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Dive and Discover: Daily Updates

April 5, 2001
Rocks and Repairs


Sidelined with a broken thruster, ROV Jason returned to the ship after a night of scouting the black smoker chimneys we found yesterday. Sampling the rugged terrain around the chimneys requires maximum maneuverability with Jason.
 
The Deep Submergence Operations Group team worked since 4:30 this morning on the repairs so tonight Jason can again descend two and a half miles to continue hydrothermal vent exploration. Also heading to the bottom is the elevator, a platform loaded with 100 pounds of sampling equipment, water bottles, and blue coolers to stow animals.

Over the next few days, we will maneuver Jason to slurp shrimp, scoop mussels, and even catch crabs in fish-baited traps. Then the elevator will lift them to the surface.

Last night, we had a good look at the chimneys we are exploring, an area covering about half the size of a football field.

On the television monitors, five groups of black smoker chimneys were spotted swarming with thousands of busy shrimp, like bees on a hive. Four species of anemones, several snails, and an occasional crab passed before Jason’s cameras.

Using Jason’s temperature probe, the night watch found fluids with temperatures as high as 365°C (689°F) flowing from the hydrothermal chimneys. That’s hot—about twice as hot as the temperature you would set to bake bread.

Today geologists began dredging the slopes around the site to collect samples of the chimneys’ volcanic rock foundation. They dredge by dragging a large chain-link bag from the ship to scoop anything in its way. The rocks they collect help the scientists begin to paint a picture of the seafloor environment.

 “Imagine being in a spaceship and dropping a garbage can down to Earth. You drag it along and catch a window frame, a church steeple, and a desk. From that you have to determine what Earth is like,” said geochemist Susan Humphris.

April 6, 2001
Biological and Chemical Sampling at Chimney Site


When it came time to load water samples onto the elevator, Jason pilot Mark Bokenfohr had the difficult task of maneuvering Jason’s large metal claw to open one of the elevator’s bins. From the ship’s control van, Mark watched the monitor that showed the movements of Jason’s claw. For 20 minutes he struggled with a control stick to grasp a rope loop and lift the bin’s top. “It wasn’t this hard on the deck,” Mark said after successfully completing the job.

To understand the challenge of piloting Jason, put on a pair of ski gloves, jump in the bathtub and thread a needle under the water. It is possible, but it takes time, persistence, and lots of practice.

April 18, 2001
Minerals Form Before Our Eyes


Here in the Indian Ocean, when we watch the super-heated hydrothermal fluids gush from cracks in the seafloor and mix with the icy seawater, we are seeing the formation of new sulfide rock.

We learn from sulfides more about the origin of ores containing copper. Many ancient copper deposits now on land formed at the bottom of the ocean. “When we look at a hydrothermal vent, we are watching a mineral deposit forming before our eyes,” said Geochemist Susan Humphris. “This tells us a lot more about how they form than by studying mineral deposits on land that are millions of years old.”

Susan collects the sulfide rocks using ROV Jason. Once they are on board, Susan photographs, describes, and catalogs each rock. Some she cuts with a ceramic saw to share with microbiologist Anna-Louise Reysenbach (Portland State University). Anna-Louise grinds the rock and extracts microbial genetic material called DNA to determine what bacteria live on the chimney.
 
When the expedition ends, Susan will take over 250 pounds of sulfide rocks back to her lab for analysis with colleagues from Woods Hole and elsewhere.

April 20, 2001
New Hydrothermal Vent Field Discovered


Just before 2300 hours last night, ROV Jason climbed the steep, lower eastern wall of the Central Indian Ridge rift valley. Near 23°52’S, we saw on Jason’s remote video cameras the source of the hydrothermal plume that we mapped just a few days ago.

This new hydrothermal vent field is only the second active vent site identified in the Indian Ocean. Hundreds and thousands of husky Rimicaris shrimp crowd the black smoker chimneys as they forage. Delicate white anemones litter the vent bases. We see eel pouts, a type of ghostly-looking white fish, and yellow, orange, and white bacterial mats drape the site like floor rugs. We also had clear views today of gushing black smokers, white smokers and milder diffuse flows seeping out of ochre, yellow, and white vent mounds.

Tonight we celebrated the discovery with a cookout. Steward Mirth Miller, Cook Chris Poulin, and Mess Attendant Geryk Paige prepared a grilled feast that included ribs, fish, baked beans, and gooey brownies.

­—Amy Nevala




Originally published: March 1, 2002