The Mariana Trench: The Absolute Bottom
Everyone knows that the world’s highest peak is the “Mount Everest”, but what about the deepest place on earth?
The Mariana Trench is the deepest place on earth measuring depths of more than 10 kilometres deep (36000 feet), whereas, the world’s highest peak, Mount Everest is about 29000 feet high. So to imagine the scale of this enormous depth, picture a flipped version of the Mount Everest plus an additional 7000 feet (equal to three of the BurjKhalifa building). In this article we will discuss about the geographical and topographic characteristics of the Mariana Trench, how trenches are formed, the history of how it was discovered, and the possibility of existence of life at such immensely great depths.
What are Trenches and how are they Formed?
There are certain connections or “scars” on the face of the earth, namely the crust. The crust is made of plates called “Tectonic Plates”. The material below the crust is a semi solid sea of molten rock. Therefore, the plates can move on this liquid layer (but in the course of thousands of years). When two plates meet each other, the force of their collision can result in one of two situations. Firstly, the edges of the plates collide and fold upwards leading to the formation of “Fold Mountains” (much like the Himalayas). You can observe this if you push two soft bound notebooks against each other on a table. The other option is that they fold downwards (one plate slides below the other into the mantle layer) to form trenches. Trenches requires some external force so that they fold downwards. The immense pressure exerted on the ocean floors by the water supports this necessity. Therefore trenches are conventionally found in the Oceans rather than on land. The Mariana Trench is one of a global network of oceanic trenches. It is in a crescent shape.
It is located in the Western Pacific Ocean towards the eastern side of Philippines. A group of islands called the Mariana Islands are located 200 kilometres west of the Mariana Trench. It is crescent shaped scar on the face of earth. At this trench, the Pacific Ocean dives under the Philippine tectonic plate. Given below are some of the details of the Mariana Trench.
Length: 2550 kilometres
Width: 69 kilometres
Deepest Point: Challenger Deep (36,070 feet or 11 kilometres deep measured from the ocean surface)
The “Challenger Deep” is the deepest point on the earth’s crust and is located 322 kilometres south west of the US territory Guam. As of today a major portion of the Mariana Trench is a US protected zone under the Marianas Trench Marine National Monument under the order of the then American President George W. Bush.
The Discovery of the Mariana Trench
These great oceanic depths were first investigated by a British Vessel, the “H.M.S Challenger” in the year 1875, which was a part of the world’s first oceanographic cruise. The scientists present on board used a weighted sounding rope to measure the depths. They measure the time a triggered sound to reach them and determine the depth since they know the velocity of sound. It was first measured to be 4,475 fathoms (approximately 8 kilometres).
Seventy Six years later in 1951, its successor, the “H.M.S Challenger-II” returned to the Mariana Trench with a more accurate means of depth measurement instruments (an echo sounder). This time the depth was measured to be a little more than ten kilometres. The deepest point on the surface of earth, the “Challenger Deep” was named in honour of the challenger vessel.
Thousands of climbers have scaled the great heights of the Mount Everest but few have dared to go as deep as the “Challenger Deep”. For starters, the conditions at such great depths are far more dangerous than that of Mount Everest. The temperatures are just above the freezing point and the pressure exerted by the ocean is a crushing eight tons per square inch! Any vessel which goes to such a great depth must be built with extra tough materials to withstand such a pressure.
The first ever pair to have descended to the challenger deep were Jacques Picard and US Navy Lieutenant Don Walsh. They successfully did so in the Swiss Designed US Navy Submersible, the “Trieste”on January 23rd, 1960. It took them five hours to descend to the bottom. Afterwards they spent a mere twenty minutes and were unable to take any photographs due to the cloud of silt that covered them when the submersible landed. At an instant in his journey their floodlight illuminated a flat fish which proved to be an important finding in the mission proving the existence of life in the Mariana Trench.
Recently on 26th March, 2012, Oscar winning film director, James Cameron made a solo descent in a specially engineered DSV (Deep Submergence Vehicle) Deep Sea Challenger. It took the vehicle 2 hours and 36 minutes to reach the bottom which recorded a depth of 10,898.4 meters. The original plan was to spend six hours exploring the ocean floor but he had to return to the surface earlier due to hydraulic fluid leak leading to acceleration systems failure. He spent 2 hours and 34 minutes on the ocean floor exploring and reported that the surface he landed on soft, gelatinous looking flat plain and found no living thing larger than an inch. It took him 90 minutes to surface back.
Life at the World’s Greatest Depths
Many more descents are being planned for the current year. But after these successful descents scientists have debated about the existence of life at places where metal can fracture simply. But many types of clams and smaller amphipods which small shrimp like scavengers. Many unmanned deep sea missions have uncovered the existence of exotic life forms like translucent fishes and many more which are yet to be discovered.
Awaiting in the Deep
Scientists believe that the life at the bottom of the sea can drastically improve research in the fields of medicine and biotechnology since the creatures should have some sort of mechanism to resist the high pressures and low temperatures. These creatures can also shed light on the evolution of life on earth or even the existence of microorganisms which existed at the very beginning. The mud volcanoes present at the bottom are perfect for supporting the very first life forms that came into existence on earth. Additionally the rocks and patterns can provide some explanation to the devastating tsunamis caused in the Pacific Rim.