The basic physical principle allowing a submersible to function is buoyancy. The high pressures at the ocean floor also make it difficult for deep-sea submersibles to dive and resurface. Thus, in order to reach the bottom of the Mariana Trench, a vessel such as the Deepsea Challenger needs to be able to withstand over 16,000 psi of pressure to avoid being crushed like a tin can. At this depth, the pressure is 5,540 pounds per square inch (psi), or 377 times sea level pressure. At the average ocean floor depth of 12,200 feet, there is a column of water more than 2 miles high pressing down on the sea floor and any submarine that travels there. Through hydrostatic pressure, water pressure increases in proportion to the height of the water in the column, and the water at the bottom has to support the weight of the incompressible fluid. However, the largest problem facing deep-sea submersibles is the incredible pressure at the bottom of the ocean, known as hydrostatic pressure. For example, electrical fires, loss of power, or mechanical failures could leave the pilot trapped in the near-freezing depths of the ocean without light or much oxygen. A deep-sea submersible faces the same problems as any other conventional submarine. 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.Īlthough exploring the ocean floor would greatly benefit society, charting the depths of the sea is no easy task. Scientists hope to analyze the DNA of these organisms and other sea creatures in order to understand how they function. These bacteria provide an energy source for other life forms and allow a unique ecosystem to thrive near these deep-ocean vents. 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. Consequently, organisms living near the sea floor cannot use the sun as a source of energy and have developed unique alternatives to sustain themselves. The average depth of the ocean floor is 12,200 feet, with sunlight penetrating only 1,000 feet below the waves. 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. 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. 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. Subduction zones are responsible for most of the active volcanoes on earth as well as most major earthquakes and tsunamis. Why bother exploring the ocean floor?įigure 1: The process of subduction involves the movement of one tectonic plate sliding beneath a second one. 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.

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. 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. His vessel, Deepsea Challenger, took seven years to build and was designed specifically to reach the bottom of the Mariana Trench.

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. 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. 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.

Mariana trench trieste submarine