This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Of the ocean’s many beautiful oddities, the dandelion siphonophore is one of the finest. What you are about to see is the tuft of feeding tentacles and anchor cables of an organism that looks like it would be at home perched atop a truffula tree.
Watch the video here.
This year the two ocean exploration ships Okeanos Explorer and Nautilus have uncovered a variety of interesting siphonophores, including this stunning dandelion, a type of siphonophore distinguished by its attachment to the seafloor.
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Siphonophores have similar gigs to their jellyfish and coral kin in the phylum Cnidaria: stinging and eating things. However, their appearance is quite different. Rather than a single naked medusa or a colony lodged inside a fortified skeleton, siphonophores are naked colonies of Siamese twins. They are not identical, though. They usually specialize in a particular task and contain only the anatomy necessary to perform that function. Some push the colony forward, some catch and eat food, and some make little siphonophores.
Okeanos Explorer, which took the first video, sighted another dandelion siphonophore this summer that appears to have an adaptation I have not seen before: a system of retractable and reusable fishing lines suspended from the anchor cables. I have never seen anything like this before. As one of the commentators says, it’s mesmerizing.
Of course, part of what makes dandelion siphonophores so weird is that they are tethered to the seafloor and relatively small. Most siphonophores drift in long chains.
There were at least two sightings of drifting siphonophores this year too. Here’s one from the Nautilus that looks like a bunch of dandelion siphonophores strung together like beads on a string -- or, as the watch points out, a feather boa:
And here’s another sort of drifting siphonophore from Okeanos Explorer that looks quite different to the last one. In this one, you can really see the division of labor. The clear individuals in the front do the driving, and the pink ones in the back do the eating.