The elusive harp sponge dwells nearly two miles below the surface of the ocean, far deeper than humans are able to explore. No one even knew they existed before scientists off California’s Monterey Bay used a remote control vehicle to spy on the meat-eating sponge from afar. Their findings, published Oct. 18 in Invertebrate Biology, reveal the secrets of this slow-motion hunter.
The harp sponge, Chondrocladia lyra, has thin vertical fingers covered in fibers similar to Velcro. These barbs snare small crustaceans swept up in deep ocean currents. The sponge then wraps these tasty morsels in a thin membrane, dismembers them into bite-size pieces, and voila! Let the slow digestion process begin!
The sponge’s sticky fibers also come in handy for reproduction. Spheres at the end of the harp sponge’s branches produce compact balls of sperm, called spermatophores, which they release into the water. Neighboring sponges snag these sperm-bearing packages in order to fertilize the eggs contained farther down their branches.
Cameras on the researchers’ remote control vehicles also revealed that the harp sponge has many neighbors in its deep sea home, including sea anemones, sea pens, and sea cucumbers.
Image courtesy of Monterey Bay Aquarium Research Institute (MBARI)