Absurdly cute and incredibly informative footage, courtesy of 8 female sea lions. Photo: YouTube//Screenshot
There’s a lot we don’t know about the ocean, but researchers in Australia enlisted sea lions to help us learn more about it.
According to the National Oceanic and Atmospheric Administration (NOAA), we’re not even close to knowing what the majority of things look like under the surface.
“Given that the ocean is the largest living space on our planet and covers nearly 70 percent of Earth’s surface, it seems that perhaps we ought to know a bit more about the planet we call home. But we don’t,” NOAA wrote. “We have only explored five percent of our world ocean. That means that 95 percent of our ocean is unknown.”
Just 26 percent of the sea bed itself has been mapped, so there’s plenty on the sea floor that we’re literally in the dark about, too.
Enlisting the help of sea lions was an idea from Nathan Angelakis, who researches ecology and evolutionary biology at the South Australian Research and Development Institute in West Beach. Using lightweight cameras, the sea lions simply swam around their usual routes off the southern coast of Australia. Then, after compiling all the footage, Angelakis and the rest of his team used a machine learning model to combine the videos. Their findings were published on August 7 in Frontiers in Marine Science.
“These are particularly deep and remote offshore habitats that you can’t get to by usual surveys that you would conduct from a boat,” Angelakis said to Nature. “With the data we’re collecting, we’re essentially exploring new parts of the ocean that haven’t been mapped.”
While the sea floor might not seem all that interesting to some — it is, for the most part, pretty sparse — understanding it as well as we can is important. It helps with marine conservation, navigation and predicting hazards such as tsunamis.
“You can’t manage what you haven’t measured,” said Steve Hall, head of partnerships at the ocean-mapping organization Seabed2030, which is based in Liverpool, UK, to Nature.
There are a variety of reasons why we’ve only mapped a quarter of the sea floor. The deep sea is rife with challenges, like crushing pressure and inky blackness. Usually, researchers have done most of their mapping using ROVs or simply by dropping a camera on a line down from a boat, but since sea lions are already cruising around down there, it is cheaper and easier to have them act as camera operators.
The team used wild Australian sea lions, which spend most of their lives searching for food on the sea bed along the continental shelf. The researchers hoped that they’d be able to get a relatively accurate map of the sea floor by tracking their movements as the sea lions swam over it.
Using neoprene and glue, they stuck sensors on the back of the sea lions. GPOS trackers, cameras, and motions sensors were all included, but tiny little ones that weigh almost nothing. When the project was finished, the whole works were removed from the sea lions without harming them. In all, the animals were able to collect nearly 90 hours of footage that “showed six distinct sea-floor habitats, from bare sand to meadows of algae.”
Still, though, even after compiling all the footage, it wasn’t exactly clear just how accurate the models would be, so they cross-checked it all with a machine-learning model created to predict sea floor habitats by using sea-surface temperature and distance from the coast. When they compared the machine-learned information with the real footage, they found a surprisingly high level of accuracy — around 98 percent. With that confidence, they were able to map other sea floor locations in nearby locations.
“One of the real powers of the study is taking the data we collected to predict other unknown areas,” Angelakis told Nature.
Next, the team plans to use the data they collected to figure out how things like the nutrients in the water column and the depth might affect “the ecological value of different habitats and marine areas to sea lions.
“This study highlights the value of ancillary data collected from animal-borne video,” the researchers concluded, “beyond solely investigating animal behavior, and illustrates how future research could repurpose such data in novel ways, to address important research objectives in the marine environment.”
