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Images: Big Questions About Tiny Bacteria

Jesse McNichol is a Ph.D. student in the MIT-WHOI Joint Program in Oceanography. His research focus is on a class of microbes called Epsilonproteobacteria, which thrive at seafloor hydrothermal vents—a volcanic, high-pressure, low-oxygen, completely dark environment that resembles conditions that existed early in Earth's history. So these microbes could provide clues to the origins of life on our planet. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
The research team's study site is 1,000 miles off the coast of Panama on the East Pacific Rise, a section of the volcanic mid-ocean ridge system that separates individual tectonic plates such as the Pacific, Cocos, Nazca Plates. Hydrothermal vents are often found in these volcanic areas on the seafloor. (Eric S. Taylor, WHOI Graphic Services)
As hot fluids spew from hydrothermal vents, they hit the cold water at the bottom of the ocean, and minerals dissolved in the fluids precipitate out as solids. Over months and years, the minerals gradually build up to form tall columns, or chimneys. Huge numbers of microbes live within the rocky walls and on the outside surface of the chimneys. The inside of a chimney is too hot, even for the hardiest of bacteria. (Photo courtesy of Stefan Sievert, WHOI/NSF/ROVJason©2014 Woods Hole Oceanographic Institution)
A piece of a hydrothermal vent chimney sampled by the remotely operated vehicle Jason shows interior channels through which hot fluids vent out from the seafloor. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
In deep sea, pressure can reach 3,500 pounds per square inch. To sample fluids (and microbes in them) at these depths, WHOI scientists and engineers invented a device called an “Isobaric Gas-Tight sampler” (IGT). Made of a titanium cylinder, it can suck in bacteria and fluids and then maintain the intense pressures of the deep sea inside the cylinder as it journeys all the way back to the surface. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
In a lab aboard ship, Jesse McNichol his colleague, François Thomas, used the IGTs retrieved from the seafloor as incubation chambers to conduct experiments on vent microbes inside. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
WHOI electronics technician Casey Agee helps load instruments onto a platform in the front of the deep-sea vehicle Jason. The remotely operated vehicle will use them to collect samples and conduct experiments at the seafloor. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
A tether links the deep-sea vehicle Jason to the research vessel Atlantis. Sensors and cameras on Jason transmit video and other data via the tether to researchers aboard ship, who relay commands back down the tether to operate the vehicle. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
In the Jason control room, a wall of video screens displays images sent from high-definition cameras on the vehicle at the ocean floor far below to observers and a pilot operating the vehicle. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
After the Isobaric Gas-Tight samplers do their job, they are retrieved from the seafloor and brought back on deck, where Stefan Sievert, chief scientist of the expedition and Jesse McNichol's Ph.D. advisor, rinses off corrosive salt water. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
In a lab aboard ship, (from left) graduate student Jesse McNichol, WHOI geochemist Jeff Seewald, and research technician Sean Sylva inspect a device used to remove vent
fluid (and the bacteria inside it) from an Isobaric Gas-Tight sampler without releasing the pressure inside. (Photo by Jen Barone)
Jesse McNichol and colleagues conducted microbiological experiments aboard ship. He incubated the Isobaric Gas-Tight cylinders containing vent fluids, allowing the bacteria inside to grow as they normally would on the seafloor. Then he removed small amounts of fluid from the device to test the changing chemistry inside and added other chemicals, including hydrogen gas, nitrate, and oxygen, to learn which ones the vent microbes might use as “fuel” to survive and grow. (Photo by David Levin©2014 Woods Hole Oceanographic Institution)
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