able to see what bioluminescence really looks like.

Oh, I spend most of my time working in the dark. I'm used to that! Okay, so that light was made by a bioluminescent dinoflagellate, a single-celled alga. So why would a single-celled alga need to be able to produce light? Well, it uses it to defend itself from its predators. The flash is like a scream for help. It's what's known as a bioluminescent burglar alarm.

And just like the alarm on your car or your house, it's meant to cast unwanted attention onto the intruder, thereby either leading to his capture or scaring him away. It's a lot of animals that use this trick. For example, this black dragon fish has got a light organ under its eye; it's got a chin barbel; it's got a lot of other light organs you can't see, but you'll see them here in a minute.

So we'd have to chase this in the submersible for quite some time because the top speed of this fish is one knot, which was the top speed of the submersible. But it was worth it because we caught it in a symmetric capture device, brought it up into the lab on the ship, and then everything on this fish lights up. It's unbelievable! The light organs under the eyes are flashing; that chin barbel is flashing; it's got light organs on its belly that are flashing. Fin lights—it's a scream for help; it's meant to attract attention. It's phenomenal.

And you normally don't get to see this because we've exhausted the luminescence when we bring them up in nets. There are other ways you can defend yourself with light. For example, this shrimp releases its bioluminescent chemicals into the water, just the way a squid or an octopus would release an ink cloud. This blinds or distracts the predator. This little squid is called the fire shooter because of its ability to do this.

Now, it may look like a tasty morsel or a pig's head with wings, but if it's attacked, it puts out a barrage of light—in fact, a barrage of photon torpedoes! I just barely got the lights out in time for you to be able to see those gobs of light hitting the transect screen and then just glowing—it’s phenomenal.

So there's a lot of animals in the open ocean, most of them that make light, and we have a pretty good idea for most of them why they use it—for finding food, for attracting mates, for defending against predators. But when you get down at the bottom of the ocean, that's where things get really strange. Some of these animals are probably inspiration for the things you saw in Avatar, but you don't have to travel to Pandora to see them.

There are things like this: this is a golden coral bush. It grows very slowly; in fact, it's thought that some of these are as much as 3,000 years old, which is one reason that bottom trawling should not be allowed. The other reason is this amazing bush glows. So if you brush up against it, any place you brushed against it, you get this twinkling blue-green light. It's just breathtaking!

And you see things like this. This looks like something out of a Dr. Seuss book—just all manner of creatures all over this thing, and these are flat-wrapping enemies. Now, if you poke it, it pulls in its tentacles, but if you keep poking it, it starts to produce light, and it actually ends up looking like a galaxy. It produces these strings of light, presumably as some form of defense.

There are starfish that can make light, and there are brittle stars that produce bands of light that dance along their arms. This looks like a plant, but it's actually an animal. It anchors itself in the sand by blowing up a balloon on the end of its stalk so it can actually hold itself in very strong currents, as you see here.

But if we collect it very gently and bring it up into the lab, just squeeze it at the base of the stalk; it produces this light that propagates from the stem to the plume, changing in color as it goes from green to blue colorization. And sound effects added for your viewing pleasure, but we have no idea why it does that.

Here's another one. This is also a sea pen; it's got a brittle star hitching a ride; it's a green saber of light. And like the one you just saw, it can produce these as bands of light. So if I squeeze the base, the bands go from base to tip; if I squeeze the tip, they go from tip to base.

So what do you think happens if you squeeze it in the middle? I'd be very interested in your theories about what that's about. So there's a language of light in the deep ocean, and we're just beginning to understand it. One way we're going about that is we're imitating a lot of these displays.

This is an optical lure that I've used; we call it the electronic jellyfish. It's just sixteen blue LEDs that we can program to do different types of displays, and we view it with a camera system I developed called 'Eye in the Sea' that uses far red light that's invisible to most animals, so it's unobtrusive.

So I just want to show you some of the responses that we've elicited from animals in the deep sea. The camera is black and white; it's not high resolution. And what you're seeing here is a bait box with a bunch of, like, the cockroaches of the ocean—they're isopods—all over it. And right in the front is the electronic jellyfish.

And when it starts flashing, it's just going to be one of the LEDs that's flashing very fast. But as soon as it starts to flash—and it’s going to look big because it blooms on the camera—I want you to look right here, and it's something small there that responds. We're talking to something; it looks like a little string of pearls, basically. In fact, three strings of pearls.

This was very consistent; this is in the Bahamas at about 2,000 feet. We basically have a chat room going on here because once it gets started, everybody's talking. And I think this is actually a shrimp that's releasing its bioluminescent chemicals into the water. But the cool thing is we're talking to it; we don't know what we're saying. Personally, I think it's something sexy.

And then finally, I want to show you some responses that we recorded with the world's first deep-sea webcam, which we had installed in Monterey Canyon last year. We've only just begun to analyze all of this data. This is going to be a glowing source first, which is like bioluminescent bacteria, and it is an optical cue that there's carrion on the bottom of the ocean.

So this scavenger comes in, which is a giant sixgill shark, and I can't claim for sure that the optical source brought it in because there's bait right there. But if it had been following the odor plume, it would have come in from the other direction. And it does actually seem to be trying to eat the electronic jellyfish—that's a 12-foot long giant sixgill shark!

Okay, so this next one is from the webcam, and it's going to be this pinwheel display, and this is a burglar alarm. And that was a Humboldt squid, a juvenile Humboldt squid about three feet long. This is at 3,000 feet in Monterey Canyon. But if it's a burglar alarm, you wouldn't expect it to attack the jellyfish directly; it's supposed to be attacking what's attacking the jellyfish.

But we did see a bunch of responses like this. This guy's a little more contemplative—hey, wait a minute, there's supposed to be something else there! He's thinking about it, but he's persistent. He keeps coming back, and then he goes away for a few seconds to think about it some more and thinks maybe if I come in from a different angle—nope!

So we are starting to get a handle on this, but only just the beginnings. We need more eyes on the process, so if any of you ever get a chance to take a dive in a submersible, by all means, climb in and take the plunge. This is something that should be on everybody's bucket list because we live on an ocean planet. More than 90%, 99% of the living space on our planet is ocean.

It's a magical place filled with breathtaking light shows and bizarre and wondrous creatures—alien life-forms that you don't have to travel to another planet to see. But if you do take the plunge, please remember to turn out the lights. But I warn you, it's addictive. Thank you!