Better science through bubble-free diving

Many ocean animals are masters of stealth and disguise. The ability to run away and hide is invaluable when you live in a world full of watchful, nimble predators. Unfortunately for friendly scientists, some critters’ skittish demeanor can get in the way of research. In response, our dive team is employing its own stealth technology: the rebreather.

When divers use rebreathers, there’s no tell-tale stream of bubbles to alert ocean animals to their presence. Photo courtesy George Z. Peterson.

Rebreathers allow divers to breathe in and out in a closed-circuit loop. Breathable air comes in through one side of the dive mask, while carbon dioxide-rich exhaled air leaves through another to be scrubbed and recycled. Along with enabling longer, deeper dives, rebreathers have another huge advantage: They’re bubble-free.

When scuba divers swim into the depths of the ocean, they breathe air through a hose attached to a tank. When they exhale, a steady stream of bubbles floats to the surface. These bubbles – an unusual feature in the ocean landscape – can cause wary ocean animals to dart into their hiding spots, evading researchers who are trying to observe them.

Divers using rebreathers capture sea otters as part of field research studies. Photo courtesy California Department of Fish and Wildlife.

With rebreathers, divers can be much stealthier. They’re able to swim closer to animals without disturbing their daily routines.

“You can get up close and see some animal behaviors you may have never seen before,” said George Z. Peterson, director of dive programs at the aquarium.

Some of our divers have been using rebreathers since 2007, mostly to aid with sea otter captures that are part of our collaborative research to tag and track otters in the wild. But George is excited about the technology’s potential use with other research and husbandry projects.

It might be easier to observe skittish animals like harbor seals. Photo ©Peter Bridson.

For scientists, rebreathers may offer a more accurate glimpse into a day in the life of a rockfish or a crab. It may also allow for more accurate counts of animal populations in the wild. Our Conservation Research team thinks rebreathers may allow for easier observation of extremely mobile animals like seals.

Many observational studies of underwater animals are carried out using remotely operated vehicles (ROVs). While these machines aren’t very obtrusive to the animals, they’re still cumbersome to operate. In contrast, skilled divers are quite agile in the water.

By using rebreathers, divers hope to observe behavior of rockfishes and other animals without disturbing them. Photo © Bill Morgan.

George said our Husbandry staff is excited about using rebreathers to observe animal behavior in the wild so that they can better recreate their environments in our exhibits. When exhibits are more hospitable, the animals are healthier.

Since rebreathers also allow divers to go deeper than they could using traditional scuba gear, our team may get some up-close and personal views of animals only seen by scientists using ROVs. It’s possible, though unlikely, that the stealth technology will even allow divers to observe some animals for the first time.

“It’s a really neat way to observe animals in their natural habitat,” George said. He’s looking forward to even more bubble-free diving in the near future.

– Cynthia McKelvey