WEBVTT

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Hi, guys! Welcome on board.

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They said, “finally, we’re so seasick.”

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Here they are. That’s what we’re after.

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What we’ve done in the past is just do a very simple study on shell thickness.

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Yeah. The shells are notably weaker. So these are really thin.

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So that’s been our past work which has now brought us back,

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because we realize that these are, it’s a little miracle that they’re even living here.

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They’re living in places that you would normally think are hostile to them because of the low pH that dissolves shells,

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but they have a way of protecting themselves and keeping their shells from dissolving by apparently building up a thicker organic layer on the outside of the shell.

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The secret here is that these animals are struggling to keep themselves completely protected from the waters by their coat, a little gold coat on the outside.

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If we removed this yellow, it’s called the periostracum. It’s an organic coat over the top.

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If we just scrape that off, you’d see the white shell underneath.

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But all of this white stuff, the calcium carbonate, is completely covered by either animal tissue on the inside or this gold layer on the outside.

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So it’s never seeing seawater.

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And what we’ve found is that the moment any white is exposed, it dissolves immediately in these pH waters.

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You see this really extreme case here at NW Eifuku where you have nearly pure CO2 coming out,

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and that’s really driving all the chemistry at that volcano.

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So it’s quite interesting that we use those volcanoes to study maybe how animals can adapt to lower pH or which species will survive,

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to get a peek at what the future ocean might look like.

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Because of all the building CO2 in the atmosphere, the pH of the surface ocean is dropping by about 0.2 pH units per 100 years.

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A big concern has been what we call ocean acidification.

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So as CO2 goes into the water, it changes the whole balance of the carbonate chemistry.

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This particular species of mussels that we find at this volcano is adapted to living in low pH, high CO2 environments.

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In fact, they only are in the low pH environments because that’s where they’re getting their energy from.

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They’re getting their energy from chemosynthetic organisms that are symbionts  within the mussels that take advantage of

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the hydrogen sulfide and other reduced compounds that are in the plumes that are coming out of these vents.

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So this is the big gill. The big brown thing is the great big gill that has all the symbionts inside it. So that’s how it makes its food.

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So they’ve got this tradeoff. It’s a really great place to live for their food source, which comes from the bacteria.

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On the other hand, it’s a lousy place to live if you want to make a shell.

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It’s a tradeoff. Everything in life’s a tradeoff, right?