Expedition Explores the Arctic Sea Floor A team of scientists is heading toward the Gakkel Ridge in the Arctic Ocean, hunting for hydrothermal vents on the Arctic sea floor. On a six-week voyage, the researchers will use two new autonomous undersea vehicles to try to explore the world under the Arctic ice.
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Expedition Explores the Arctic Sea Floor

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Expedition Explores the Arctic Sea Floor

Expedition Explores the Arctic Sea Floor

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No one has ever laid eyes on the bottom of the Arctic Ocean - is how the Woods Hole Oceanographic Institution begins to describe the reason that for the first time in history, robotic explorers will be sent deep below the Arctic ice. The underwater vehicles will be on the hunt for hydrothermal vents, think of them as sort of underwater geysers, super hot water spewing out of cracks in the ocean floor. And at those vents, we usually find strange life forms that survive in this hotter than boiling water, in conditions that seem too harsh to support life, no sunlight, you got a chemical brew that could kill less hearty creatures. Scientists think the organisms living at these vents may hold clues to what life might have been like on the early Earth in similar inhospitable conditions.

Onboard the Swedish icebreaker, Oden, in the eastern Arctic Ocean, members of the research team - the chief scientist and the lead biologist - join us by satellite phone to talk about the challenges of getting under the ice, what they're finding so far in their search for hydrothermal vents, and about the robots themselves - they're really unique, built by the Oceanographic Institution. We'll talk about it.

And if you'd like to join us, the number is 1-800-989-8255, 1-800-989-TALK.

Let me introduce my guests. Rob Reves-Sohn is the chief scientist for the Arctic Seafloor Expedition 2007 and an associate scientist in the geology and geophysics department at Woods Hole. And he joins us today from the research of Oden in the Arctic Ocean. Welcome to the program.

Dr. ROB REVES-SOHN (Chief Scientist, Arctic Seafloor Expedition 2007; Associate scientist, Geology and Geophysics Department, Woods Hole Oceanographic Institution): Thank you very much.

FLATOW: Thank you for being with us. Tim Shank is the lead biologist for the Arctic Seafloor Expedition, and he is an associate scientist at the biology department at Woods Hole. He is also talking to us from the Oden. Welcome to the program, Dr. Shank.

Dr. TIM SHANK (Lead biologist, Arctic Seafloor Expedition 2007; Associate scientist, Biology Department, Woods Hole Oceanographic Institution): Thank you. It's good to be here.

FLATOW: You're welcome. And joining us from Woods Hole is Jeffrey Seewald. He's an associate scientist in the department of marine chemistry and geochemistry at Woods Hole. Welcome to the program, Dr. Seewald.

Dr. JEFFREY SEEWALD: (Associate scientist, Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution): Good afternoon.

FLATOW: Dr. Reves-Sohn, how is it going in your search for these hydrothermal vents?

Dr. REVES-SOHN: Well, we're really just getting started. We've been on our station here at 85 degrees north for about two days, and we started our search by - we raised and lowered the sensors on a long wire down to the bottom of the seafloor and back up again, and we're looking for signals in the water column of the sort of cloudy and hot water that's discharged by those vents. So far, we've (unintelligible) made about nine casts, and we found evidence for hydrothermal plume on two of those nine casts.

FLATOW: And then is the plan to send down these robotic devices to explore them?

Dr. REVES-SOHN: That's correct. Once we feel like we have a reasonable idea where the vent fields might be on the seafloor, we deploy the robots and let them do the rest of the hard work for us.

FLATOW: Give us an idea of what it looks like in the surrounding area. If we were to be on your ship, what would be looking at?

Dr. REVES-SOHN: Well, it's white, very white. We're in the middle of the Arctic icepack, and there is very little open water here, the average is probably 95 percent or more. And the Oden is able to break its way through this ice, and we have maps with us that were made by an earlier expedition, the AMORE Expedition in 2001, and we used those maps to guide our surveys, but pretty much, it's white ice as far as you can see, and a gray sky.

FLATOW: Dr. Seewald, you've got a study planned for the mid-Atlantic Ridge. It goes down the middle of the Atlantic Ocean. How similar is that to the Gakkel Ridge where you are now?

Dr. SEEWALD: Well, the mid-Atlantic Ridge is a slightly faster-spreading oceanic ridge, and the Gakkel Ridge, on the other hand, represents an end member of extremely slow-spreading mid-ocean ridges. And so, the interest in this environment is that the processes may be slightly different and may constrain a further end member on what we might see. There are similarities in that the composition of the crust in the two environments are very similar, but the style of circulation may be quite different.

FLATOW: Mm-hmm. Tim Shank, if there are hydrothermal vents in many other places on the planet, why go to all the trouble to find them under the Arctic Ocean? What's significant, biologically speaking, about this Gakkel Ridge there?

Dr. SHANK: Well, 58 million years ago, when seafloor spreading started in the Arctic, the basin was largely isolated. And so, whatever animals may have (unintelligible) in these early times of hydrothermal venting in the Arctic that may have evolved in isolation. So as an evolutionary biologist, I really want to know what isolation means to the evolution of species.

We've gone around the world finding over 600 species in the last 30 years, and we've seen tie-ins into their distribution. So like you might find marsupials in Australia or something else in Mongolia, you find the same thing in hydrothermal vents. The Mid-Atlantic Ridge fauna that live there (audio gap) on what see off Mexico, for example. So they could be completely different here, up in the Arctic, and that's what we actually expect.

FLATOW: What's different about, Dr. Reves-Sohn, what's different about working in this icy condition? Is it much more dangerous? Is that the reason why you're using these robotics instead of the human submersibles?

Dr. REVES-SOHN: That's absolutely right. In the open ocean, we would send either a man submersible or what we call a remotely operated vehicle, which is a very expensive piece of equipment on a wire, down to the bottom of the seafloor to do the exploration.

But because we have almost complete ice coverage up here, it's not safe to send human beings under the ice, at least in our estimation, and it's too risky to send a $10 or $20 million (audio gap) under the ice because the ice is constantly moving and shifting, and there's a significant chance that you could snap the wire that the vehicle is on.

And that is why we've designed these robots because they're able to dive through the ice and flip (audio gap) and with no connection back to the ship, which (audio gap) something on the order of half a million dollars each, which is not cheap, but much cheaper than a remotely operated vehicle. So the eventuality that we very much hope (audio gap) is not the end of the world.

FLATOW: Mm-hmm. So these basically swim out on their own. They have - there's no tether on them and then they find their way back.

Dr. REVES-SOHN: Yeah, you were dropping out a bit. You asked if they can find their way back to the ship?


Dr. REVES-SOHN: So we use some acoustic systems in the same way that, you know, you have a computer modem, and some of us are still on that situation where we have to have a dial-up modem in our house. In that same way, the robots have a modem, and it communicates to the ship, the acoustic signals, and we're able to open up a little hole in the ice with the icebreaker, and then we use the modem to tell the robot where that hole is so that it can safely return to the vessel.

FLATOW: Mm-hmm. Jeff Seewald, once they find a hydrothermal vent, it looks like they've got a couple of possibilities, how do you study them? Do you catch the water coming out, and scoop it up and sample it and bring it back?

Dr. SEEWALD: In an ideal situation, that would happen, but the technology doesn't exist to actually do that right now. But what they will be doing is collecting samples of the biology, samples of rocks and samples of vent fluids that have mixed with seawater in the water column. And those types of samples can give an enormous amount of information as to what's happening in the subsurface beneath the ridge crest. And so, there's a lot of information to be had in terms of the composition of the fluids and the style of circulation from collecting these samples.

FLATOW: Mm-hmm. I'll ask anybody who might want to answer this. We keep hearing more and more now that, given the summertime in the Arctic Ocean, that the ocean, due to global warming, is becoming more and more ice-free. Would that make it easier for scientists in the future to, you know, to send robotics down there?

Dr. REVES-SOHN: It would. If it - it's hard, right now, we're in the middle of the ice pack. And there's ice everywhere as far as we can see. So any effect like that certainly hasn't reached to 85 degrees north. But in principle, sure, if the ice were to melt away, that would make our lives easier. If I could just go one step further, a lot of us, our job would be easier if we could drain the ocean. So, I think there's a lot of things we wish could happen. But who knows what will happen?

FLATOW: Well, that would be a one-time job, if you were draining the ocean, I'd say.

(Soundbite of laughter)

FLATOW: How long is the research going to be there? How long is this study going to take?

Dr. SHANKS: Well, we've been out for about a week now. We've had a total of 40 days with the icebreaker Oden. And we hope to cover this site we're sitting over right now, as well as another site. That's about a six-day or seven-day staying from here. The error we can't predict very well over this ice. It's easy to get locked up in the ice and not to break free. It can take twice as long as that.

But what's interesting is on the site that we're sitting over is actually one that's what we call them peridotite. It's actually mantle rock that's exposed to the seawater. It may not exactly have the volcanism we think of the other places that are associated with hydrothermal vents, but what we do find is a different kind of chemistry that comes from that mantle rock exposed to seawater. And when we have that different chemistry, we get different animals. And that's another reason why we've stooped here at this location on our way further up the Gakkel Ridge later on in the cruise.

FLATOW: So you really don't know what you're going to see when you see something?

Dr. REVES-SOHN: That's true. We have no idea what we're going to find.

FLATOW: That makes it even more exciting, doesn't that?

Dr. REVES-SOHN: Exciting and stressful, yes.

FLATOW: All right. Well, we'll let you go. And we've taken up enough time from your work. So I want to thank you for - gentlemen. And wish you all the best of luck. And hopefully, you'll come back, and we will find out later on what your results are. So, good luck to you, and we'll check in with you later. Thank you, very much.

Dr. SHANKS: Thank you.

Dr. REVES-SOHN: Okay. Thank you.

FLATOW: You're welcome. Rob Reves-Sohn is chief scientist for the Arctic Seafloor Expedition 2007, associate scientist in the geology and geophysics department at Woods Hole, at Woods Hole Oceanographic Institution in Woods Hole, Massachusetts.

Tim Shanks is the lead biologist for the Arctic Seafloor Expedition and associate scientist in the biology department at Woods Hole at Woods Hole, Massachusetts.

Dr. Seewald, we're going to have you stay with us.

Dr. SEEWALD: Sure.

FLATOW: So, if you'll hang on, we have to go to a break. And we'll come back and talk lots more about the Arctic. We're going to switch gears a little bit, and talk about other stuff. So stay with us. We'll be right back after this break.

(Soundbite of music)


FLATOW: You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.

We're talking this hour about the Woods Hole Oceanographic Institute's Arctic Seafloor Expedition. We were just talking with scientists aboard a research ship that's sort of in the ice out there in the Arctic regions trying to - we've sort of lost, we were losing satellite communications with them. We're trying to get them back now.

But we still have on with us Jeffrey Seewald, who's associate scientist of the department of marine - chemistry and geochemistry at Woods Hole. Our number, 1800-989-8255. Dr. Seewald, do you wish you were out there with them?

Dr. SEEWALD: I do. It sounds like a very exciting time. It's always a great experience when you can get that sort of technology together with the scientific objectives to actually try and study these systems.

FLATOW: Mm-hmm. And what was interesting is that we were getting into this a little bit with the scientists on board the ship, talking about, geologically speaking, they found that site to be very interesting. Why is that?

Dr. SEEWALD: Well, this is a region of the mid-ocean ridge system where oceanic spreading is occurring very, very slowly. And so the mid-ocean ridge is basically a 40,000-mile-long mountain chain where new crust is created in what is geologically very rapid time.

But the initial idea was that in very slow spreading ridges, there wouldn't be sufficient heat to generate hydrothermal systems. And this has actually turned out to be very wrong. And the earlier cruises to this region showed a very high abundance of hydrothermal plumes, which is indicative that there is actually a lot of activity in this particular environment.

FLATOW: And these are places, describe if you would for us geologically, where the ocean is actually spreading out and new ocean is coming up out of from underneath?

Dr. SEEWALD: Well, in extremely slow spreading centers, the formation of crust can occur by exhumation of pieces of the mantle, basically. And these are what, I think, Rob referred to as - or actually, it was Tim referred to as peridotites.

FLATOW: Mm-hmm.

Dr. SEEWALD: And these have a very unique composition, or not unique, but very different composition to other areas of the ocean crust where spreading is faster. And so, in faster spreading areas, the rock composition is what we call a basalt, which is very different and produces - when you react seawater with these rocks, produces a fluid of very different composition.

FLATOW: So it's interesting to go to theses different places and find different circumstances?

Dr. SEEWALD: Yes. And the big issue here is, or one of the big issues, is the different chemistry that results when you take cold alkaline seawater that contains oxygen and you react it with rocks in these environments at very high temperatures, and the chemistry changes completely. It becomes a very acidic fluid. It becomes - the oxygen is consumed. There's a lot of hydrogen sulfite. And all these - the change in chemistry is what supports the microbial and biological communities that live in these environments. So a change in chemistry can have an enormous impact on the biology that inhabits these areas.

FLATOW: And how different from - let me put it this way, how far around the nation do you have to go to find different places that have these different kinds of chemistries?

Dr. SEEWALD: Well, in the Pacific, for example, the spreading rate, the southeast Pacific, the spreading rate is significantly faster. The mid-Atlantic ridge is slow, what's considered to be a slow-spreading center, it's a little bit faster than the Gakkel Ridge. The mid-ocean ridge system basically is, you know, 40,000 miles long, this mountain chain. And so, it's basically in - everywhere in the ocean's basins where a new crust is being formed. So there are common features of the ocean basins.

FLATOW: Mm-hmm. Now, we know the National Science Foundation, the NSF, supports most ocean and polar research. But why was NASA - NASA, the space agency -interested in supporting this project?

Dr. SEEWALD: Well, NASA has an interest in looking for the possibility of life on other planetary bodies, and Europa, one of the moons of Jupiter being one environment. And so Europa is a moon that is covered with ice and may have the ideas that there maybe hydrothermal activity beneath the ice in this environment.

FLATOW: Mm-hmm.

Dr. SEEWALD: So, NASA, the - an obvious thing to do is to see if we can perhaps find hydrothermal vents and sample them beneath the ice on Earth, which would be considerably easier as a first step than trying to do that on Europa.

FLATOW: Mm-hmm. 1-800-989-8255 is our number.

There are two robots, one is called Puma and one is called Jaguar. That - were designed by Woods Hole itself?

Dr. SEEWALD: It is my understanding that Hanu Singh designed those vehicles, although I'm not absolutely sure about that. But it is - I think they were designed at Woods Hole.

FLATOW: Because you don't think of Woods Hole as being in the robot business. You'd think of them as being in the undersea exploration business.

Dr. SEEWALD: Well, we have actually a large engineering department here that actually has a long history of building autonomous vehicles and robotic vehicles for undersea research. So there is the - Jason is a well known vehicle…

FLATOW: Right.

Dr. SEEWALD: …which is a little different than these autonomous vehicles. There's been others, ABE was one of the first types of these robotic autonomous untethered vehicles.

FLATOW: How long in the planning is something like this? And the reason I ask it is because we've talked about global warming and the ice-free oceans. And we're hearing from the ship there that they're almost locked in the ice. It's ice all around the place. If they had known - if we had known that there, you know, there were going to be, if you wait a little longer in the season that the ocean might be a little bit more opened up because of global warming, and we haven't known this except for the last few years, might you have waited a little later in the season to do this?

Dr. SEEWALD: That certainly would make this project much easier. Sampling without the ice is something - we have a long history of sampling vents using the submersible Alvin and tethered vehicles. A lot of this project is - there's been a significant amount of technology developed with the autonomous vehicles. So I think it's still, from an engineering perspective, it's still quite challenging. But certainly, the - a lack of ice would make conducting this research much simpler.

FLATOW: Let's go to the phones. Bob(ph) in Jackson. Hi, welcome to SCIENCE FRIDAY.

BOB (Caller): Well, thank you, Ira. My question, very briefly. An old high school friend, who's a doctor in Florida, was responsible for some marine life so deep that they didn't have eyesight and they didn't have oxygen. They used those plumes, and they were actually a different form of life on Earth because they took in that sulfur from the plumes. And I'm wondering does that have any connection with what some of these findings are up in the Arctic?

Dr. SEEWALD: Yes. Those are exactly the types of organisms that Tim Shank is interested and other biologists are interested in studying.

BOB: Oh, really? Oh, cool.

Dr. SEEWALD: Yeah. When you - when you're - the reason that this life has no, didn't have any eyes was because, in the bottom of the ocean, there's no light, so there's really nothing to see.

But what's drawn a lot of interest in these hydrothermal vent systems is the fact that these biological communities are living off of the chemical energy that is created when you react seawater with the ocean crust. And these communities are living completely in the absence of photosynthetic activity. And so, it's referred to as chemosynthesis, where they garner all their energy from the chemicals that are venting at these locations.

FLATOW: Mm-hmm. And there's some theory…

BOB: A follow-up question, if I may?

FLATOW: Go ahead.

BOB: Does that mean that on other planets, without oxygen, there could be life?

Dr. SEEWALD: Yes. That - and that gets back to this question of NASA's interest. If the idea that life can exist on Earth in the absence of oxygen and living off hydrothermal vent chemistry suggests that if similar systems exist on other planetary bodies, that there may be the possibility of life elsewhere.

FLATOW: Thanks for calling, Bob.

BOB: Thank you, Professor.

FLATOW: Good question. And that's also the basis of thinking that, perhaps, life - that's where life stared on this planet; with the absence of light and…

Dr. SEEWALD: Yeah.

FLATOW: …harsh environments that were here in the early planet.

Dr. SEEWALD: Absolutely. You described these vent environments as being somewhat extreme earlier on in the show. But actually, for the microbes living there, it's quite comfortable. They have a constant supply of food. If they - on an early Earth, they would have been shielded from meteorite impacts, ultraviolet radiation. So it was a very nice environment in which life may have originated on an early Earth.

FLATOW: Let's go back to the phones. Let's go - it's Ike(ph) in Philadelphia. Hi. Welcome to SCIENCE FRIDAY. Huh? Try it again. Hi, are you there?

IKE (Caller): Yes. Hello.

FLATOW: Hi. Go ahead.

IKE: Hey. I'm trying to picture your scenario. You're on an icebreaker, basically, you're on a sheet of ice. How thick is that ice before we actually contact water so that you can send your probes down, for one? And two, are we looking for medicinal value in searching so far below the surface of the Earth?

Dr. SEEWALD: Yeah. I'm not actually on the ship. But my guess is the ice is several feet thick. And I think they - what they do is they - the icebreaker actually drives itself up on top of the ice and actually cracks the ice and creates an area behind the ship that is free of ice. So there's a trail, and that's where they put the instruments over the side.

And there has been - I'm not a biologist, but there has been, I think there is interest in the potential medicinal value of some of the organisms living on the seafloor, although I'm not particularly familiar with that aspect.

FLATOW: First you have to know what's down there, right? That's what's part of the expedition is all about.

Dr. SEEWALD: Right. That's right.

FLATOW: And it's surprising, I guess it's not surprising considering that the ice covers the water so much of the time, it used to be all the time that we've never explored this part of the ocean.

Dr. SEEWALD: Yeah.

FLATOW: But, it's also interesting that they're - we're now choosing, at this point in time, to explore it.

Dr. SEEWALD: Yeah. Getting back to this origin of life issue. One of the very interesting aspects of the Gakkel Ridge is that it is composed - there's a large amount of this rock type called peridotite. And that particular rock type creates these extremely reducing or hydrogen-rich environments when it reacts with seawater.

In addition, it contains minerals that are thought to be very catalytically active, so there's a lot of interest in this environment because of the potential to abiotically form organic compounds that would be necessary as precursors to life., simple molecules that could be organized into simple primitive organisms.

FLATOW: Do you have any idea how many other spots on Earth that are unexplored like this one?

Dr. SEEWALD: Well, we've, I don't know the exact numbers, but we've explored a very small region of the Earth's mid-ocean ridge system. So there are lots of regions that we don't really know about. And what's exciting about doing this kind of research is that every time we go to a new area, we always find something new that we - was unexpected and, scientifically, quite interesting.

FLATOW: Talking about deep explorations this hour on TALK OF THE NATION: SCIENCE FRIDAY from NPR News.

Talking with Jeff Seewald of the Woods Hole Oceanographic Institution.

Can people - can we follow this on the Web anyhow, you know, students, public?

Dr. SEEWALD: Yes. There are two Web sites that I am aware of. There's the Dive And Discover Web site. If you go to the Woods Hole Oceanographic Web site, which is www.whoi.edu, and then there's another Web site that you can link to from there called Polar Discovery, which I think is having a day-to-day log of the - what's going on on the ship.

FLATOW: So you can keep track of it. And it's just very early on in their exploration period. We heard from - onboard the boat that they think they just had a signal from a couple of spots.

Dr. SEEWALD: Yeah. This process of finding vents on the seafloor when you're doing it on open ocean is fairly time consuming. And it's not unusual to spend a week looking for vents on the seafloor before you or even - and longer. Doing this in the ice, where everything is happening, I imagine much slower than it would be in the open ocean. So it could be quite a while before they actually find something.

FLATOW: 1-0800 - I think we have time for one more call, 1-800-989-8255. Let's go to Philadelphia. Hi, welcome to SCIENCE FRIDAY.

Unidentified Man: Hi. I was wondering if perhaps he's able tell us what the chemistry of the peridotites are and if it's similar to the other ones that are all around the world?

Dr. SEEWALD: I'm not familiar with the particular chemistry of the peridotites on the Gakkel Ridge. I'm actually a water chemist. But the lack of silica in a peridotite in general, compared to a basaltic rock, which has a higher silica content, and a very high iron content that is present in peridotites allows them to create this very reducing environment when it reacts with seawater. Significantly, more reducing than you might find.

FLATOW: Reducing, meaning what?

Dr. SEEWALD: Reducing meaning high hydrogen, very low oxygen concentrations, and very high hydrogen concentrations, which - hydrogen is sort of a key ingredient for both maintaining life in these systems. And if abiotic or synthesis of organic compounds in the absence of life is going on, you need rather high hydrogen concentrations.

FLATOW: What would be the maximum outcome of this? What's the best you could expect from a mission like this one?

Dr. SEEWALD: Well, the best outcome would be that they find vents everywhere they go, and they don't lose any of their vehicles.

And the - from a biological perspective, I think there's a lot to be learned in terms of the biogeography of different species. So there's a possibility that there are organisms living in this environment that are totally unique because there's been no communication due to the restriction of water flow in this rather restricted basin. So it's an opportunity to look at evolution in an environment that may be totally independent from the rest of the world's oceans.

FLATOW: Because it is so isolated up there.

Dr. SEEWALD: Yeah.

FLATOW: Yeah. All right. I want to thank you for your taking time to be with us.

Dr. SEEWALD: Great to be here.

FLATOW: And good luck to you.

Dr. SEEWALD: Thank you.

FLATOW: Jeffrey Seewald, associate scientist in the department of marine chemistry and geochemistry at Woods Hole Oceanographic Institution.

Also, I want to thank the folks at Woods Hole, who were on the exploration ship for the satellite time they were able to give us today.

We're going to take a short break. And when we come back, we're going to just change gears a little bit. We're going to stay in the Arctic Region. But we're going to onshore to - there's another Arctic mystery. These guys are down there looking for these hydrothermal vents. Well, there's a sort of a global-warming-related Arctic mystery that's happening on land about the disappearance of some pools of water, some ponds that have been around for countless years, thousands of years, they're suddenly gone.

And one scientist has published a research about this and is wondering why and how, and possibly, signs of global warming. He'll be back to talk with us after the short break. Hope you'll stay with us. We'll be right back.

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