The World’s Deepest Mystery BY: ANANYA ARAVINDAN

WHAT MAKES THE MARIANAS TRENCH SO UNEXPLORED?  Extreme cold  Highly pressurized  Total darkness  Currents  No Oxygen  Floor has hydrothermal (hot water) vents and the temperature around the vents can reach 300◦C

CLIMATE AND LOCATION The Marianas Trench is located in the western Pacific, east of the Philippines. It is a crescent shaped scar in the earth’s crust (over 1,500 miles). The relatively warm water of the Pacific Ocean stretches to the depths of 500 to 1,000 feet. After that the water forms something known as thermocline in which the water temperature drops rapidly. The thickness of this varies anywhere from 1,000 to 3,000 feet. After that the water cools more slowly. At the bottom of the Marianas Trench the water temperature is anywhere between 1-4◦C, just above freezing.

WHY IS EXPLORING THE MARIANAS TRENCH IMPORTANT? The ocean area is much of the biosphere, yet we know more about the surface of the moon and Mars than we do about the depths of our own world. There are many important discoveries waiting to be found in the Marianas Trench. For example in 1977 we discovered hydrothermal vents and their organisms which revolutionized our ideas about energy sources and the adaptability of life. Scientists have found new species such as shrimp-like amphipods, and strange, translucent animals called holothurians. Scientists are particularly interested is microorganisms as they may lead to breakthroughs in biomedicine and biotechnology. Also they might shed light on the emergence of life on Earth. Additionally, studying rocks from ocean trenches can help understand the earthquakes that cause the powerful and devastating tsunamis around the Pacific Rim.

JOURNEY DOWN DEEP On March 26, 2012 James Cameron piloted the Deepsea Challenger submersible to the Challenger Deep of the Marianas Trench. It was the world’s first extensive scientific exploration in a manned submersible. The Deepsea Challenger was custom built for this adventure and he was the sole occupant. The pilot sphere was so small that James Cameron could not even extend his arms. While he was there he filmed footage for a feature length documentary and he also collected samples for research. This journey was part of the Deepsea Challenge which is dedicated to advancing the world’s knowledge about our deepest wonders.

DEEPSEA CHALLENGER

TOOLS AND TECHNOLOGY There have been advances in observational equipment like fiber optic LED lights and low light cameras which have increased our understanding of deep sea creatures in their habitat. These observational devices may be attached to permanent sub-sea stations which are connected to land via fiber optic cables or on lander devices which are dropped to the sea floor, then picked up later. There are also ROV’s (Remotely Operated Vehicle) which have video and still cameras attached and mechanical arms for picking specimens up. Then there are AUV’S (Autonomous Underwater Vehicle) which also have cameras but are preprogrammed to operate without cables. USA’s Nereus was the first unmanned submarine to reach the deepest trenches. This submarine could switch from ROV mode to AUV mode! Finally there are manned deep-sea submersibles. Alvin was one of these and he was built in 1964 in America and was used extensively. It had mechanical arms, cameras, could hold3 people, and went on more than 400 dives reaching a maximum depth of 4,500 meters.

HOW HAS CANADA HELPED? Though Canada has not directly helped build the tools to explore the Marianas Trench we have helped build tools to explore other areas of the ocean. The ISE (International Submarine Engineering) company has recently helped build some AUV’s to explore underneath the Arctic ice, north of Canada. One of those is the Arctic Explorer which is a derivative of the successful Explorer AUV that was first designed in ISE has built two Arctic Explorers for Natural Resources Canada to map the sea floor underneath the Arctic ice. In April 2010, one of these vehicles completed over 1000 km of under-ice survey, mapping the sea floor during 10 days of continuous underwater operation. Also ISE has built AUV’s for the Memorial University of Newfoundland in Canada and University of Bremen in Germany. They also built an Explorer for the National Oceanic and Atmospheric Agency in the USA.

WILL IT LAST? Even though the Marianas Trench is rather unexplored it is still in danger of pollution. On James Cameron’s recent adventure to the Challenger Deep, his deep-sea submersible had a hydraulic fluid leak. Hydraulic fluids are liquids that are used as the motive medium in hydraulic machinery and equipment. When Hydraulic fluid is heated to it’s flash point, sprayed, or vaporized it becomes highly hazardous. This could very well happen at the Challenger Deep as there are thermal vents on the sea floor which can reach a high of 300◦ C.

WILL IT LAST? However because of the current interest in protecting the environment, scientists have developed biobased and biodegradable hydraulic fluids. These biobased fluids help to minimize pollution in the case of an oil leak. In order to explore the Marianas Trench responsibly and help lessen the risk of pollution we can use these biobased fluids instead of the regular ones. Another threat to the environment is the studying of microbes. It has proven difficult because it’s nearly impossible to bring up the sediment without raising its temperature and de-pressurizing it, which can kill organisms adapted to such conditions. To overcome this obstacle, scientists from Germany and Japan devised instruments to study the organisms in their place at the sea floor.

FUN FACTS The Marians Trench is 36,070 feet deep If Mount Everest was dropped into the Marianas Trench, it would still be a mile under water The deepest point is called the Challenger Deep The pressure at the Challenger Deep is 11,318 tons per square meter (that’s the equivalent of one person trying to hold up 50 jumbo jets) More people have been on the moon than at the bottom of the Marianas Trench

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PICTURES Marianas Trench

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