Interview with Tim Shank : Part 2
by Lonny Lippsett, photo by Chris Linder

Tim Shank

WHOI biologist Tim Shank tests a light on the Camper vehicle, getting it prepared for missions to photograph and sample rocks and animal life around hydrothermal vents, if we find any.

What are some other interesting features of the Gakkel Ridge that might affect what life forms you find there?
There are some places on the mid-ocean ridge where material from below the Earth’s crust—from Earth’s mantle—has been lifted up and exposed on the seafloor. The Gakkel Ridge is one of these places.

Mantle rock has a different chemical composition from volcanic rock, or basalt, which we usually see on mid-ocean ridges. When mantle rock reacts with seawater, it produces different chemicals. These are the kinds of conditions that we think were present on the early Earth. So the microbes at Gakkel Ridge vents may be living relics of those that existed when Earth was young. That leads us think about the origin of life on this planet.

And also to life on other planetary bodies, true?
Yes—other planetary bodies that have similar types of environmental conditions. Jupiter’s moon, Europa, has an ice-covered ocean. And we know that Europa has some plate tectonic activity. The only requirements we see for life on this planet are plates moving about, releasing heat to an ocean and providing nutrients, such as hydrogen or methane. We know there are methane lakes on the moons of Jupiter. So the Gakkel Ridge may provide an analogous situation to what we might find on other planets.

What are your plans if you find vents on the Gakkel Ridge?
If we do locate vents, our plan is to make sure we get really good images of them, so we see how the animals are situated on the bottom, how they relate to the geology, to see the way they’re living on the seafloor. The next goal will be to collect and bring them back to the ship as intact as possible. We’re going to be sampling with a remote instrument that has jaws that are going to clamp down around these animals and try to rip ‘em up off the seafloor, and it’s not unlikely that we’ll get crushed shells, or tubeworms that are cut in half—if they are even tubeworms there. 

The next thing is look at their genes. I hope to bring animals back to the lab, extract and sequence their DNA—their genetic material—and compare it to other DNA we have from other vent animals around the world. We’d like to see, for example, if the Arctic vent animals are more closely related to Atlantic-type fauna or Pacific-type fauna. We can look at whether Arctic Ocean life might have migrated from the Atlantic or the Pacific. Or we might discover that their closest evolutionary relative is only in the fossil record. Or we might find something totally new.

What we can do with the DNA is reconstruct the past and see how these species have diverged from species that we know about today. And so we’ll put pieces of the global evolutionary puzzle together to get a sense of how life has evolved in vent systems.

What is your biggest hope about the expedition?
I hope the Arctic vent fauna are really different from anything we have seen before. I really want it to challenge our thinking.

What is your worst fear about the expedition?
 My worst fear is that we locate the vents, and we just get some fuzzy images of them, perhaps, and we go down there to sample them, and the sampler just breaks at the last minute, and we don’t get the samples back.

But, if we learn something from looking at the Gakkel Ridge and going under the ice, and apply it to other places on Earth, or other planets or moons, that’s also a real positive.

What do you like best about your job?
The experience I have finding life forms and learning how they came to be the way they are. That, to me, is almost a treasure and a miracle combined.

When I was growing up, I remember reading about Magellan and Vasco da Gama, and those guys, and I was disappointed because the age of exploration, the age of discovery, seemed over. They’d already found all the continents.

Well, the truth is there’s so much more on our Earth to discover, that it’ll never be done in my lifetime or ten more lifetimes. Less than two percent of our mid-ocean ridge system has been explored! We really have yet to see the diversity that’s out there, given how little we’ve looked. It’s going to be a thrill to get those animals on the Gakkel Ridge. If we do.



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