Dr. John R. Delaney, the father and leader of this expedition, is a professor
in the School of Oceanography, University of Washington. He spoke to NOVA about
his hopes and fears for his brainchild as well as about the bigger picture: Why
study these chimneys? What can they tell us about how life started on Earth,
and how it may exist on other planets?
NOVA: Is this a risky endeavor?
Delaney: There's always a risk, I think, when you're trying to do something no
one's done before. There's not a book we can go to to get the answer, there's
no one we can call up and say, "How strong are these things, how easy is it to
detach it from the seafloor?" There are no answers. We're going to develop
those answers ourselves as we go.
On the other side of the coin, though, I'll say there's risk in not doing
something like this. The risk is clear. There are a lot of things we wouldn't
understand if we didn't try to do something new and different. So there's risk
both ways, and I would far rather try and not succeed fully than to have the
idea and just not pursue it.
NOVA: What was it like seeing your first black smoker chimney?
Delaney: The first time I ever saw one of these large sulfide structures was in
1984, and it was absolutely awe-inspiring. It was not just a straightforward
chimney-shaped object with billowing black smoke coming out the top. It was
draped with a hanging-garden type arrangement of lush animal growth in the form
of tubeworms and limpets and snails. It was a stunning experience, and I've
never forgotten it. It's as vivid today as it was 14 years ago.
NOVA: Why study hydrothermal vent systems?
Delaney: Submarine hydrothermal volcanoes constitute a very primitive form of
system. It is probably one of the most common systems that existed on the
planet throughout much of its early evolution. There were few continents in the
early Earth, there were few warm, shallow ponds, as Darwin would suggest life
began in. But there were submarine volcanoes and there was an ocean. So
understanding the very basic building blocks of life and the mechanisms by
which those building blocks come together can be attacked by looking at
submarine hydrothermal systems in a comprehensive way.
NOVA: Why bring up a black smoker?
Delaney: There's a great deal that we can learn by simply going to the seafloor, picking
up small samples, and bringing them back; there's a great deal we can learn
from visiting once a year, maybe once every two years. But to truly understand
the system, you must observe how it functions. It would be the equivalent of
trying to understand the human body without ever being able to look inside. You
couldn't really observe a human and say, "Well, I know how that organism
works." They wire astronauts when they put them in outer space, because they
want to keep track of how they're functioning. We need to wire the seafloor in
order to understand how it functions.
NOVA: What will happen when you remove an active black smoker from its site?
Delaney: In a sense, this is a controlled experiment, in that when we detach
the sulfide structure from the seafloor, we may change the way the entire
submarine hydrothermal system behaves. Or we may not. It would be the moral
equivalent of removing one of the flutes from a large church organ and hearing
everything else go out of tune, because you've plucked the flute. If that
happens, we'll get major new insight into the geometry of the fluid flow below
the seafloor, which is very difficult to do.
NOVA: If you succeed in bringing it to the surface, what will you do with it
Delaney: We plan to dissect it. If we're to understand how submarine volcanoes
can support life without sunlight, we have to dissect those systems and analyze
them as thoroughly as possible, and compare that with information we have about
how they behave. How does the fluid flow through the pores? How does it deliver
nutrients to the system? Those are the things we're trying to understand.
In fact, the insights we'll gain by dissecting the entire structure after
having documented it thoroughly in place is one of the most exciting aspects of
this whole program for me. Those two keys—thorough documentation in place
and thorough dissection—are the heart and soul of this program. We will pore
over this thing like no sulfide structure from the seafloor has ever been
examined before. This will be the most thoroughly dissected and analyzed piece
of rock since they brought back moon rocks.
NOVA: Will you do before-and-after studies of the black smokers you're going
Delaney: To truly make the most of this experiment, we need to be able to make
real-time measurements on the seafloor before, during and after the recovery,
so that we can see what the effects are. We want to know boundary conditions on
what the environment was like prior to recovery. We want to know what the
effects are when we actually snap the structure off the seafloor. And we'd like
to know how it recovers.
NOVA: Could life on Earth have gotten its start in hydrothermal vents, and how
will we ever know?
Delaney: Ten years ago people laughed when you suggested that life may have
originated in submarine hydrothermal systems. They're not laughing anymore.
It's still controversial. There's a lot to learn, a lot to be proven. And it's
going to be very difficult to truly examine what the origin of life might have
been. I don't honestly believe that what we're doing will illuminate that
particular issue in a definitive way, partly because it happened about 3.5
billion years ago, and it's a difficult experiment to rerun once life has been
spawned on a planet.
But to understand the dynamics of the system in which it might have happened is
a step in the direction of refining, developing, and throwing out models that
either work or don't work. And that's really what science is about—coming up
with hypotheses, testing the hypotheses, and dropping like a hot potato the
ones that don't make sense or can't fit the data.
NOVA: What does the study of hydrothermal vents and their associated life
suggest about the possibility of life on other planets?
Delaney: The discovery that life can be supported by volcanic activity in the
presence of liquid water without sunlight is a profound new insight—new
meaning one or two decades. Also the discovery from some of the NASA programs
that volcanoes are common in the solar system. The combination of those two
insights is a powerful guideline for the search for life on other planets.
Recent evidence from the Galileo flight has shown quite clearly that liquid
water exists in the subsurface of Jupiter's moon Europa. In my opinion there is
also evidence in those images for the presence of volcanic activity below the
ice. And so the presence of liquid water and submarine volcanoes, one could
argue, is a blueprint for how life may be existing elsewhere.
The search for life beyond Earth has been going on for a long time, but I would
remind you that exo-biology is the one business for which they have nothing yet
to study. The closest that they will come to having something to study for a
few years anyway will be, in my opinion, the systems that exist on the
seafloor. One of my great dreams, in fact, is that our understanding of the
submarine systems here on Earth will guide us unerringly to the discovery of