Earth Science: Geology, the Environment, and the Universe

Chapter 16: The Marine Environment

Problem of the Week

The Final Frontier

Think About It

Organisms that live at great depths often have oddly shaped bodies and large eyes, perhaps to collect all the light possible, or no eyes at all. Many deep-sea organisms have large mouths with special adaptations for swallowing whatever sized organism comes along. Many deep-sea organisms use bioluminescence as a way to attract food and possibly mates.

Students should be able to infer from the conditions some of these adaptations and probably some of their own. You might even assign students to groups and have them design their own deep-sea organism with features designed especially for survival at great depths.

Problem:

To determine the pressure at 35,800 feet (10,740 meters):

  1. 35,800 / 33 = number of atmospheres of pressure
    = Approximately 1085 atmospheres

  2. (number of atmospheres × 14.7 psi) + 14.7 psi = total pressure from the atmosphere and the water.
    (1085 × 14.7 psi) + 14.7 psi = 15,964.2 psi

Try to impress upon the students that this is a "fantastic" amount of pressure per each square inch of human, machine, or organism. You might go back to the previous problem where they calculated the total pressure on the surface area of the average human and do that again with this value.

When sending a machine to these depths, the structure of the vessel, combined with internal pressure of the gases in the vessel keep the vessel from imploding. Deep-sea vessels often employ the "arch" in the design. Arches in buildings and in other designs, can distribute the weight or pressure to other parts of the structure, adding strength and support.

Organisms adapted to depths have bodies that are filled with fluids. These organisms have few gas spaces within their bodies, such as the lungs of a human. These features allow the organisms to be relatively uncompressible and less affected by the tremendous pressures. This is a simple explanation, for something that is not so simple.

Resources:

  1. Michael D. Lemonick (1995).
    The Last Frontier. TIME Magazine. Volume 146, No. 7.


  2. Ocean Planet


  3. The Physics of Underwater Diving

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