Acanthascus is a glass sponge in the class Hexactinellida. We found this sponge at around 95 m depth when we were exploring a sponge reef at the north end of Vancouver Island, British Columbia.
We asked the pilots of ROPOS - the remotely operated vehicle - to release a tiny bit of fluorescein dye near the side of the sponge. (The pipette bulb end on our dye system stops it pouring out, so we can squirt controlled amounts which the sponge sucks through its body wall using flagella pumps.)
At 11 seconds into the movie you can see a stream of green coming out of the chimney (osculum) as the sponge pumps the water through the body wall to extract tiny bacteria in the water for food.
