"0:01-0:15 — the stunning crown of a filter-feeding annelid worm. Worms like this live in tubes or burrows, with only their delicate feeding structures exposed. Once a food particle is ensnared, cellular hairs guide it to the central mouth.
0:22-0:45 — a soft coral colony. Known as “octocorals”, soft corals are different from the more familiar hard corals in that they don’t have a hard skeleton. Instead, they use a complex mesh of biomolecules to shape the colony. Soft coral polyps also have 8 tentacles, hence the name “octocoral.”
0:46-0:55 — This is a close-up of a mushroom coral (Discosoma sp). This looks like a solitary species. Solitary corals are, well, exactly that, single coral polyps that live alone, not as part of a colony. They can be quite large, I often see solitary corals about the size of a human hand.
0:56-1:01 — Favites pentagona, known by the shamelessly amusing common name of “red and green war coral”.
1:01-1:04 — This is a species of hermaphroditic cup coral, called Acanthastrea lordhowensis.
1:05-1:20 — A polyp digging its way out of sediment. Amazing! I think this is, again, a solitary coral polyp.
1:20-1:35 — no idea, but I want one.
1:36-1:40 — hmmm….
1:41-1:51 — A little coral polyp opening up at night. According to Daniel it’s the same species as above.
1:52-2:02:01 — DEAR GAWD! Is that the excurrent canal of a sponge?! I can’t think of what else it would be, but at the same time I kinda don’t believe it. Sponges (those animals that look like rocks and gave us the dish sponge) have a network of tiny pores along their surface. These pores suck in water and the animal then filters out food particles. All the water eventually leaves the sponge through a large opening, or excurrent canal. But….I had no idea they moved…
2:02-2:26 — ok, all these look like sponges, but I’m still finding it hard to believe. *Update* Yep, they’re sponges. According to Daniel, “Sponges regulate water flow by means of adjusting the diameter of their canals (in addition to speed of flagella beating). You can actually see individual cells working to make the seal.”
2:27-2:33 — beautiful little coral polyps. According to Daniel it’s a goniopora.
2:34-2:38 — stunning. More Acanthastrea lordhowensis polyps (starry cup coral).
2:38-2:44 — According to Daniel, it’s a Favia.
2:45-2:52 — A beautiful “rainbow lobophyllia.”
2:53-3:00 — A purple zoanthid colony. Zoanthids are similar to corals, widely distributed, and popular with photographers and aquarists. Surprisingly, from a scientific perspective, we know very little about them.
3:00-3:02 — hard coral polyps of some kind.
3:12 — more soft corals, known as octocorals.
3:13-3:19 — A sea urchin! The yellow structures are spines. The brown worm-like structures with white tips are tube feet. Urchins use tube feet to move around, stick to things, and even sense light! The little blue structures are called pedicellariae. Pedicellariae are like little claws the urchin uses to grab onto rocks or fend off invaders. In some species they can be venomous.”
(via Amazing close-up video of Great Barrier Reef animals | Deep Sea News)