Sea

Found: A Giant Decomposing Sea Creature

On Serum Island, part of Indonesia’s Maluku province, a 37-year-old man was walking down the beach at night, when he saw a strange shape in the water. It was a hulking, drifting mass, and from afar he thought it was a boat. But as he approached, he could see more clearly: whatever this was, it had once been alive.

The massive pile of decomposing flesh measures almost 50 feet long and has washed up…

Sea creatures’ sticky ‘mucus houses’ catch ocean carbon really fast

larvacean
MUCUS HOUSE The pale inner house (rounded flank in foreground) as well as a big, stickier outer envelope of a larvacean’s shelter could be important in ocean carbon cycles.

Never underestimate the value of a disposable mucus house.

Filmy, see-through envelopes of mucus, called “houses,” get discarded daily by the largest of the sea creatures that exude them. The old houses, often more than a meter across, sink toward the ocean bottom carrying with them plankton and other biological tidbits snagged in their goo.

Now, scientists have finally caught the biggest of these soft and fragile houses in action, filtering particles out of seawater for the animal to eat. The observations, courtesy of a new deepwater laser-and-camera system, could start to clarify a missing piece of biological roles in sequestering carbon in the deep ocean, researchers say May 3 in Science Advances.

The houses come from sea animals called larvaceans, not exactly a household name. Their bodies are diaphanous commas afloat in the oceans: a blob of a head attached to a long tail that swishes water through its house. From millimeter-scale dots in surface waters to relative giants in the depths, larvaceans have jellyfish-translucent bodies but a cordlike structure (called a notochord) reminiscent of very ancient ancestors of vertebrates. “They’re more closely related to us than to jellyfish,” says bioengineer Kakani Katija of the Monterey Bay Aquarium Research Institute in Moss Landing, Calif.

The giants among larvaceans, with bodies in the size range of candy bars, don’t form their larger, enveloping houses when brought into the lab. So Katija and colleagues took a standard engineering strategy of tracking particle movement to measure flow rates…