Ep. 42 – Edie Widder on the ocean’s spectacular light

Early in her career, the ocean explorer and scientist Dr. Edie Widder received a phone call from a distraught physicist. The physicist was working on a major project aimed at detecting neutrinos, elusive subatomic particles that can give off faint flashes as they move through water. He and his colleagues needed the darkest place they could get, so they placed their ultra-sensitive light detectors deep in the ocean, beyond the reach of the sun’s rays. But there was a problem. The sensors were detecting a lot of light. A colleague suggested the light could be from animals. ‘Could it be true?’ the physicist asked Dr. Widder, now a world authority on marine bioluminescence. ‘Yes,’ she told him. And then, after a long pause, he followed up: ‘Is there some place in the ocean where there isn’t any bioluminescence?’ ‘Not that I know of,’ Dr. Widder replied.

Edie Widder
“The open ocean is a place without hiding places,” Dr. Edie Widder tells us, explaining the origin of bioluminescence in the ocean’s creatures. “As the ocean filled up with predators that could see at a distance and swim fast, the only hope for prey was either to out-swim their predators or find a way to hide. And the best way to hide was to go down into the darkness. The problem is, the food is produced at the surface through photosynthesis.  So animals would hide in the dark depths during the day, and only come up and feed in the surface waters under the cover of darkness. As a consequence, most of those animals spend most of their lives in darkness or near-darkness. So there’s been a lot of selective pressure to develop more sensitive eyes and advanced visual signaling, which is where bioluminescence comes in.” (Photo courtesy of Penguin Random House.)

Like many of us land-lubbers, the physicist had assumed that light-making among ocean creatures is an exotic and rare phenomenon. But that’s wrong. The majority of animals in the ocean — which means the majority of animals on the planet — are capable of making light. From top to bottom, the ocean is absolutely teeming with unforgettably beautiful and extraordinarily diverse light shows made by living things that we’re only beginning to understand. There are deep-sea shrimp that spew glowing mucus like fire-breathing dragons to distract predators. Single-celled algae that glitter en masse as a form of burglar alarm. Crustaceans that put on complex, twinkling courtship displays. Fish that counter-illuminate their bodies to match the water above them for camouflage from creatures looking up from below. Squids that backlight their body tissue in flickering patterns that seem to coordinate group hunting. These are just a few examples of the roughly 75 percent of ocean animals that can make their own light. According to Dr. Widder, there are possibly quadrillions of light-producing fish in our seas.

Deep-sea shrimp, Heterocarpus ensifer, releasing bioluminescent “spew.” (Photos by Sönke Johnsen and Katie Thomas, licensed under CC-BY-SA-2.0.)
The deep-sea jellyfish, Atolla wyvillei, produces a “burglar alarm” display when attacked by a predator — a magnificent lightship meant to attract an even larger predator to attack its attacker, giving it the opportunity to escape. (Photo by Edie Widder, licensed under CC BY-SA 2.0.)
Eye-in-the-Sea, an autonomous, battery-powered camera and illumination system that uses red light and a highly sensitive camera to record bioluminescent animals unobtrusively. The equipment, designed by Dr. Widder, has been used to record many behaviors by marine animals never before seen. 
(Photo by NOAA/OER, licensed under CC BY 2.0).

Dr. Widder has devoted her career to exploring this phenomenon of marine bioluminescence, which she contends is one of the most important, widely used, and vastly under-appreciated forms of communication in nature. It’s also one of the most magical, as her marvelous new book, Below the Edge of Darkness: A Memoir of Exploring Light and Life in the Deep Sea, will convince you. For decades, Dr. Widder has trail-blazed both intellectual and physical frontiers as a deep sea explorer, oceanographer, inventor, and marine biologist. She has been a leader in designing, inventing, and piloting new submersibles and equipment to enable humans to observe animals in the deep sea unobtrusively. Her innovations have produced many observations of animals and bioluminescence never before seen, including the first footage of the giant squid in the wild. Dr. Widder is the co-founder, CEO and senior scientist of the Ocean Research & Conservation Association, a non-profit that develops innovative technologies to protect ocean health.

In this episode, we speak with Dr. Widder about ocean animals’ language of light, her extraordinary career exploring mysteries of in the deep, how dim our understanding of much of the ocean still is, and why she believes investing in ocean exploration is key to ocean protection.

In Below the Edge of Darkness, Widder tells the story of the brilliant bioluminescence she witnessed during her first journey into the deep ocean. “It’s like a fourth of July fireworks display, only you’re not observing it from afar,” she says in our interview. “You’re in the center of it. In fact, you’re causing it. And it’s this amazing spewing of light all around you, which flashes and glows and sparkles … I was just mesmerized by this incredible world that clearly we know nothing about, and now I realize constitutes most of the life on our planet, and it’s just filled with light.” (Image courtesy of Penguin Random House.)

Edie Widder’s recommendations:

Alien by Ridley Scott

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