Finding Beauty in the Invisible: Sönke Johnsen and the Language of Light

Imagine floating 60 feet below the ocean's surface, tethered to a lifeline so you don't drift away. Large jellyfish drift overhead. Around you, 20-foot-long transparent, chain-like structures snake silently through the darkness, each composed of hundreds of individual animals. Strange creatures shimmer, vanish or glow with light of their own. 

"You really feel like you've left the Earth and you've moved to a water planet where the animals aren't like anything you could ever imagine," says Sönke Johnsen, Ida Stephens Owens Distinguished Professor of Biology and of Marine Science and Conservation. "Between the sun coming down and the animals glowing in their transparency, it's just remarkably beautiful." 

For almost three decades, Johnsen has been trying to understand how these animals use light as a tool for survival. 

Out in the open ocean, survival is a challenge unlike almost anywhere else on Earth. There are no trees to hide behind, no rocks to squeeze beneath, no burrows to disappear into. Many animals are simply too slow to outrun a predator. Instead, a different solution evolved: become part of the water itself. 

"Many of the animals that can't run away do their best to become transparent, so they look like the water around them," Johnsen says. 

Transparency is only one trick in these animals’ remarkable optical toolbox. Some cloak themselves in mirror-like skin that reflects the surrounding water. Others generate flashes of light through bioluminescence. Squid, octopuses and cuttlefish can rapidly rearrange pigments and reflective cells beneath their skin, changing color and pattern in an instant. 

"If they really wanted to put their minds to it," Johnsen says with a laugh, "they could play a movie on their bodies." 

Compared to them, humans aren't particularly impressive. 

"We're actually visually very boring animals," he says. "We only have a few little colors on our bodies, and we can't really change them, except maybe to blush or something like that, or to get a tan." 

These extraordinary abilities all depend on microscopic structures on the animals’ skin or shells that allow them to bend, scatter and reflect light with astonishing precision. The effect is similar to the rainbow colors in a soap bubble or the tiny grooves on a CD that catch the light from different angles. 

For Johnsen, the appeal isn't just that these animals are scientifically fascinating. It's that they're beautiful. 

Long before he became a marine biologist, Johnsen studied painting, sculpture and photography. His fascination with light began in the art studio, then followed him into physics, mathematics and eventually the ocean. 

"I've just always been drawn to light and how things manipulate light," he says. 

That curiosity has taken him around the world aboard research vessels that spend weeks at sea. This August, he'll once again board a ship nearly 300 feet long, heading offshore for another month collecting some of the ocean's most unusual inhabitants. 

Finding them is only the beginning. 

Many live a mile or more beneath the surface, requiring submarines or remotely operated vehicles equipped with clear collection chambers. Piloting one around a small, delicate and often soft-bodied creature without damaging it is no easy feat. 

"It's a little bit like trying to pick up a snowflake with a Honda," Johnsen says. 

Even after the animals are safely onboard, photographing them can become an exercise in patience. 

“There are three of us handling the camera, the lights and making sure the animal is in the right place. We're usually taking at least 100 photos to get one good one,” he says. 

The images are worth the effort. Transparent tissues, mirror-like bodies and flashes of blue-green light reveal a world that seems almost imaginary — until you remember that almost all these creatures are solving the same basic problem: how to avoid becoming someone’s dinner. 

The lessons don't always stay underwater. 

Research driven by curiosity has a habit of resurfacing in unexpected places. Johnsen points to his group's work on transparency, which later helped researchers better understand why the lenses in our own eyes become cloudy with age, leading to cataracts. The same principles that make some deep-sea animals extraordinarily dark have also inspired engineers designing displays that remain visible in bright sunlight. 

"I think of research funding, especially for basic research like this, as sort of a hedge against the future," he says. "We're studying how an animal does something deep in the ocean relative to other animals. Then later on, we discover that this is incredibly useful for some sort of technology." 

Still, technology isn't why Johnsen studies that. 

After 29 years studying the ocean, he says the greatest reward is watching students experience it for the first time. Every expedition brings a new group of young scientists who see transparent animals, glowing comb jellies and the vast open ocean with fresh eyes — and ask questions no one else has thought to ask. 

"You get to see them excited about these things that have excited you for a long time," he says.  

"I once described it as running down the up escalator. You get to keep watching this wonderful thing happen, which is younger people learning about how beautiful things in the ocean can be."

To learn more about the wondrous creatures inhabiting the open ocean — and the scientists who study them — check out Johnsen’s latest book, “Into the Great Wide Ocean: Life in the Least Known Habitat on Earth.”