Earth Science: Geology, the Environment, and the UniverseChapter 16:
The Marine EnvironmentProblem of the WeekThe Final Frontier Have you ever heard space referred to as the final frontier? How
about the last great unknown left for the explorer? Well there are
many scientists, like Sylvia Earle, a former chief scientist at
the National Oceanographic and Atmospheric Administration, who see
the oceans as the final frontier. In fact, Earle thinks, "there's
a perception that we have already explored the sea," but that "the
reality is, we know more about Mars than we know about the oceans".
This perception may be a result of a growing awareness of the fragile
nature of the oceans, but there is still a great deal to be discovered
and learned. | (50.0K) Bathysphere William Beebe NASA: Ocean Planet |
The conditions encountered during the exploration of
the abyssal depths of the oceans are as hazardous, and foreign to humans,
as are the conditions in space. There is no light, the temperatures are
frigid, and the pressures are intense. To travel there, humans must create
an artificial environment, just as we must do to travel in space. Only in
the deep ocean, it must be more than a suit. In 1951, the bathyscaph Trieste
took two men 35,800 feet (10,740 meters) down to the deepest spot in the
oceans - the Mariana Trench's Challenger Deep, southwest of Guam in the
western Pacific. Until 1995, there had been no return to those depths, and
even then it was via a remotely controlled submersible. So the depths remain
relatively unknown biologically, physically, and ecologically. Think About This: As mentioned earlier, the conditions deep in the ocean are inhospitable.
The lack of light, the intense cold, and extreme pressure are all factors
that inhibit exploration, and for the creatures of the deep, these factors
make for very interesting living conditions. If you were an organism living at these depths, what adaptations might
you need in order to survive? Brainstorm a bit about this question. Then
go check out these Web sites to see some of the organisms that live in
the abyssal depths of the oceans. The Problem: One of the greatest challenges the deep ocean presents to human explorers
is the extreme hydrostatic pressure at great depths. Hydrostatic pressure
is caused by the pressure of the water column, pressing down and in onto
an object. This is similar to atmospheric pressure studied several chapters
earlier. Going back to that chapter’s problem, we found out that there
were 14.7 pounds per square inch (psi) pressing down on an object at sea
level (or one atmosphere of pressure). This is the standard commonly used
by divers for measuring pressure, so it will be used in this problem instead
of an SI unit. In the ocean one additional atmosphere of pressure is experienced
for every 33 feet (9.9 meters) descended. At 33 feet below sea level,
the hydrostatic pressure would equal the air pressure at sea level + another
atmosphere of pressure (14.7 psi + 14.7 psi = 29.4 psi). *Check
this site to see how far down aided and unaided man and machine
can travel – - Suppose that you traveled in a deep sea submersible to the bottom
of the Mariana Trench. What would the hydrostatic pressure be at 35,800
feet (10,740 meters)?
- What type of structural and design features might your submersible
need to have to withstand the pressure at such depths?
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