Live From the Juan de Fuca Ridge

Wednesday, September 28, 2005

Dave Randle and Deborah Glickson

Daily Report

As forecast, the weather deteriorated overnight. By morning the winds were blowing at 25 knots and the white-capped seas swelled to over 15 feet. Since the weather was supposed to get worse, Jason Expedition Leader Phil Forte, made the decision to end the dive and bring the ROV to the surface. Safety is the number one priority, so the work at the bottom was put on hold once again and Jason and Medea were brought to the surface. The rough water made the recovery difficult and there were some tense moments as Jason swung on its crane. But the Jason crew skillfully managed to get the vehicle on deck without incident.

The long anticipated live High Definition broadcast was the main event of the day. Since Jason wasn’t in the water, the studio at the University of Washington had to rely on video collected earlier in the cruise. The beautiful images were the stars of the show as Co-Chief Scientists John Delaney and Deborah Kelley explained the work being done in this area along with scientists Peter Girguis, Dee Dee Meldrum, and Ginger Armbrust. The stormy weather reinforces the limits of this kind of expedition based science and the need for a permanent cabled observatory on the seafloor to bring continuous data year round to shore no matter what the conditions on the surface.

During the evening a science meeting was held to make plans for tomorrow’s broadcast and a lull in the winds allowed the recovery of ABE and an elevator. The elevator carried another Microbial Sulfide Incubator to the surface. A frenzy of activity in the Bio Lab ensued as the minerals that precipitated in the tube were methodically removed and preserved for analysis (see yesterday’s Daily Report).

Tomorrow’s weather could be worse than today’s. Winds up to 50 knots are forecast along with large rough seas. It’s a cliché, but the show must go on. So tune in tomorrow for another live broadcast from the Northeast Pacific.

Impressions

Deborah Glickson
As this cruise enters its final week, I’m struck by several things. The first is that at any given time, people are working. Working on instruments, data, J2, ABE, elevators, even personal impressions. This in itself is not too surprising, as we do our science 24 hours a day, rain or shine. Perhaps what I’ve really noticed is that people are helping with other’s projects. On any cruise, someone is always there to cheerfully lend a hand or a screwdriver, but this is different. Due to weather constraints and transfers, some scientists had to leave their instruments in the care of others, hoping for deployment before the cruise ends. So it’s become that Paul Tucker, on board to help with the drill sled, now has care of the remaining short-period seismometers. Mitch Elend, in charge of archiving video and imagery, will be lashing a homing beacon onto the remote access sampler (RAS) and making sure it is ready to go overboard. Both have been instrumental in working the high definition camera, too. Other people help simply be being available at the right time - Dave Randle and I got to unscrew some screws and take copious notes after the first sulfide microbial incubator was brought aboard two nights ago, which was tremendous fun! Others have spent hours and hours in the J2 control van covering shifts, making sure that no one gets exhausted during the late night dives.

I observe that the sense of cooperation is not just at the instrumentation level, either. Almost every day, I witness ABE and J2 crews collaborating on transponder surveys, troubleshooting mechanical problems, and figuring out how to get the best use out of both vehicles. In turn, the science party works together to coordinate several projects, each with its own set of objectives and goals. In a perfect world, all the priorities for each project - seismology, water sampling, the sulfide incubator, high def imagery, microbiology, and geologic mapping - would be accomplished. VISIONS ’05, like all research cruises, has been far from perfect. High winds and malfunctioning equipment have lessened dive time, and the principal investigators spend long, painful hours deciding which tasks can be completed, knowing that for every instrument deployed, another will be pushed to a later, more tenuous position in the cruise plan. During these decisions, they consult with the J2 and ship crew, deciding how to turn a paper dive plan into a watery ballet of elevators, floats, weights, vehicles, instruments.

In the largest sense, this teamwork extends to all of our projects at the Endeavour Segment. As an example, earthquake locations from the seismic array can be integrated with seafloor geology, chemical and temperature measurements within diffuse flow and black smokers, and growth of microbes inside the sulfide incubator. Maybe that’s how interdisciplinary science should best be described - a cooperative effort to fully investigate a question.

Daily Question

Hi REVEL teachers,
This is Joan Carlson from Laguna Hills High School in Laguna Hills, CA. I teach 3 classes of Biology and 2 classes of Introduction to Life Science. My students are 9th and 10th graders.
I am introducing the hydrothermal vent ecosystem this week as we start our ecology unit. In preparing the unit I was investigating the REVEL website. One aspect of “Linkages Between earthquakes and Microbial Productivity” in the science section of Vision 2005 puzzled me. How are earthquakes related to microbial productivity? What kind of correlations do scientists expect to find? The only correlation I can think of is that if there is more vent fluid present, more microbes can live.

Answer

Hi Joan,

Thanks for the great question. It’s tricky and the connection between earthquakes and microbes isn’t an obvious one.

Many things can cause earthquakes at the spreading center. Two of these causes are rock cracking as it's exposed to cooler water moving down through the seafloor and by magma moving up and creating dikes. In both cases nutrients for microbes are released.

Magma releases hydrogen, hydrogen sulfide, and carbon dioxide as it cools and depressurizes when it moves upward. All three of these chemicals can act as nutrients for both aerobic and anaerobic microbes. Earthquakes caused by cracking rocks can also open up new channels for these magmatic gasses to move up toward the seafloor. The rising magma also heats the surrounding environment creating hotter hydrothermal fluid that carries more nutrients. And you’re right about the fact that earthquakes can open up cracks that cause increased hydrothermal circulation that will feed more microbes.

Another less obvious way is through the release of hydrogen directly from the rocks. As rocks crack more seawater can reach greater depths in the seafloor. The iron in the rock reacts (is oxidized) with the seawater releasing hydrogen that can also nourish microorganisms. It’s interesting to note that the hydrogen from this reaction has a different isotopic signature than hydrogen released from magma, so scientists can tell where the gas is originating.