WEBVTT

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CTD stands for conductivity, temperature, and depth.

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By measuring those three things, we can tell a lot about the seawater.

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We can calculate a lot of other information about it.

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For example, the salinity, how salty it is.

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What’s most important about the CTD for our purposes is that we put additional sensors on it,

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like the light scattering sensor, which measures for particles,

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the oxidation reduction potential sensor, or ORP, which is an indicator of the type of chemistry.

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Oh! There we go! There’s an anomaly. We’ve got high particles, low oxidation reduction potential, and a decrease in pH as well.

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So what we know from this is that the volcano is still active.

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They were doing a coral reef survey around the coast of that island and they were hearing underwater explosions for Ahyi,

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which is right under us here. Because Ahyi was erupting, they could hear it over there.

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They could even hear the booms through the hull of the ship, which is pretty amazing.

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For now, we’re just collecting some baseline data so we know what’s happening here

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and then we’re going to further northwest to NW Eifuku, our next Jason dive site, another seamount about eight hours further north.