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 19, 2018
Question:
Hello, this is Helen C. from Ms. Sheild's 7th Grade Science class, how do they decide which specific place to go to for every expedition? Why did they choose the Brothers Volcano specifically for Expedition #16?
Answer:
We decided to pick this expedition as #16 because we thought people would find it very interesting—it involves a site with complex geology and geochemistry (there are at least two different types of vents at Brothers) and both of those influence the kinds of things that live there. In addition, there will be another expedition going there in May to drill into the volcano and learn even more about what's going on beneath the seafloor. Volcanoes like Brothers that are located in intra-oceanic arcs associated with subduction zones are an important part of the hydrothermal activity that occurs on the seafloor. While many hydrothermal systems have been studied at mid-ocean ridges, those occurring at volcanoes (like Brothers) in volcanic arcs (like the Kermadec), are not as well studied. But they are very exciting as they have different types of hydrothermal activity. Scientists have thought for a long time that it is important to understand the importance of places like this in cycling elements between the earth and the ocean—the question is which volcano do you study from all of those that we know about? In 2012, scientists gathered in Lisbon, Portugal, and identified Brothers volcano as the top candidate worldwide to better understand these hydrothermal systems. A smaller group of scientists then got together and wrote a proposal to the National Science Foundation to go there. And today, here we are! —Susan Humphris
Question:
What is 'Jason' made of that helps him prevent getting crushed under the water pressure underwater? I don't understand how Jason can survive such a huge ton of mass. Thank you. —Jason K.
Answer:
Hey, you guys have the same name! You’re right that Jason has to be strong—that’s why its frame is made of aluminum and critical systems are encased in titanium bottles that are incredibly strong, but also very heavy. The blue and yellow parts that you see in photos are foam, to give the vehicle some buoyancy in the water, but even this is specially designed to withstand the crushing pressures of the deep ocean. It is called syntactic foam, it is made of a very rigid epoxy resin with tiny glass spheres embedded in it. But other parts of Jason are actually designed to be exposed to the pressure. You may have seen a photo from Day 2 that showed part of Jason’s electronic system encased in oil. Because the electronics don’t have any enclosed air spaces, they can’t really be crushed, so we put them in an oil-filled bladder to protect them from the corrosive sea water and to ensure that the pressure, although high, is equal across the entire system. —Matt Heinz
Question:
Hi, I’m in Ms.Sheilds class, I was wondering if it is possible for me to watch a live video while Jason is exploring the sea floor? I know you can watch it on the ship. —Soren G.
Answer:
Hi Soren. Thanks for writing. Unfortunately, we don’t have enough bandwidth from the ship to the satellite and back to Earth for them to stream live video. We have just enough to communicate with them by email and text and to have occasional Skype calls (which don’t require a lot of bandwidth). —Ken Kostel
Question:
I’m am one of Ms. Sheild’s students, and I was wondering how long it takes to prepare for a research cruise? — Joanne Z.
Answer:
Thanks for writing, Joanne. The places that scientists go, whether it's a Dive & Discover expedition or not, is decided first by who gets their grant proposal funded. These proposals, usually written to the National Science Foundation, can take months to complete and often involve dozens of people. Then they have to wait months to learn whether their proposal is accepted. Then they have to begin the planning and scheduling process, first by checking with the University-National Oceanographic Laboratory System (UNOLS) to find out which ships and vehicles will be available where they want to go, and when and when they'll be available. This can often take a year or more for a ship to be in the right place at the right time particularly for remote or seldom-visited locations like Brothers. —Susan Humphris
Question:
Is it possible to lose control of Jason when it's at sea floor? —Bella G.
Answer:
Thanks for writing, Bella. Jason is a complex machine, so anything is possible, but it’s very rare to lose complete control of the vehicle. If the tether or cable becomes damaged, then the telemetry system can lose vehicle contact. In that event, because this vehicle is tethered to the surface, we will make attempts to re-establish a connection. If that is unsuccessful we can pull it up (the tether is a heavy-duty armored cable) and do what's known as a dead-vehicle recovery. —Matt Heinz
Question:
I am a seventh grade Science teacher at Clarke Middle School in Lexington, MA. My students are currently studying evolution, and I had a few questions related to microbes. How do scientists know microbes/ prokaryotes were the first life forms? —Carolyn Sheild
Answer:
If we look at a gene that is shared by all life and has evolved slowly because it has been conserved through evolution, how that gene has changed over time helps us figure out how we are related to each other and how we have diverged through evolution. This gene we use is a gene that is part of the ribosomes. All life has ribosomes, so we can compare ourselves with insects, with plants, with microbes! From that comparison of the gene, how it has changed in sequence helps us reconstruct a family tree of life. And from that tree, you can see that the deeper branches nearer the ‘trunk’ of the tree are all microbes, and we are at the tip of one branch, which we occupy quite closely with chimps and mice and all vertebrates. So microbes are the first life forms. They are the simplest in design. Also, looking at old rocks we have further evidence that the first life on Earth was microbial. Even more cool is—you know what a mitochondrion and a chloroplast is?—well, these are organelles in eukaryotic cells. All have mitochondria, but plants and algae also have chloroplasts. These organelles also have their OWN ribosomes. And if we look at the gene that helped make the Tree of Life, in these organelles their gene maps to the bacterial branch! The chloroplasts, it turns out, are closely related to cyanobacteria (photosynthetic microbes that make oxygen and fix carbon dioxide)! So some time during evolution, an ancient cyanobacterium was engulfed (taken up) by a eukaryotic cell (like an amoeba). It wasn’t eaten, but then evolved to become a fixed organelle, and help the new eukaryotic cell do photosynthesis—et VOILA… there was your first plant-like cell! —Anna-Louise Reysenbach
Question:
Is it based on the premise that simpler life forms came before more complex ones? —Carolyn Sheild
Answer:
A bit like that, but also based on the above discussion, and on what we know the early Earth was like, and what biochemical fossil records were preserved in the early Earth rocks. —Anna-Louise Reysenbach
Question:
Did Archaea or bacteria come first evolutionarily? —Carolyn Sheild
Answer:
We don’t know that. The first was a simple cell that split into the a main domains Archaea and Bacteria. We are more closely related to Archaea. —Anna-Louise Reysenbach
Question:
Also, if you could, please describe the DNA & RNA similarities and differences, in language that may be understandable by educated middle-schoolers if possible. —Carolyn Sheild
Answer:
Start thinking Central Dogma. DNA makes RNA makes Protein (enzymes)
DNA is the genetic code for all life. It is double stranded, it codes for all the POTENTIAL functions of the cells. It has AGCT, and the sugar in its backbone is deoxyribose.
RNA: When the genes in the DNA are ‘read’, they are read (transcribed) to make RNA. There are many kinds of RNA. The key ones are messenger RNA (mRNA, which will then be read (translated) to make protein), transfer RNA (tRNA, which helps the ribosome to read the mRNA, to make protein) and ribosomal RNA (rRNA, which is integral for the ribosome to function). RNA is SINGLE stranded, and contains AUGC, and a different sugar backbone. When mRNA is made from a gene, it means the cell is getting ready to actively use that the function encoded in that gene. When the mRNA is translated to protein, the function can happen. —Anna-Louise Reysenbach
Question:
I am one of Ms. Sheild’s students and I am learning evolution right now, so I am wondering if the organisms that live in those extreme environments evolve something special to survive? —Alex F.
Answer:
Great question. Incredible that some of these microbes can grow over 100 degrees Celsius ( try figure out what that is in F) and some cannot grow below 70 degrees Celsius (?F). So these microbes, the highest temperature ones are all Archaea, have several ways they thrive at high temperatures. One common thing is they have very stable cell membranes. So if you remember, the backbone of the membrane are lipids (like oils/fats). So if you heat them up, they become more fluid, less viscous, like oil/fats do (just thinking about trying to get a greasy stain out of your T-shirt, it’s easier to remove if you use the hot cycle in washing machine). So heat loving microbes, or thermophiles, have membranes that are often only 1 solid layer (not a bilayer membrane), and the lipids in their membranes are called tetraether lipids, which make stronger membranes. So thats one example—their membranes are stronger. They also make some small changes in their proteins, so their proteins don't fall apart when they are heated. Some have special proteins, that help keep their DNA stable at high temperatures too. So the DNA doesn't fall apart which it will without these.
Question:
What tests and experiments do you run on the samples you collect and what tools do you use for them? —Anna Maria K.
Answer:
Hi Anna, great question! So the microbiologists are trying to grow some of the organisms from Brothers in ovens on the ship, and are also extracting DNA from the samples so they can identify what organisms inhabit Brothers. The geochemists are analyzing the hot water (fluids) using pH meters to measure how acidic the fluids are, and more complex instruments like the gas chromatograph (GC) which measure which gases are present (hydrogen, methane, carbon dioxide). The geologists are describing the minerals in the chimneys. The geophysicists are using thermal blankets and heat flow probes that they push into the sediments, to see how hot the rock is at depth and how it relates to the magma chamber beneath the volcano. They also did some mapping of the seafloor using a magnetometer to measure magnetic field of the seafloor which shows where the rocks have been altered by the acidic hydrothermal fluids. This shows the extent of the activity over time.
Question:
Hi I’m from Ms. Shield’s class! I was wondering what you usually eat on your two week long expedition. —Izzy A.
Answer:
Whoaaah! We seem to always be eating. Between meals there are lots of snacks available: chocolate, chips, nuts, cheese, lots of soda etc. We have 3 meals a day, and the 2 cooks on the ship vary those a lot. But breakfast we get your usual eggs, bacon and toast, but then also treats like pastries, lots of fruit, yogurt. That’s from 7 ish to 8. Lunch is from 11:30 to 12:15 and always includes a big salad bar, plus often 2 proteins, like chicken and fish, and lots of vegetables, pasta, always a dessert or sweet something. Dinner is from 5-6 and a bit more elaborate maybe, but similar to lunch.
Question:
I am in Ms. Sheild’s seventh grade class. I understand that plate tectonics causes the formation and destruction of volcanoes but why did Brothers Volcano collapse in on itself and the other volcanoes didn’t? Also can the gold in the hydrothermal vents be harvested? —Adi K.
Answer:
Neat question. So apparently one reason for the collapse creating a caldera is that the hot molten lava gets sucked back into earth’s crust, sort of like a piston functions in a car.
There are trace amounts of gold, but not enough to harvest. But the copper and similar minerals are in very high concentrations, so some mining companies are exploring ways to harvest these. As you can imagine trying to do that at more than 1500 meters depth is not easy technology! (It would be good for you to convert the meters to feet for your classmates.)
Question:
Hi! I’m in Ms.Shield’s class and I was wondering How do the heat and pressure of the hydrothermal vents affect the marine biology? What is the tallest hydrothermal vents and how tall is it? Thank you for taking your time answering my question. —Anna H.
Answer:
Heat definitely affects the animals. They occupy zones where they can tolerate the heat. If you see the shrimp, the little white patches on their backs, can sense black-body radiation (high heat). There are some worms that make tubes on the hot rocks, so they can withstand higher temperatures than 37 degrees C. The crabs move quickly away when they feel the heat. Of course the microbes LOVE the heat, and are the slimy white stuff you see on the chimneys.
Pressure does affect the animals. Especially animals that have gas spaces in their body. Some are more sensitive than others. Some experiments that biologists have done is to quickly put the animals back at high pressure (in high pressure ‘aquaria’) when they come on board to study how they function in these high-pressure vessels. Many microbes can withstand the pressure differences, but if you think about it, things like gases will be different (like their solubility) under pressure. Its really difficult to do any high pressure experiments, so we only have a limited understanding of the pressure effects on life in the deep-sea.
A hydrothermal vent is like a geyser, where very hot fluid comes out of the seafloor. Ask you teacher where that hot water came from, what path it had travelled before coming back to the sea floor. Anyway, when that hot fluid mixes with cold seawater, the minerals precipitate out of solution, and make the chimneys. At Brothers these chimneys can be about 20 meters tall! but they are spindly, so eventually they break and fall to the seafloor. The tallest one ever measured was called Godzilla. It was 80 meters or so tall (how many apartment stories is that?), and was in the Atlantic Ocean. It eventually came down too.. probably after a small seismic event like an earthquake.
Some of the chimneys here at brothers can grow at 4cm/hr. How much is that in inches?