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January 21 responses:

What kind of bacterial species live at these vents?

Amanda Meyer
Memorial High School, Eau Claire, Wis.

Hi Amanda,

Bacteria living at these vents have to adapt to very extreme conditions ranging from refrigerated waters (3°C or 37°F) to very hot and toxic (more than 85°C or 185°F) hydrothermal fluids that have very little oxygen. Most life would suffocate in the absence of oxygen, but these microbes thrive without it. Some of these microbes are chemosynthetic—meaning that they can harvest energy from inorganic chemicals that dissolve out of the rocks under the sea floor. There are many types of chemosynthetic microbes. Because there are so many kinds of bacteria in the vents, we still don’t know all of the types that are there.

Ileana Pérez-Rodríguez

How many species of microbes have you gathered so far? Do all deep sea bacteria use chemicals for energy?

Andes & Charlie
Ms. Sheild's classes at Clarke Middle School, Lexington Mass.

Hi, Andes & Charlie,

In my research, I personally have gathered eight or nine different microbes from vents that I can grow in the laboratory. In the past, I even found two new bacterial species from deep-sea vent environments. They both like environments that are relatively hot—one lives in vent fluid that stays around 45-60°C (113-140°F), and the other lives in fluid closer to 75-85°C (167-185°F). They also prefer environments with little or no oxygen, and with lots of sulfur. There are many other types of microbes at the vents with unique lifestyles. On this cruise, we’re looking mainly at one particular type of microbe, called an “epsilonproteobacteria.” We’ve taken samples of microbes like these, but it will take a few months to analyze them and find out for sure what they are.

As for what bacteria use for energy: Not all bacteria in the deep sea are chemosynthetic, but all bacteria down there technically use chemical energy to survive. The main difference is whether those chemical nutrients come from inorganic sources (meaning they've dissolved out of the rocks below the sea floor), or from organic sources (meaning they're bits of other living things). If you think about it that way, even humans exist on chemicals—when we eat food, our stomachs break it down into the chemicals our bodies need to survive.

Ileana Pérez-Rodríguez

Do acoustic sensors on the submersible Jason ever detect any (new or unusual) sounds?  If so, do they know the source of the sound?

Justice
Ms. Hummelsheim's Robotics class at Palmyra Middle School
Palmyra, Missouri

Dear Justice,

Thanks for your question. The only time we’ve ever had acoustic sensors on the vehicle was when we were observing live volcanoes a few years ago. In that case, we used them to sense the explosions they created (which we heard very well), and we already knew the source of the sound.

Tito Collasius
Jason Expedition Leader

[P.S. from the editor—Although Jason doesn’t usually carry acoustic sensors, other robotic devices do. For example, scientists at WHOI are equipping autonomous gliders with acoustic sensors that can detect whale calls. You can read more about them here: http://www.whoi.edu/oceanus/feature/call-of-the-whales. Other scientists have found that sensors set on the seafloor to detect undersea earthquakes also pick up the sounds of whales. Read more about that here: http://www.whoi.edu/oceanus/viewArticle.do?id=161069.]

What materials is the body of the submersible Jason made out of?   We are curious because we know it has to withstand extreme pressure and temperatures.

Gaige
Ms. Hummelsheim's Robotics class at Palmyra Middle School
Palmyra, Missouri

Dear Gaige,

Good question. Jason is built of syntactic foam, a buoyant material made out of tiny hollow ceramic beads.  It also has an aluminum frame, a lot of titanium pressure housings for the equipment on board, and a little bit of stainless steel holding it all together. There’s also a bit of rubber in there to isolate different materials.

Tito Collasius
Jason Expedition Leader