could you PLEASE tell us more about giant tube worms
I would love literally nothing more
Essentially these guys
(Riftia pachyptila specifically) are fucked up for a variety of reasons. They live pretty much directly in the stream of superheated water coming out of hydrothermal vents in the deep sea, an environment that is not only hostile because of the super fucking hot water, but also the high concentrations of sulfides (toxic shit) in said water, and also there’s no goddamn light, so no algae or other photosynths that kick off the food chain in most of the ocean. Even most deep-sea fishes are connected to the surface, they eat shit that falls down, whale falls, marine snow, or they eat other fish that migrate to and from the surface (depending on how deep we’re talking). Nothing should be able to live here, except maybe the odd extremist bacteria (or archaea).
But they do so, that theory’s out.
The most pressing of reasons why they’re fucked up, though, is that they don’t have a mouth, or a gut, so they can’t really... Eat. They weren’t the first mouthless, gutless worms to be found, but the others were all small enough that they pretty much just figured they diffused nutrients in through their not-quite-skin, but these bitches are huge, and the surface-area-to-volume-ratio (every bio professor I’ve ever had is obsessed with surface-area-to-volume-ratio) was too large for that to be feasible.
Noooow I get to talk about the trophosomes.
So the trophosome is a big fuckin organ that takes up most of the length of the worm. It’s kinda spongy, real lobular, and obviously important. They exist in other worms, but were thought to feed the gonads during gamete development. But they found something in these guys’ that kind of negated that theory.
Sulfur!
That’s what those little yellow dots are: pure, crystalized sulfur. This is a cross section of a Riftia pachyptila trophosome, taken from a presentation given by the lady I’m about to talk about. (It’s on youtube here, if you wanna watch 20 minutes of worm talk like I did)
They still didn’t know what the trophosome did, so they theorized that it could have acted like a filter, because hydrogen sulfide in particular is toxic to most life forms, and there’s a lot of it here.
That’s where...
She comes in! Her name is Colleen Cavanaugh, and she was an undergrad at Harvard at the time of the initial research, and she heard about the worms, the trophosomes, the sulfur. And SHE basically knew what the fuck was going on from when she listened to the original researcher (Meredith Jones, of the Smithsonian Institute) talk about it, so she convinced some people to get her a hunk of worm. As you do.
After studying said hunk of worm for a while she basically said ‘yeah, I was right, get fucked, check it out:’ The worms house chemosynthetic endosymbiotic bacteria in their trophosomes, bringing stuff in through the plume, (the red bit at the top, functions kind of like a lung or a gill) that looks like this:
And basically that’s what makes these guys so funky, they not only have endosymbionts, which exist in other worms we know of now, but weren’t aware of at the time, but theirs are also chemosynths: they oxidize/metabolize hydrogen sulfide as an energy source. The pure sulfur in the trophosome was the waste product. (chemosynthesis generally looks like this:
though i’ve seen some slight variations of the formula. This one is from Pearson education.)
The bacteria get oxygen and hydrogen sulfide from the worm breathing it in, CO2 from the waste of the worm’s own cellular respiration, and are osmotically protected, basically they have a safe home inside their worm pal. The worm, then, is protected from the toxicity of H2S, because the bacteria are turning it into pure sulfur which is NOT toxic, and they feed off of the food the bacteria make for themselves (and the worms).
So like goddamn how can you NOT love giant tube worms.
