Half A Century Later, A Return To Challenger Deep

The film director James Cameron has just completed a dive to Challenger Deep, the deepest point on Earth at nearly 36,000 feet under the sea. His manned descent is the first in 52 years, since the oceanographers Don Walsh and Jacques Piccard explored the Mariana Trench in the bathyscaphe Trieste.

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IRA FLATOW, HOST:

This is SCIENCE FRIDAY. I'm Ira Flatow. What's to be found at the very, very bottom of the ocean, in the deepest recesses of the Mariana Trench right out there in the South Pacific? Earlier this week, director James Cameron, the man behind "Avatar" and "Titanic," he went down there, solo in a tiny sub. And here is what he saw. I'll tell you right now. He was down there, and he was able to come back. And when he came back, he told us all what was going on down there. He conducted a news conference and - we'll get to that in a minute, all right?

Before we get to that, let me introduce to you Captain Don Walsh because although Cameron was - went down there, he's just one of two living people to have visited the deepest gash in the Earth. The other man went 52 years ago in 1960 and has been an adviser and mentor to Cameron on his trip, and he's here with us today. Captain Don Walsh is an oceanographer, honorary president of the Explorers Club, president of International Maritime. He joins us by phone from Waikiki. Welcome to SCIENCE FRIDAY, Captain.

DON WALSH: Thank you, Ira. It's good to speak with you.

FLATOW: Tell us about that adventure. You went down there, what, 52 years ago in 1960.

WALSH: Yeah. It was Jan. 23rd, 1960. We had been operating the U.S. Navy bathyscaphe on test dives at Guam for about five months, each dive being progressively deeper to find out the moods and modes of the Trieste, a rather radical craft for its time. And at that time, there was like only two airplanes in the world or only two of these manned deep submersibles in the world. The French navy had one and our navy had one.

FLATOW: Yeah.

WALSH: And we culminated that dive series then in January of 1960 with a dive to 24,000 feet, and then about 10 days later, the dive to the deepest place in the world ocean.

FLATOW: Now what did you see when you got down there?

WALSH: Well, just before we landed, we spotted what we thought was a flatfish, a white flat - like a halibut or a sole, a foot long. And that was quite a sighting, if true, of a higher-order marine vertebrate in such - at such a great depth. And it was a bottom-dwelling type of fish, so it meant that it was where it belonged and that there was food down there and sufficient oxygen to support it. Now Jacques Piccard, who was my co-pilot and son of the inventor of the bathyscaphe, Professor Auguste Piccard, he and I were not ichthyologists. We were engineers. We were, if you would, test pilots of this vehicle trying to prove out its capability. So in the subsequent years, we've been advised by all kinds of scientists that we didn't see that.

FLATOW: Uh-huh.

WALSH: Yeah. After we landed, though, we stirred up the bottom sediment, which is very fine, very granular, and it remained in suspension for the full 20 minutes we were down there. It was like sitting in a bowl of milk. So we did not get any images on our dive. And that was - stirring up sediment was not unusual. Every dive, you do it when you land. But there's a subtle current that'll move that sediment away from the window, and you could make pictures. In this case, it did not happen. And so the first images ever made of the deepest place in the ocean were actually made 25 years later by a Japanese - sorry, 35 years later by a Japanese unmanned submersible called Kaiko or a Japanese word for trench.

FLATOW: Mm-hmm. Let's - I want to - I held playing back the clip because I wanted to hear you describe what you saw. Now, we have a little clip of James Cameron who just came back, and we have a clip about what he saw when he went down there.

(SOUNDBITE OF NEWS CONFERENCE)

JAMES CAMERON: When I came down, I landed, it was a very, very soft, almost featureless plain, and it just went out of sight as far as I could see. The Challenger Deep, which is only a small part of the Mariana Trench, is something like 50 times the size of the Grand Canyon. So, you know, this is a vast frontier down there that it's going to take us a while to understand.

FLATOW: Now, can you relate to what he saw? Are you - or were you in a different part of the trench?

WALSH: No, no. Absolutely, Ira. The actual Challenger Deep is - consists of really three deep places. But generically, they're called Challenger Deep and all of about equivalent depth over, say, an axis of about 30 miles. And yeah, what he said is quite correct. He had the advantage, though, that with modern technology, 50 years later - batteries and modern sensors and equipment - he could stay down there. So he could not only wait out the cloud of sediment, if you will, but he could move around. So he just waited out the initial cloud from landing and then was able to make direct observations, something we were unable to do.

FLATOW: Cameron is working with a team of scientists to solve some of the mysteries of the deep, and one of the researchers whose working with him is with us now, Doug Bartlett, chief scientist in the Deepsea Challenge. He's also professor of marine microbial genetics at the Scripps Institute of Oceanography at UC San Diego. He joins us by satellite phone from the middle of the Pacific. Welcome back to SCIENCE FRIDAY, Dr. Bartlett.

DOUG BARTLETT: Hi, Ira. It's great to be here. Hi, Don.

WALSH: Hi. Good - why don't you come home?

(SOUNDBITE OF LAUGHTER)

BARTLETT: Well, it's pretty nice out here. Here we are camped out in the Ulithi Atoll, which is within Yap State in the Federated States of Micronesia. It's a pretty beautiful place out here, and we're getting ready to steam out once again to the Challenger Deep.

FLATOW: And what are you - what is the purpose - what is the aim of doing this?

BARTLETT: Well, as Don, and as you heard Jim say, this is a large area. This is a significant portion of our biosphere, the deep sea in general, not atoll environments in particular so much. But these are places of extreme adaptation. They may be inverted islands of biodiversity, places down deep where distinct life forms exists, and we'd like to know a lot more about who's down there and what are they doing, how do they influence Earth's biogeochemical cycles, and what kinds of extreme adaptations do these life forms have. So at the biological level, those are some of the questions we'd like to address. And of course, there's the issue of why is this big gash down there in the Mariana Trench, in the Challenger Deep? What is the subduction process that accounts for that great trench?

FLATOW: You know, it's hard to believe that more people have walked on the moon than have actually been down to the deepest part of the ocean.

WALSH: That's correct. Twelve people have been on the moon and only three have been to the deepest place in the ocean.

FLATOW: And Doug, did you guys put a chicken down there in one of the trenches?

(SOUNDBITE OF LAUGHTER)

BARTLETT: We did - during some of the engineering work that was going on in the New Britain Trench, we did some experiments with bait. It's useful to attract organisms to landers or to the submersible. And we did some work with chickens. And we had a whole chicken in one trap when we deployed it. And when we recovered it, it was completely deboned. I mean, there was just no meat there at all. It was just bone. It was as if scarab beetles had gotten a hold of this chicken and gnawed it all the way to the bone. It was very impressive. What we had found were these large amphipods. Amphipods are crustaceans. They're sort of like shrimp and - amazing abilities to smell out food sources in the deep sea. And they had been attracted by the smell of the chicken and had devoured all of the meat. It was quite a sight.

FLATOW: Captain Walsh, you had an unusual event happen on your descent, did you not? Something unexpected occurred?

WALSH: Yeah, we had several. That was - unusual was usual, if I can mix the metaphor. Yeah, at about 30,000 feet we had a non-pressure boundary acrylic window crack. We didn't know what it was at the time. We had this huge bang. And you know, the outside pressure is 5 tons per square inch so that if there had been a failure of a pressure boundary - that is, our cabin - we would have been dead before we even knew it, if you will.

And we looked at all our gauges and such, and everything seem to be normal. We didn't know what the heck it was, but we just decided to go ahead and proceed with the dive. And then once we got on the sea floor, I was able to do an inspection at my leisure, if you will, and I discover the crack in this window. But it was not mission-limiting in the sense that it was a violation of pressure boundary. It may have affected our ability to get out of the cabin once we got back to the surface. As it turns out, we were able to get out and get topside while we were afloat on the surface.

FLATOW: Doug Bartlett, Jim Cameron was talking about almost describing the bottom of the ocean there as looking like so barren, like the surface of the moon, like in, I think in one interview he described it as it looked like being on another planet. Why are we not seeing the giant tube worms and stuff that we normally associate with deepwater places?

BARTLETT: This is an oligotrophic or low-nutrient deep-sea environment in the Challenger Deep. The New Britain Trench was much more productive, and so I think that accounts for some of the difference between the trenches. But with regard to hydrothermal vents and cold seeps, these are places where there's lots of energy and there's lots of biomass, and you have all these exotic and charismatic life forms, like tube worms and clams. Off of the trench, in the forearc of the Mariana, there are some amazing seeps and hydrothermal vents, and you can find liquid CO2 and liquid sulfur in some pretty exotic, extreme places.

But down at great depth in the Mariana Trench, where there are very few nutrients, along Jim's transect we saw amphipods. There were some of these smallish amphipod crustaceans, but not much beyond that. And I think it just relates to how little productivity exists in the overlying waters. There's not a whole lot of photosynthesis that's taking place in the shallow waters above the trench.

FLATOW: So are the living things down there just depending on what falls down that they can eat, like your dead chicken you set down there, waiting for stuff to come down and eat it, from above?

BARTLETT: I think that's true. I think they're largely dependent on the particulate organic matter that makes its way down deep. Now, some of the organisms, the microorganisms, are able to fix carbon, and they probably get energy from unusual sources. So, for example, during some mineralization processes, hydrogen can be produced, and some of the organisms down there are undoubtedly living off of hydrogen. And so at the microbial level there are diverse physiologies that may not be so dependent on the particulates. But overall, I would suggest that the ecosystem is dependent on particulate organic carbon, and things like chickens or whales or large carcasses coming down from above are manna from heaven.

FLATOW: Hmm. I'm Ira Flatow. This is SCIENCE FRIDAY from NPR, talking with Doug Bartlett from Scripps Institution of Oceanography and Captain Don Walsh, who's honorary president of the Explorers Club, president of International Maritime Incorporated. What - in the next dive, Captain Walsh, did you - well, in the first dive, did you advise Jim about how to take this dive and what to see and give him general advice?

WALSH: Well, he's most generous in saying that I had some advisory role. My advice just before he shut the lid - the hatch, that is - on his sub to go down, I said, Jim, today you move from being an adventurer to an explorer. Have fun. That was my advice. Have fun.

FLATOW: Doug, was it fun, Doug?

BARTLETT: Well, I think all of the dives that Jim has been involved with have been exhilarating to him, to the engineers and the other personnel here on the Mermaid Sapphire ship, the support ship for the submersible. It's just thrilling, absolutely thrilling to see what Jim has done. After every dive, there's an opportunity to review some of the high-definition filming associated with it, and some of the images are just stunning. With all of the LED lights and the high-definition cameras, 3-D cameras, macro and wide-angle lenses, the views are just simply amazing.

I think Jim's analogy to being on another planet when he went down to the Challenger Deep, I think when all of us have a chance to see this in an IMAX movie or see this at home in a documentary, we'll be amazed at the beauty of it all.

FLATOW: And we have a clip of it on our website at sciencefriday.com, about some of the stuff that has been seen. Yeah, we can't wait to see it because, as you say, there are two fascinating things about that area, about that earth and under the water, one is the life that's down there and one is how the heck did a rift in the Earth's crust open up to create this - what, it's 50 times the size of the Grand Canyon?

WALSH: That's correct.

FLATOW: That...

BARTLETT: That's right. You know, we have a geologist here, Ira, on the cruise, and she's written - Patty Fryer is her name, from University of Hawaii, and she's written about this big gash and why it exists. And I think what Patty would tell you in terms of why is the Challenger Deep so deep, is number one, when you look at the Earth's surface and the various crustal plates, oceanic and continental plates, the part of the Pacific plate near the Challenger Deep is the very oldest plate. And by being old, that makes it dense, and by being dense, that makes it more amenable to going down deep.

As one plate goes underneath another during the process of plate tectonics, the denser plate goes deep. And the denser it is, it'll go even deeper. Also, when one plate goes underneath another, sometimes it gets scraped and sediment gets built up at that interface between the two plates, and that decreases just how deep the trench is. And there's very little of that happening in this case. And then finally at the Challenger Deep, there seems to be a tear in the down-going plate, and that tear allows it to take a steeper angle, and it also influences the structure of the overriding plate.

And so for those three reasons - and it's probably more to it than that, but at least what I can gather from talking to Dr. Fryer, those three reasons account for much of why the Challenger Deep is so deep.

FLATOW: And it's - and, you know, we talk about going into outer space, but there's so much to learn about our own planet right here. It's amazing. I want to thank you both for taking time to be with us today. Doug Bartlett, chief scientist of the Deepsea Challenge, also a professor of marine microbiology and genetics at the Scripps in UC San Diego. Captain Don Walsh, oceanographer, honorary president of the Explorers Club and president of International Maritime. Thank you both. And good luck to you, and we wait to see those films come back, as they used to say. Stay healthy and report back when we're ready to have a look.

WALSH: Thanks, Ira.

FLATOW: You're welcome.

BARTLETT: Thank you.

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