Friday 8 June 2012

Deep Sea Dandelion

Image: NOAA Ship Okeanos Explorer
Thermopalia taraxaca, I think


It looks like a spaceship got shot down but it's actually an amazingly strange relative of the jellyfish.

I think the one above may well be Thermopalia taraxaca, spotted at hydrothermal vents near the Galápagos Islands at depths of 2,500 m (8,200 ft). It's a siphonophore, and with a main body some 4 cm (1.6 in) tall, a tiny one.

Like other siphonophores it's actually a whole colony of tiny creatures, each one known as a zooid, and all working together for mutual benefit. The feeding zooids look like those tiny dandelion petals and, I presume, feed on equally tiny crustaceans and such that can be found around the vents.

The world's foremost siphonophore is of course the Portuguese Man o' War. Like this most illustrious relative, the Deep Sea Dandelion has a pneumatophore at the top which lets them float. The difference is that the Deep Sea Dandelion also uses tentacles to tether itself to the sea floor. It's like a hot air balloon that doesn't want to drift too far.

It also has nectophores, which are muscular zooids who devote their lives to enabling the colony to swim.

Dromalia alexandri
Another Deep Sea Dandelion is the sensuously named Dromalia alexandri, which was pictured at a depth of 1,850 m (6.070 ft). That's about everything I know about it, though they appear to do the same "tentacle tethering" thing once they've found a nice place to stay.

So long as that nice place isn't right in the middle of the lawn, they're welcome to it.


TexWisGirl said...

it looks like one of those netted scrubby sponges you use to clean your pores. :)

Joseph JG said...

Haha! It does!

Anonymous said...

Do they sting or are they more docile?

Joseph JG said...

I'm pretty sure they sting only their tiny prey. I have no idea whatsoever how potent they are. I still think that, like the Stalked Jellyfish, this is a flower it's best not to sniff!