VI. Black Smoker Chimneys
The
black smoker chimneys are the part of the vent system where thermal gradients
are the steepest. I want to look now at some of the temperature relationships.
The temperature of water coming out of black smoker chimneys has been measured
up to about 408 degrees celsius. That's right near the point where even
with that much pressure, the water tends not to stay in liquid form but
to go into a gaseous state. Now, what are these chimneys made of and why
should they be of interest to a biologist and not just to geologists? Geologically,
these chimneys are primarily metal sulfides. As the sulfide rich water comes
out, it's carrying not just sulfide, but also a lot of metals. In fact,
these black smoker chimneys have been mined for their copper for thousands
of years. These chimneys are interesting in terms of their geological history
because for centuries, people have been aware of these odd structures on
islands like Cyprus in the Mediterranean. Geologists really didn't have
an idea where these structures came from. They knew that the Mediterranean
Sea is a very seismically active area. As buckling has occurred, the black
smoker chimneys have been carried to the surface. As they come to the surface,
they bring up very rich sources of copper ore. So the black smoker chimneys
are of potential commercial value as a source of minerals. Biologically,
as you'll see in a few moments, there's also some interesting technological
spin off from these chimneys.
The rough texture of these chimneys is due in part to a lot of tubes that are
fabricated by annelid worms called Pompeii worms, a very appropriate name
for these organisms. These are the Pompeii worms, roughly four or five inches
long. They may be the most heat-tolerant of all marine animals.
How do we go about looking at the thermal relationships of vent organisms?
One of the points that I want to emphasize is that it's difficult to bring
up a deep sea organism in good shape. Someone asked earlier what fraction
of deep sea organisms can one bring up alive and maintain in a condition
that allows the animal to exhibit its normal in situ characteristics.
For the vent animals, that's a very tough challenge because a lot of the
organisms not only require high pressure, but also high sulfide. They also
may require a very precise temperature range. I should point out that Pompeii
worms from black smoker chimneys have never been brought up alive. They've
only been brought up freshly dead. I think one of the mistakes that we've
made in collecting specimens is that these animals may die of cold death
as we bring them up through the water column. So they're very tough animals
to work with. We have to use methodologies that allow us to work with either
freshly dead animals or specimens that are brought back frozen and then
assayed back in our home laboratories on land. What kind of experiments
can we do? Well, one of the things that one can do is to take tissues from
these animals and isolate certain materials that will give us an image of
how a physiological system is adapted to temperature and pressure.
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