Transcript
STEPHEN PALUMBI: We went there to basically witness what happens when you do the most destructive thing we've ever done to the oceans, which in this case is dropping 23 atomic bombs on a coral reef. The question is: then what?
JAMIE TAHANA: Then what?
SP: [laughs] then what, for example, is that there was an island there in 1935 and now it's 160 feet of water because it's a hydrogen bomb crater and in that hydrogen bomb crater marine life is trying to come back. Bits of coral growing up from tiny pebbles to the soccer ball size to the size of small cars, and fish swirling around sharks. The ocean tries to recover, even from something as devastating as these bombs.
JT: And it's been more than 60 years since the bombs were dropped. When did this life start to re-emerge?
SP: We know that there were corals that were recovered from pretty deep - 120 feet or so - that were continuously growing some places in the lagoon and we found a very big coral colony, like the size of a pool table, and we figured that they must have taken 40 years, 50 years to grow that big meaning that they started growing again just a decade or so after the bombs. So I think things started coming back pretty quickly, but it's still hit-and-miss -- if you don't mind the pun -- and it's a very strange environment.
JT: Strange in what way?
SP: Well the diversity of things that is there and is not there. Strange in that the bottom of this hydrogen bomb crater, for example, is like talcum powder - so, so fine. There are cracks in the reef that go for hundreds of yards straight where this one side of the reef has bumped up a couple of feet from the other. And yet, we found a large number of corals and a good coral diversity growing to the point where we started wondering, well how are these animals that have lived there - and corals are animals - how have they lived there for 40 or 50 years in the presence of this underlying radiation and still done so well?
JT: The area is bathed in radiation still, isn't it?
SP: Well, you know, it's got a higher radiation level than it should. There are places on the island where we register three, four times background radiation and, you know for example, the coconuts there - they planted a lot of coconuts after the blast but the coconuts are radioactive, you can't really eat them or drink the milk or anything like that because they are pulling caesium-137 out of the ground water that's still in there and still pulling it up onto the surface. So it's impossible to farm there, you can't really fish there, you can't drink the ground water. You can breathe the air though, so everything's good, right? [laughs]. So it's a very, very devastated place from the standpoint of the original human population and the longest-living organisms there are animals that have had to deal with this radiation for so long. Coconut crabs, for example, they eat nothing but radioactive coconuts on Bikini Atoll and how they're dealing with the caesium-137 we just have no idea.
JT: Yeah so are these coconut crabs or the corals you've seen, do they differ from what you'd see in less radioactive water?
SP: Not noticeably that you can see. And that was one of the strangest things, you see these very big corals in Bikini Atoll, they've been growing for 30 or 40 years in this higher radiation source and the kind of work that we do here in the lab has a lot to do with the genetics of corals. We have long been fascinated by how corals can live so long, I mean these corals that we're talking about are 40 or 50 years old, but we know that other corals similar to them are 500 years old or 1,000 years old. What we were trying to do is bring a different level of technology in and say, well, can we then use genome sequencing to figure out exactly how much damage the radiation in the environment has been doing.
JT: Genome sequencing being?
SP: Genome sequencing being you take all of the DNA that is an organism. The stuff that basically makes up our cells and lets them work. That stuff is made up of a whole string of chemicals called bases and then the sequence there of those bases is essentially the sequence of the entire genome.
JT: Are you starting to see anything that would suggest that they're genetically different yet, though?
SP: You know, I think what we're seeing is that the corals themselves have a mechanism within them to just keep their DNA in very, very good shape. Because if they can't, then there's no way that they can grow to be the size of a house and 1,500 years old. So that's the intriguing thing for me, just the basic way corals can live with these very long lifespans and these enormous sizes must mean that they have a way of making sure their DNA, their genetic information is protected. As a difference, humans after 50, 60, 70, 80, 90 years, we begin to get mutations that cause us to have cancers. There's no known cancer in coral.
JT: So this research into the corals, and how their DNA may be able to weather such radiation. Because as you say, human genes mutate after a few decades and develop cancers and such, much more so if you're exposed to radiation.
SP: Right.
JT: So this has implications for human health, possibly, doesn't it?
SP: I think it does, possibly. It falls into that category of basic research which is, you know, what if this whole thing opens up a new area of research. Suppose corals, in fact, have a whole set of abilities to maintain the integrity and perfection of their DNA sequence. Suppose they have a whole set of abilities that we don't have in our own bodies and that we would never know about unless we saw them in action. And that's what we're hoping to do: catch these abilities in action in corals, particularly by looking at the Bikini island ones, because maybe it will give us a whole new set of ideas about how, you know, DNA can be protected and then kept in the highest fidelity that we would ever want to. It's the kind of high risk but high gain and down the line kind of possibility.
