January 12, 2014 (posted January 13, 2014)
by David Levin
On some days, taking a shift in the Jason control van feels like setting out on an epic road trip. Scientists, pilots, and technicians trade jokes from their seats as the vehicle glides along the ocean floor. There’s often music playing, providing a soundtrack to our exploration, and on a good night, the team dips into a secret stash of chocolates kept behind a loose panel near a row of video monitors. It looks like the ultimate Sunday drive.
Jason’s pilots make their job seem easy—but in reality, some of the maneuvers they perform on the ocean floor challenge even the most seasoned pro. Picking up samples of vent chimneys, deploying scientific equipment, and grabbing delicate animals are just some of those tasks. These videos take you below the surface with Jason as the remotely operated vehicle performs its most delicate work.
The fragile pillars you’ll see in this video may look strong, but they’re really a loose collection of minerals that build up gradually as the ultra-hot fluids venting out of the seafloor react with cold seawater. As they grow, they provide a home for microbes, which live both on the surface of the pillars and in tiny spaces inside their walls. In order to study these organisms and understand how they colonize the vents, scientists carefully break off chunks of the chimneys and bring them to the surface. It’s not easy—as you’ll see, when Jason pilots try to grab the structures with the ROV’s robotic “hands,” the pillars seem to explode into the water. As Jason Expedition Leader Tito Collasius puts it, “It’s like trying to grab a handful of sand with three fingers.” Here, you can get a sense of just how hard it is to get a good sample. Watch two unsuccessful attempts, followed by one that went perfectly.
Sometimes leaving equipment at a vent site can be just as hard as collecting pieces of a chimney. Here, Costa Vetriani, Donato Giovanelli, and Ashley Grosche are doing just that. You’ll see Jason deploy one of their samplers, called a “colonizer,” on the sea floor. The device (which we learned about on January 7) is simple—just a piece of plastic pipe with some metal screen on top—but it can be tricky to handle. The scientists need to place it precisely where diffusely-flowing vent fluid is coming out of the sea floor, so it will be in the path of microbes carried by the fluid. The researchers hope to learn how microbes first settle on a surface at a vent site. If you watch closely, you can see two different kinds of tubeworm in this video. Tubeworms offer clues to where hot fluid is coming out of the seafloor. The worms on the left, called Riftia, prefer a cooler environment than the smaller Alvinella worms in the center.
As we learned on January 8, the scientists aboard the Atlantis are after more than just microbes living in the vents themselves. They’re also interested in microbes that have a symbiotic relationship with other vent animals. These Riftia tubeworms, for example, have a nice deal worked out—they provide bacteria living inside them with chemicals from the vent fluid, and the bacteria in turn make nutrients for their hosts. There’s a trick to collecting a tubeworm sample without damaging it, however. If Jason’s pilot taps the worm, it will duck down inside its protective tube to hide—giving the pilot a chance to grab the tip of the tube without crushing the worm inside. Once the worm is plucked from the rocks, time is of the essence. If the worms are stressed for a long period of time, they will send out hormones that change their overall body chemistry, making it difficult to analyze them in the lab. For that reason, researchers must send them up immediately on an elevator, as we’ll see in the next video.
This clip offers a rare view of samples leaving the ocean floor on an elevator. This one carries with it two white plastic “bioboxes” that hold fresh tubeworms and mussels collected by Jason. On the left side of the elevator, you’ll also see a plastic milk crate full of basalt samples (lava rocks from the ocean floor), and in the background, the grey pressure cylinders of Jeff Seewald’s IGT samplers. Watch as Jason releases the weights that hold the elevator down, letting it rise gently toward the surface. (To learn more about elevators, check out our dispatch from January 5.)
Today's Weather
Sunny
Lat: 9° 50.304 N
Long: 104° 17.469' W
Winds: NE; 16.7 knots
Air Temp: 26.7°C, 80.9 °F
Bar. Pressure: 1012.6 mbar
Humidity: 75.6%
Sea surface temp: 27.0°C; 80.1 °F
Visibility: Unlimited