CTD stands for conductivity, temperature, and depth.
By measuring those three things, we can tell a lot about the seawater.
We can calculate a lot of other information about it.
For example, the salinity, how salty it is.
What’s most important about the CTD for our purposes is that we put additional sensors on it,
like the light scattering sensor, which measures for particles,
the oxidation reduction potential sensor, or ORP, which is an indicator of the type of chemistry.
Oh! There we go! There’s an anomaly. We’ve got high particles, low oxidation reduction potential, and a decrease in pH as well.
So what we know from this is that the volcano is still active.
They were doing a coral reef survey around the coast of that island and they were hearing underwater explosions for Ahyi,
which is right under us here. Because Ahyi was erupting, they could hear it over there.
They could even hear the booms through the hull of the ship, which is pretty amazing.
For now, we’re just collecting some baseline data so we know what’s happening here
and then we’re going to further northwest to NW Eifuku, our next Jason dive site, another seamount about eight hours further north.