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Written by: James Wood
Written on: May 2nd, 2012
Tags: mechanical engineering, physics, transportation, space, marine, water
Thumbnail by: U.S. Naval Historical Center
About the Author
James Wood is an undergraduate at USC majoring in chemical engineering. He enjoys playing rugby, scuba diving, and exploring the great outdoors.
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Volume XIV Issue II > Uncovering the Secrets of the Mariana Trench
In March 2012, James Cameron became the third person in history to dive to the bottom of the Mariana Trench, the lowest point on earth. The conditions in the bottom of the ocean are very harsh due to intense hydrostatic pressures and a lack of light. Nevertheless, deep sea diving allows us to study the oceanic fault lines and unique ecosystems that exist in the deepest parts of the ocean. The Trieste was the first craft to travel to the deepest part of the ocean, and advances in technology allow modern crafts, such as Cameron’s Challenger Deep, to explore the sea trench like never before.

Introduction

Hundreds of people climb Mount Everest every year, and 27 astronauts have been to the moon, yet only 3 people have ever visited the lowest point on earth. This point, known as Challenger Deep, rests 36,070 feet below sea level at the bottom of the Mariana Trench in the western Pacific Ocean [1]. In March 2012, Avatar director James Cameron made history by making the first solo dive to the bottom of the trench and by using the second manned craft to ever reach the bottom. His vessel, Deepsea Challenger, took seven years to build and was designed specifically to reach the bottom of the Mariana Trench. Cameron’s purpose was not to set records but to document and analyze the conditions in the deepest parts of the ocean using modern technology. In recent years these marine trenches have come under increased scientific interest due to the presence of unique deep-sea life forms and the major role sea trenches play in the redistribution of the earth’s crust. Building dive craft that can travel to the sea floor and study these phenomena is no easy task though since the conditions that exist a mere 6.8 miles below the surface can crush all but the toughest of submersibles.

Why bother exploring the ocean floor?

Diving to the deepest part of the ocean might seem like a pointless achievement, but exploring the deep ocean floor is beneficial to society since it will help scientists to better understand the world we live in. Water covers more than 70% of the planet’s surface, yet to date we have explored only 5% of the space taken up by oceans [2]. In particular, deep-sea trenches interest many scientists in the fields of geology and marine biology. The movement of the earth’s tectonic plates forms peaks and valleys in the earth. Areas such as the Mariana Trench are formed when one plate slides beneath a second tectonic plate in a process known as subduction (see Fig. 1).
Earthquake Hazards Program/U.S. Geological Survey
Figure 1: The process of subduction involves the movement of one tectonic plate sliding beneath a second one.
Subduction zones are responsible for most of the active volcanoes on earth as well as most major earthquakes and tsunamis. In fact, 9 of the 10 largest earthquakes of the past century have occurred in subduction zones, as did the earthquake and tsunami that devastated Japan in March 2011 [3]. By exploring these fault lines and understanding how the plates interact with each other, geologists hope to better understand these natural disasters and more accurately model fault movement in subduction zones. The sea floor is also of great interest to biologists due to the unique life forms that live in the dark depths of the ocean. The average depth of the ocean floor is 12,200 feet, with sunlight penetrating only 1,000 feet below the waves [4]. Consequently, organisms living near the sea floor cannot use the sun as a source of energy and have developed unique alternatives to sustain themselves. For instance, while exploring geothermal vents in the earth, scientists discovered chemosynthetic bacteria that live off of the hydrogen sulfide exhausted from these deep-sea hydrothermal vents. These bacteria provide an energy source for other life forms and allow a unique ecosystem to thrive near these deep-ocean vents [5]. Scientists hope to analyze the DNA of these organisms and other sea creatures in order to understand how they function. Furthermore, since the sea floor contains large deposits of oil and minerals, finding a way to collect them safely and economically would prove to be very profitable.