During one of MBARI’s expeditions to Mexico’s Gulf of California, researchers observed what looked like small pom-poms lying on the seafloor. These mystery masses turned out to be a spectacular spaghetti worm: Biremis.
This shaggy species was previously known solely from the Bahamas. Upon further examination and DNA testing by our expert collaborators at Scripps Institution of Oceanography, we realized we had encountered a new species of Biremis.
Biremis has no eyes, no gills, and lacks obvious chaetae along its body segments. It’s also unusual because its tentacles are inflated giving it the pom-pom appearance that caught the researchers’ attention. The Gulf of California species is deep-dwelling, with the majority of our observations deeper than 2,000 meters (6,600 feet).
Spaghetti worms are a type of polychaete worm grouped in the family Terebellidae. This family of worms is found worldwide. Scientists have described about 400 different species of terebellid worms. They’re relatively common and characteristically have numerous grooved tentacles for feeding.
Like other terebellids, Biremis lives on the ocean bottom, but while most live in a tube or burrow, this species has been observed resting on the seafloor or swimming just above it. Swimming freely allows the worm to easily move around and find new places to feed. Biremis uses its bountiful bundle of non-retractile tentacles to harvest particles of marine snow that have settled on the seafloor. If you look closely at the video, you can see the trail the animal has made in the mud.
On International Polychaete Day, July 1, we celebrate the remarkable diversity of polychaete worms. Scientists have discovered and named more than 12,000 living species of polychaetes and no doubt many more await discovery in the ocean’s mysterious depths.
The ocean faces many threats, such as overfishing, pollution, and climate change. These threats extend to the waters deep beneath the surface too. Because we know so little about the deep ocean, MBARI's efforts to document the diversity of life in this realm are laying the foundation to understand how these threats will affect deep-sea communities.
