When everyone was busy watching the sea cucumbers and urchins on the old time-lapse photos of the seafloor from cameras 2.5 miles below the ocean’s surface, a woman named Amanda Khan was, apparently, watching something else on the time-lapse photos — she was watching the sponge. And then, throughout the course of the video, the sponge suddenly changed size.
Kahn and her co-author Clark Pennelly, an atmospheric researcher at the University of Alberta, took a closer look at the images and found that several glass sponges, which stick up from the seafloor like tulips, seemed to contract and expand in a rhythmic pattern over time. The researchers saw similar movements from sputnik sponges, which periodically unfurled and retracted their "parasol-like" filaments in the surrounding water. "It's not yet known what the timing of those rhythms are or why they happen the way they do," Kahn added.
Apparently, the process is similar to why we sneeze.
More details about this over at Live Science.
(Video Credit: Monterey Bay Aquarium Research Institute (MBARI)/ YouTube)