Small, transparent sea creatures called larvaceans build mansions out of mucus that house, protect and feed them, but these “snot palaces” are so delicate that scientists have found them hard to study. Now, researchers have used lasers mounted on an undersea robot to understand the architecture of the larvaceans’ gossamer homes, reports Seth Borenstein for the Associated Press.
The new study, published this week in the journal Nature, focuses on the giant larvaceans, which, despite their name, are only about five inches long. They look like see-through tadpoles with flat, beaver-style tails, and they hang in the ocean depths capturing floating bits of food in their houses. These creatures construct their dwellings at a tiny scale and inflate them to reach sizes of more than three feet across, which is equivalent to five-story buildings compared to the larvacean’s size, according to a statement.
“Think of a balloon that hasn’t been blown up,” Kakani Katija, a bioengineer at Monterey Bay Aquarium Research Institute and first author of the new research, tells Hannah Seo of Popular Science of the structures before they’re inflated. The process is sort of similar to how a spider builds its web, but unlike with a spiderweb, these mucus houses are secreted all at once. Sadly, larvaceans don’t have the appendage advantages that spiders have either.
“A spider has eight legs to build and lay down material for its web,” Katija tells Popular Science, “this animal really just has a head and a tail.”
Since the giant larvacean’s snotty digs are too fragile to study at the surface, researchers with the Monterey Bay Aquarium Research Institute (MBARI) used a 12,000-pound, remotely-operated vehicle equipped with scanning lasers to get a closer look, reports Rosanna Xia of the Los Angeles Times.
When the robot encountered a giant larvacean, the team used its sheet-like laser beam to illuminate the design of the mucus house by tracking the movements of particles through its various cavities, per the statement. The slices of the giant larvacean’s pad illuminated by the laser’s broad beam also provided the researchers with cross-sections of its internal structure. By combining these cross-sections the team created a 3D image of the transparent animal’s filtration system, much like a radiologist taking a CAT scan of the human body.
The researchers found these snot palaces have two layers: an amorphous outer bubble and a more structured, fist-sized inner sanctum made of two fluted chambers that the larvacean pumps water through by beating its tail. Both layers filter potential food particles from the water column, and are connected…