'Eye of the Sea' Lends Fish-Eye View of Seafloor

"We are hoping to do some honest-to-goodness unobtrusive observation, which really hasn't happened in the ocean," says Edith Widder, head of Harbor Branch's Biophotonics Center and project leader. "Ultimately, the goal is to see animals or behaviors nobody has ever seen before."

The deep sea makes up about 78 percent of the planet's inhabitable volume, but little is known about most of its inhabitants, more than half of which are capable of making their own light, or bioluminescence. This scientific deficiency stems from not only a lack of exploration and study of the oceans, but also from less-than-ideal traditional research methods. Deep-towed nets can shred animals like jellyfish or damage captured animals to the point that their natural behaviors cannot be observed in the lab. Manned submersibles and remotely operated vehicles (ROVs) can deliver humans to the depths in person or virtually to observe some animals in their natural environment. However, they typically do not allow researchers to see animals' natural behaviors because the lights, motors and electric fields such vehicles bring with them are more than enough to either scare animals away before they're ever seen or frighten them into unnatural behavior.

To get around such problems, Widder dreamed of and then, in partnership with the institution's engineering division, created an innovative camera system to record life in the abyss unobtrusively. Called Eye in the Sea, the system is designed to operate on the seafloor automatically and, most importantly, unnoticed by animals. The system can detect animals nearby when they give off bioluminescent light, trigger a video camera to record the light being produced, then turn on a red light out of the animals' normal vision range to take illuminated footage. It can also be programmed to film surrounding areas at scheduled intervals, for instance when the team places the system on the bottom along with bait to attract animals. In the past camera systems used on the seafloor have relied on bright and, for those creatures accustomed to the darkness of the depths, frightening lights.

The Eye in the Sea has been tested alone during brief deployments, and has already captured unusual interactions, such as a primitive hagfish annoying a shark. Widder now plans to take the deep-sea observation work a step further by deploying the camera system along with a simple electronic device designed to mimic the various bioluminescent light patterns given off by jellyfish known as Atolla. Various Atolla species are common in the deep sea and look something like a tie-dye splotch when their round bodies are viewed from above. The artificial jellyfish lure is a round disc about six inches across with a ring of blue LED lights around its outer edge that can be programmed to light up in patterns similar to those created by the jellyfish.

Widder hopes the lure will allow her to test various hypotheses about how and why animals such as jellyfish use their bioluminescent light. For instance, when threatened, the jellyfish sometimes respond by creating a circular wave of light around their outer edge that progresses like the lights on a movie marquis. Scientists call this a "burglar alarm" response and theorize that jellyfish use it to attract large animals in to eat whatever animal is attacking the jellyfish. To test that theory and others, the team will deploy the Eye in the Sea next to a box of bait along with the artificial jellyfish, which will be programmed to produce various displays, to see how animals in the area respond. The jellyfish lure could also attract large predators to the area, which would be captured on film.

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