Ocean Exploration. Copyright 2012 LessonSnips

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1 Ocean Exploration Approximately 71 percent of the surface of the earth is covered by the ocean yet very little of the ocean has been explored. Once sailing ships capable of traversing the ocean were built, sailors ventured long distances over the surface of the ocean. During the Age of Discovery, which lasted from 1450 to 1650, European explorers sailed around the world searching for sea routes to replace the overland trade routes to India and China. What creatures lived below the surface in the depths of the water were simply termed Mysteries of the Deep which were filled with stories and legends of strange or monstrous creatures. Even as late as the 1850s, Edward Forbes, a British scientist of the time, proclaimed that no creature could survive below 300 fathoms, the equivalent of about 1,800 feet. Early Exploration However, the viewpoints about the ocean and the marine life it holds changed with the Challenger Expedition that occurred between 1873 and This British expedition led by Sir Charles Wyville Thomson was named after its main sailing vessel the HMS Challenger. This naval ship was modified for its worldwide journey of exploration and was outfitted with scientific laboratories for natural history and chemistry. The technique used by Thomson and his team was to dredge the ocean floor and bring up whatever was captured by the dredging. They were able to dredge the bottom at a maximum ocean depth of five miles. In their exploration they proved that life existed in the deep ocean and they also discovered about 4,000 new species of marine organisms. Exploration in the Twentieth Century French author Jules Verne s novel 20,000 Leagues under the Sea, completed in 1870, introduced radical ideas of submarines and diving apparatus that would allow humans to explore the ocean depths. It s important to realize that water exerts pressure on everything below it. The deeper the ocean, the more pressure there is at the bottom. Humans can withstand only so much pressure from the water above before the body is crushed by the pressure. This is why divers must wear a pressurized suit when in the deep ocean. Divers must ascend from deep

2 water at the proper rate or risk developing the debilitating or sometimes fatal disease known as the bends. At the beginning of the Twentieth Century deep dives relied on the emerging technology of pressurized diving apparatus. In 1930 two Americans, Otis Barton and William Beebe, descended 600 feet into the ocean in a bathysphere whose design was commissioned by the wealthy Barton. A bathysphere is a small unpowered underwater craft that is lowered into the ocean for exploration while remaining tethered to a vessel by a cable which lowers and raises it. The duo eventually descended to 3,028 feet and naturalist Beebe was the first to describe the wonders of bioluminescence, the light emitted by deep sea creatures. In 1954 Swiss scientist Auguste Piccard designed the first bathyscaphe, a pressurized undersea vehicle that was untethered. By 1960 the Trieste was a second generation bathyscaphe owned by the U.S. Navy. Piccard s son Jacques and Navy lieutenant Don Walsh descended to the deepest point in the ocean, the Mariana Trench. Their record dive of 35,797 feet has never been equaled. The Trieste descended due to a heavy load of weights placed upon it. In order to ascend the weights were cast off at intervals. The next technological achievement in exploring the deep ocean was the design of a maneuverable submersible by a team of U.S. oceanographers. The craft was named Alvin after Al Vine, the leader of the team. Alvin held three people, two researchers and a pilot. Sophisticated modern submersibles continue to require a trained pilot who ferries researchers to their desired research areas. Alvin was equipped with two robotic arms for collecting samples. Alvin and the French submersible Cyana were involved in a joint effort called Project FAMOUS which explored the Mid-Atlantic Ridge beginning in The Mid- Atlantic Ridge is an undersea volcanic mountain range that runs the length of the Atlantic Ocean from north to south and exists in about the middle of the Atlantic Ocean. Later the explorers moved to the Galapagos Rift in the Pacific Ocean where they discovered hot springs coming from cracks in the rocks on the sea floor as geologists had predicted. Next they explored the East Pacific Rise, an undersea mountain range off the Gulf of Mexico, and off the coasts of Central and South America.

3 During this exploration, researchers discovered hydrothermal vents that exist at the top of undersea chimneys. These chimneys vent gases that originate in the earth s interior. Most astounding, in 1977 they found a host of new species of marine creatures that were thriving in this hostile marine environment of extremely hot temperatures and toxic (to other life) gases. Submersibles are carried on specially equipped research vessels to the desired location of interest. The latest submersibles are equipped with sophisticated robotics that allow the collection of water, sediment and specimens of new marine creatures. Modern unmanned submersibles transmit pictures and data about the ocean waters to computers on board the main vessel. Exploring the deep ocean is an expensive process but at the current time scientists know more about space than they know about the deep ocean and its species. Researchers are discovering new species on virtually every research excursion.

4 Circle True or False after analyzing each of the following statements. 1. True False European explorers sailed around the world searching for sea routes to replace the overland trade routes to India and China during the Age of Reason. 2. True False The Challenger Expedition of the 1870s sailed around the world dredging the ocean floor and discovered thousands of new species of marine life. 3. True False Jules Verne s novel 20,000 Leagues under the Sea introduced radical ideas of submarines and diving apparatus that could allow humans to explore the ocean depths. 4. True False Humans who descend into the depths of the ocean must have a pressurized environment or their bodies will be crushed by the pressure of the water. 5. True False Divers who descend into the deep ocean too quickly will suffer from a disease called the bends. 6. True False A bathyscaphe is a small unpowered underwater craft that is lowered into the ocean for exploration while remaining tethered to a vessel by a cable which lowers and raises it 7. True False Bioluminescence of marine creatures was first discovered in the 1930s. 8. True False The bathyscaphe Trieste s record dive went to the bottom of the Monrovia Trench, the deepest point in the ocean. 9. True False Modern unmanned submersibles transmit pictures and data about the ocean waters to computers on board the main vessel. 10. True False There are marine creatures that thrive in the hostile marine environment of hydrothermal vents.

5 Answers 1. False 2. True 3. True 4. True 5. False 6. False 7. True 8. False 9. True 10. True