Sixty feet below the ocean’s surface, Earth can start to look like another planet: transparent animals drift through darkness, jellyfish glow overhead and chain-like colonies slide through the water.
In the open ocean, where there are few places to hide and many creatures cannot outrun predators, survival often depends on being hard to see. Some animals become nearly transparent. Others use mirror-like skin, bioluminescent flashes or fast-changing colors to confuse predators, attract mates or blend into water.
“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,” Johnsen says.
His fascination with light began before his career in marine biology. Johnsen spent years studying painting, sculpture and photography. That artistic eye still shapes his science, from research voyages to the delicate work of collecting deep-sea animals with submarines or remotely operated vehicles. Johnsen jokes that maneuvering around fragile creatures can feel “a little bit like trying to pick up a snowflake with a Honda.”
The payoff is more than beautiful photographs. Work on transparency has helped scientists think about cataracts, while studies of extremely dark deep-sea animals have informed ideas for displays that are readable in bright sunlight.
Johnsen calls basic research “a hedge against the future,” because discoveries made in the ocean can later surface in medicine, technology and other unexpected places. Still, he says one of the best parts of the work is watching students encounter that hidden world for the first time.
