Editor's Note: University of Southern California geobiologist Katrina Edwards is taking part in a three-week drilling project at the Atlantic's North Pond—a sediment-filled valley on the ocean floor—designed to locate and study what she calls the “intraterrestrials”: the myriad microbial life-forms living inside Earth's crust. This is her second blog post. To track her research ship's current position, click here. To see all her posts, see "60 Seconds in North Pond."
FORT-DE-FRANCE, MARTINIQUE (February 16, 2009)—Well, we've made it here. Unfortunately, the strikes, which followed us from Guadeloupe to Martinique, continue. But the good news is that we are told we will indeed launch tomorrow. I cannot wait! While we have been busy, busy, busy, I am getting anxious to get under steam.
I have my antinausea kit all packed: ginger, Bonine and wristbands. The Bonine isn't strong enough and I'm not entirely sure that the ginger and wristbands do anything at all, but I always bring them because the alternative, the patch, makes me into a crazy person.
The other good news is that our liquid nitrogen did arrive today, thanks to two escort cars that made it through the protesters. It was quite the brigade. So, while we are a little behind, we are really in pretty good shape and have high spirits about the coming weeks. Today was lots of planning and getting the equipment ready for coring into mud. Mud and more mud is what we will be getting.
A bit more information about what we'll be doing: The discovery that water is flowing underneath the bottom of the ocean is really a pretty new thing. We had figured out back in the 1970s that we had a little problem with the heat budget of the ocean. Imagine you and your neighbors both keep your thermostats parked at 68 degrees Fahrenheit [20 degrees Celsius] in the winter, but you notice that when you go to their house, it feels oh so much warmer than yours does. If you do what I might do, you'd go home and complain to your spouse that you had a problem with the insulation in your house—that your house was "leaky"—and probably costing you a fortune to heat.
We found the same thing on the ocean floor. The heat just didn't match up – the crust was cooler than we expected and it was known that there had to be leaks. Somewhere, water was getting in and out, and effectively acting like a radiator or a draft, taking the heat out of the crust.
A big part of that mystery was solved by the discovery of deep-sea hydrothermal vents at ocean floor spreading centers. Here, we can definitely see the "radiator" effect where you have hot fluids from below the ocean floor being spewed out at black and white smoker chimneys.
However, the discovery of hot vents didn't completely solve the problem. Scientists soon began to suspect that radiatorlike circulation of fluids in the subsurface, acting over much larger areas, may be as important in "cooling" the ocean crust as the hot vents. North Pond was one of the first places where we could actually see this—low temperature fluids very vigorously circulating far from hydrothermal vents, cooling the crust. This got hydrogeologists very excited, and they began to scheme concerning how to learn more about water flow through the crust. The idea that was hatched was to, in essence, plug the leak that was made by drilling at North Pond, and put some instruments in the hole so that they could watch what happened while and after the system came back to "normal."
This led to the start of an entire new mode of studying the ocean crust, and one that is really important for our planned study of the intraterrestrial microbes at North Pond. The means of plugging the drill hole uses a technology called "CORKs"—clever, huh? Which stands for Circulation Obviation Retrofit Kit. CORK says it all though.
Since North Pond was CORKed in the mid-1990s, 21 years after what is called Hole 395A was drilled, hydrogeologists have been monitoring fluid flow, temperature and pressures in the hole, and a lot has been learned about this "sub-seafloor ocean" that is flowing under North Pond.
What is funny for me to think about is that all this was happening when I was a little kid in the 1970s, and later through my college and graduate days. Some of the papers that have tied these 30 years of work together were published in the late 1990s, just a few years before I and a few others started hatching a plan for studying life in rock in the deep subsurface, and were looking for a place to do the work. The key people in this project—Wolfgang Bach and Geoff Wheat all have very young kids who will be grow up in parallel with the next phase of North Pond. Symmetry, somehow. And I'm fairly convinced we are not the last generation that will be fascinated by North Pond.
Enough with the historical stuff—onward to current and future research!
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Photo of Fort-de-France, Martinique, by Katrina Edwards, courtesy USC