What do Donald Duck and underwater volcanoes have in common? Helium!
Helium is a noble gas, and it’s playing a particularly noble role on this trip. It is one of the most important elements to find on any successful hydrothermal hunt. The Helium-3 isotope has been present since the formation of earth, but the only source of it currently is that which is degassing from the Earth’s mantle. When we find this unique isotope, we are sure that it is being released by hydrothermal activity and volcanic eruptions. As a noble gas, it is not involved in any chemical or microbial reactions, ensuring its presence in seawater over much longer distances than any other hydrothermal marker. This makes it an excellent tracer for deep ocean circulation studies. Unfortunately we cannot analyze this using tools on the ship, but it will provide a vital part of the hydrothermal picture of the Mariana back arc when we get our results in a few months time.