SCIENCE LAB SPECIALS : OCEAN FLOOR MYSTERIES

 

Deep Exposure : Sea lions with cameras unveil the mysteries of the ocean floor. Around much of the planet, an aquatic mystery leaves scientists in the dark.

'' For most of the ocean, we don't know what the bottom looks like,'' said Nathan Angelakis, a Ph.D. student at the South Australian Research and Development Institute [ Aquatic Sciences ] and the University of Adelaide.

So for a recent research effort, Mr. Angelakis and colleagues called in some helpers named Daphne, Phoebe, Iris and Pasithea, The four assistants, along with several others, carried underwater video cameras and dived to parts of the ocean floor off Australia's southern coast that scientists had never seen before.

Their footage shows meadows of leafy seaweeds and craggy rocks covered in corals, and even includes the first recording of a mother Australian sea lion teaching her pup how to hunt.

Daphne, Phoebe, Iris and Pasithea had a big advantage capturing sea lion footage : They are sea lion themselves. Findings from their camera work were published in the journal Frontiers in Marine Science.

Mr. Angelakis and colleagues hope their swims will help scientists better understand how sea lions use these different habitat spaces, and how humans can manage these ecosystems to ensure that the places visited by Australian sea lions, which are endangered, are not further degraded.

Scientists usually map parts of the seabed by using remotely operated vehicles and cameras towed by underwater vessels. But that can be challenging and expensive.

So Mr. Angelakis and his colleagues decided to try another way to map the remote, aquatic ecosystems around Kangaroo Island and Olive Island in Australia : They attached video cameras to the area's sea lions, which routinely dive 300 feet [ 90 meters ] beneath the surface while hunting.

Once the cameras had been retrieved, the researchers huddled around a laptop screen to review the footage. '' You get those moments which are really exciting,'' Mr. Angelakis said, such as '' when the sea lion captures a really big fish or a small shark or it's wrangling an octopus.''

The most thrilling scene was captured by Daphne. '' She was taking her pup out to sea, and that's the first direct evidence that we've collected of Australian sea lion mothers teaching or passing on their foraging skills to their pups,'' Mr. Angelakis said. [ Kate Golembiewski ]