Expedition 16 Mail Buoy

Here is your chance to ask questions directly to the scientists, engineers, and crew members aboard the R/V Thompson. We will answer your question directly to the email address you provide, and we may also post your question with its answer right here.

Thanks for following along!

Mail Buoy: March 22, 2018

Question:

How hot is an average volcanoes magma? —Kennedy

Answer:

The temperature of magma depends on its chemical composition, but in general, magmas range in temperature from 800-1200°C (1470-2190°F). —Susan Humphris

Question:

How much technology do you have to use to record the expedition? —Amelie

Answer:

There are a lot of different types of data recorded during a cruise, ranging from environmental parameters collected on the ship, such as sea surface temperature and salinity, to images, data, and samples collected from the seafloor with the ROV Jason. All the data are recorded on hard drives (with backups, of course!) and returned to shore. They are then deposited in different databases depending on the type of information. For example, the images, both still and video (up to 4K), collected with Jason are stored at Woods Hole Oceanographic Institution in an archive of data and samples collected with vehicles that are part of the U.S. National Deep Submergence Facility. After a brief time of access limited to project participants, the information becomes available and searchable by the entire scientific community. —Susan Humphris

Question:

As a volcanologist, what new things do you learn from hydrothermal vent systems that you aren't able to find at more traditional volcanoes? Since both can occur at a any plate boundary, their mineral content can both vary. I am very interested in pursuing hydrothermal vents as a more focused study beyond graduation at Scripps, WHOI, or MBARI. I wonder most about the existence of hot spot vents, similar to Hawaii, whose chemical and mineral content come from a much deeper magma source than divergent, or even subduction zone, vents. How rare is it that we have an opportunity to study or "sample" anything from that depth? I am eager to hear back from you and would love to hear your insights, suggestions, or otherwise 🙂 —Bobbie

Answer:

Glad to hear there is a budding volcanologist out there! I wish you luck with your studies! One of the main lessons we have learned from studying seafloor hydrothermal systems in different types of volcanoes is that, despite the main ingredients being similar (seawater and volcanic rock), there is great variability in the results of their interactions. It appears that hydrothermal systems near or associated with subduction zones are often more influenced by exchange of elements and gases with the volcano’s magma chamber  than those on mid-ocean ridges. This has significant impact on the transport of metals to the seafloor and the formation of mineral deposits. Brothers volcano is unusual in having both types of hydrothermal systems within a single caldera - how this is possible is what we are studying on this expedition.

As for hotspot vents--despite the magma source being much deeper--we see mostly the interactions of seawater with the shallower layers of the Earth’s crust. Take a look at information on the Loihi Seamount hydrothermal system that is part of the Hawaiian chain. —Susan Humphris

Question:

I’m in Ms. Sheild’s class and I was wondering approximately how many hydrothermal vents are there around the world. Thank you for your time 🙂 —Miu

Answer:

Good question--and one for which we do not have a good Answer: yet! To date, more than 500 hydrothermal vent sites have been discovered on the seafloor around the world. However, as you probably know, only a small percentage of the seafloor where vents might occur has been studied so there are likely to be many more. —Susan Humphris

Question:

I’m in Ms. Sheild's class, I was wondering why it’s important to know the architecture of the the volcano vent system, besides knowing where to drill? —Zoe

Answer:

Studying the architecture of the volcano and its hydrothermal vents systems allows scientists to learn about how volcanoes are built and then change as seawater circulates through their upper layers to create hydrothermal vents and mineral deposits. Until seafloor vents were discovered, geologists who worked on ore deposits had to study mostly old, dead systems and then deduce how they are formed. Now they can “watch” mineral deposits being formed at the bottom of the ocean! —Susan Humphris

Question:

Hi I’m from Mrs. Sheild’s class. How do you find these underground subduction zones?

Answer:

Subduction zones occur where two tectonic plates are moving towards each other and one slides beneath the other, so the edges of tectonic plates are a good place to look. But what do you look for? As one plate dives under the other, a deep trench is formed that can be detected by research ships collecting seafloor depth data. Perhaps you have heard of the Mariana Trench, the deepest part of the ocean where, in 1960, Jacques Piccard and Don Walsh descended to a depth of 10,915 meters (6.8 miles) in the bathyscaphe Trieste. See if you can find the Mariana Trench in the Western Pacific on a map.

Question:

I'm in Ms. Sheild's science class at Clarke middle school. Question: is: Is it hard to sleep on the boat because of all the noise from the engine and the water moving the boat around? Thank you! —Anna

Answer:

Great question, Anna. For some people, the motion and noise make it very difficult to sleep. For others (like me), however, those things make it easier to sleep. It feels like being rocked to sleep with white noise playing all around you. Sometimes. On one cruise I was on, the crew was working on a part of the ship right above and outside my room for several days, chipping rust off the bulkhead and painting. Of course, they had to work during daylight hours, but I was working most of the day and night and was sleeping early in the morning when they started working. That made it difficult to sleep. It’s also difficult to sleep during Jason dives if your room is toward the front of the ship because that’s where one of the thrusters is located that keeps the ship precisely positioned while the vehicle is in the water. Every so often the navigation computer determines that the ship needs to be moved a couple of feet east, for example, and it fires up the thruster and everyone sleeping nearby wakes up, no matter how deeply you sleep. It’s very loud.

Question:

What are the biogeochemical processes that sustain the ecosystem at the Brothers Volcano? —Random Person

Answer:

On land, ecosystems are sustained by plants conducting photosynthesis and using energy from the sun to turn carbon dioxide into biomass. At deep-sea hydrothermal vents like those at Brothers volcano, the ecosystem is sustained by bacteria and archaea conducting “chemosynthesis” – using energy from, not the sun, but chemical reactions to turn carbon dioxide into biomass and form the base of the food web.

At most deep-sea hydrothermal vents, including those at Brothers, the most common chemosynthesisers are sulfide-oxidizing bacteria. These bacteria take hydrogen sulfide (H2S), which comes out of vents, and combine it with oxygen from the ocean to form sulfate (SO4). They can use energy released from this reaction to fix carbon dioxide. This is the most common kind of reaction because there is a lot of sulfide and a lot of oxygen. Some microbes are iron-oxidisers – they also use oxygen, but they take reduced iron (Fe2+) and turn it into “rust” or oxidised iron (Fe3+).

However, we also see other chemosynthesizers in vent systems. Where there is no oxygen – at high temperatures in the rocks around vents and in vent chimneys – bacteria and archaea tend to use hydrogen to perform “reducing” reactions. They can turn iron from “rusty” oxidised iron into black reduced iron minerals, and sulfate or sulfur back into sulfide (H2S), and make methane (CH4) from hydrogen and carbon dioxide. All these reactions provide energy and allow them to create biomass. Which biogeochemical reactions are performed at different parts of vents depends on how hot it is, which gases and minerals are available for bacteria and archaea to use in these reactions, and what the pH is. As hydrothermal vent microbiologists, we have to study not only the microbes but the chemistry and geology of these systems to understand which reactions are being performed and how much biomass they can create. —Anna-Louise Reysenbach

Question:

Hi, I am from Ms. Sheild’s class and I was wondering whether the scientists on your ship think that there is another possible first organism on earth that came before Archea that we have not discovered yet? —Maxim

Answer:

The first organisms on Earth were definitely not archaea as we know them today. Instead, they were organisms very much like modern bacteria and archaea, which did some of the same things, but were the ancestors of both and different to them. It’s like mammals – we know from fossils that the first mammals looked something like modern shrews, but they were the ancestors of all mammals and not exactly the same as any mammal living today.

Because, unlike animals, microbes don’t leave fossils of themselves (only fossils of things they have changed around them, like minerals they have created) we can’t know exactly what the first organisms on Earth were like. However, we can look at the DNA of archaea and bacteria and see which genes are shared by every species. If a gene is shared by all modern bacteria and archaea, it must have been present in the last ancestor of all of them. The set of genes that we know were present in this “Last Universal Common Ancestor” (LUCA) tell us that it probably lived in hot environments without oxygen, maybe deep-sea hydrothermal vents. So in some ways it would be like modern archaea that live at hydrothermal vents.

However, LUCA would have been different from modern archaea in other ways that we can’t necessarily know about, because we don’t have one to study. Instead, scientists do experiments to figure out what the minimum number of genes (and parts of their cells) is that microbial organisms need to live and reproduce. The very first true organisms were probably very simple, much simpler than modern archaea, because archaea have had four billion years longer to evolve and adapt to their environment. And before the first true organisms, we think that DNA molecules copied themselves without cells to live in – then eventually it evolved membranes to protect itself from the environment, and those were the first cells. In some ways, life – including you and me - is just a way for DNA to efficiently reproduce itself! —Lucy Stewart

Question:

Hi, Thank you so much for Answer:ing Question:s, as well as many from my students. Anna-Louise: I was wondering if you could please describe the DNA & RNA similarities and differences between Archaea and bacteria? Thank you. (Sorry my earlier question was unclear- I know the differences between DNA and RNA!) Thank you again for your time, and best wishes on your expedition. —Carolyn Sheild

Answer:

No major differences in the RNA and DNA between the two. Just different gene content. —Anna-Louise Reysenbach

Question:

How did you create your machines to prepare for a volcano or an earthquake? —Emilee

Answer:

The short answer: is that our equipment won’t be affected by a volcano or an earthquake, so we don’t have to make any adjustments to our machines to prepare for such natural disasters. Most of our equipment, including our remotely operated vehicle JASON, is attached to the ship the whole time the equipment is in the water, and can be pulled back onto the ship in bad weather or, in extremely rare cases, major earthquakes. And the volcano we’re looking at on this cruise will not be erupting (at least, not in our lifetime) and so we don’t need to worry about that either. Thanks for your question! —Sam Nadell

Question:

How deep in the ocean does Jason go down to see the vents? —Jack

Answer:

Thanks for your question, Jack. The vents at Brothers volcano are about 2,000 meters (6,560 feet) below the surface, but Jason can dive as deep as 6,000 meters (19,685 feet). —Ken Kostel

Question:

Hi, this is Edie from Ms. Sheild’s science class. How did you name Jason and Medea?

Answer:

Thanks for your question, Edie. Jason and Medea are named for the adventurous ocean explorer of Greek mythology and his wife. —Ken Kostel

Question:

Hi, I’m from Ms. Sheild’s class, and I was wondering how you choose the names for the ROVs and ships? —Ryan

Answer:

The ROVs (and all the underwater vehicles) have been named by the people who built them, but there’s no formula for naming them. Jason and Medea, for example, are named for the adventurous ocean explorer of Greek mythology and for his wife. The submersible Alvin was named after its designer, Allyn Vine. One of the early autonomous (robotic) underwater vehicles was named ABE (Autonomous Benthic Explorer). Ships are a little different. The U.S. research ships are named by the Navy (because the Navy owns them and they are officially Naval vessels), but usually at the suggestion of the institution that operates the ship. R/V Thomas G. Thompson, for example, is operated by the University of Washington and is named after Thomas Gordon Thompson, a scientist who used to work at the university who was the first chemist to focus on the chemistry of seawater. R/V Atlantis, the ship that is operated by WHOI to support Alvin, was named after the first ship in the U.S. that was built specifically to do oceanographic research (which was also owned and operated by WHOI and is the same ship that the space shuttle Atlantis was named after). The two newest ships in the U.S. research fleet, Neil Armstrong and Sally Ride, were named by the Navy to honor U.S. astronauts. —Ken Kostel