Widder and Case then built what they called a high-intake defined-excitation bathy-photometer—or Hidex-BP, for short. They mounted it on a framework and towed it through the water. It pumps 20 liters (about 5.3 gallons) of seawater and plankton per second through a “light tight” collection chamber large enough to capture even fast swimmers and keep them inside long enough for the device’s fiber-optic instruments to record and measure, in photons per liter, the size, duration, and number of an organism’s flashes.
From her graduate study of dinoflagellates, Widder knew that an animal’s first flash is the brightest and that to obtain clear readings, the creature must be stimulated and contained long enough to measure all the light given off. No one had managed to do this systematically before, and the device was successful. The Navy’s entire bioluminescence database rests on the device and a second-generation version.
Widder is working on a third-generation unit that will offer better mapping of the distribution patterns of light. Over the years, better instruments have been the key to Widder’s research. “I’ve combined all my interests by engineering toys for ocean exploration,” she says.
 |  |  |
Courtesy of Edith Widder/Harbor Branch Oceanographic Institution
Sometimes a scientist is lucky enough to recover a rare and remarkable animal. That happened to Widder in 1997 when she took a Johnson-Sea-Link submersible down to 2,477 feet in the Oceanographer’s Canyon off Georges Bank in the Gulf of Maine. There she saw an octopus, which started glowing back in the lab. At the time only two of 43 genera of the creatures were known to display bioluminescence. Here was another. “It was evolution caught in the act,” she says. “The octopus’s suckers were turning into light organs.” She thinks the creature once lived on the bottom in shallow water and then moved into deeper, darker environs, where it evolved the light-up suckers to attract food. “The suckers actually twinkle, and they look like the dinoflagellates on which copepods feed,” Widder says. “The copepods approach, and when the octopus slowly closes into what we call a turban posture, the copepods get stuck in mucus surrounding the octopus’s mouth. The octopus gut shows that copepods are what they eat.”
Revelation at the bottom of the sea is normal. “Every time I go down there I see something I’ve never seen before,” Widder says. “And every four or five times, I see species nobody’s seen before.”
Quantifying bioluminescence was a leap that allowed Widder to accurately describe the midocean environment as a minefield. She could then move on to bioluminescence as a tool for locating and mapping various populations of animals and observing how they overlap.
Scientists once thought of the ocean as a vast, undifferentiated soup, but Widder’s work shows that it has a high level of organization and stratification. For instance, copepods, which are tiny crustaceans, tend to gather and feed at certain levels of salinity and temperature. That knowledge, of course, raises further questions. Are other fish more likely to be there, too, feeding on copepods? Do other creatures avoid high levels of bioluminescence, which might attract predators?
Widder soon realized that she could identify many animals by the type and duration of flash they made—jellyfish, for example, might appear as a bright circle in the darkness. That meant bioluminescence could tell her which animals were where, which others they associated with, how they interacted, and how such variables as light, salinity, temperature, and pollution affect their habits and distribution. She could study behaviors and relationships, adding significantly to science’s understanding of undersea life.
The field is young and full of surprises. At the Monterey Bay Aquarium Research Institute, for example, marine biologist Steven Haddock recently discovered that certain jellyfish cannot manufacture their own luciferin and that they probably get it from eating small crustaceans. Yet jellyfish are among the oldest creatures on Earth, and one might have presumed their bioluminescence evolved early on.
But bioluminescence research is held back by the difficulty, danger, and expense of getting where the action is. “If we put the same funding into the ocean as NASA does into space, the results would be tenfold,” Widder says. “Drugs from the sea is just one example—you’ll never get that from space.”
If Widder had NASA’s budget, she would build undersea observatories to unobtrusively sit and watch creatures in search of an answer to a central question: What’s the background level of bioluminescence when humans are not there to stimulate its production? Without that budget, she hopes her new invention, called Eye in the Sea, will help. The device is an infrared and visible-light camera that will sit on a tripod on the seafloor, emitting light on a wavelength believed to be invisible to most sea animals. It’s a tricky design problem: The Eye has to be stable, leakproof, and capable of amplifying light on a suitable wavelength the way night-vision goggles do.
Widder has worked on it for a decade with no grant money and little help. Two years ago, she built a prototype and used a remote undersea vehicle to install it 6,400 feet deep in Monterey Canyon off the California coast. When she hauled it up, the case was flooded. “Success in life depends on how well you handle Plan B,” she says. “Anybody can handle Plan A.”
Plan B was to fix the leak and try again. This time she got pictures. At first, she was pleased. The fish didn’t startle when the light came on, and she assumed they hadn’t spotted it. But when she studied the film more carefully, she saw that when the light came on, the fish began to move away. So this year it’s on to Plan C. She has no intention of failing to capture “the best light show on the planet” faithfully and unobtrusively. “We know so little about these animals,” she says. “I’m very interested to see what these bizarre displays are about, these totally bizarre behaviors we just don’t understand yet.”
