Monday, April 29, 2013

Underwater Ecosystems and their Importance

By Alexis Bracey


Most fish have a special part inside their bodies called a swim bladder. Air inside the swim bladder helps the fish float through the water. The fish can adjust how much air is in its swim bladder. If it wants to swim deeper, it lets some air out and if it wants to swim up towards the surface, it will let more air into its swim bladder.

In 1960, a descent was made to 10,916 m/35,813 ft in the Challenger Deep external of the Marianna trench-the deepest known point in the oceans, 10,924 m/35,838 ft deep at its maximum, near 11 22'N 142 36'E-about 200 miles southwest of Guam. The dive was made in the bathyscape Trieste external built by Auguste Piccard, his son Swiss explorer Jean Ernest-Jean Piccard and U.S. Navy Lieutenant Don Walsh. The descent took almost five hours and the two men spent barely twenty minutes on the ocean floor before undertaking the 3 hour 15 minute ascent.

Another important dive was the Trieste. The Trieste's first dive was made in 1953. In the years following, the bathyscape was used for a number of oceanographic research projects, including biological observation, and in 1957 she was chartered and later purchased by the U.S. Navy. The Navy continued to use the bathyscape for oceanographic research off the coast of San Diego, and later used the Trieste for a submarine recovery mission off the U.S. east coast. The bathyscape was retired following the U.S. Navy's commission of the Trieste II external, and is currently on exhibit at the Washington Naval Historical Center external.

Today, the possibilities for ocean exploration are nearly infinite. In addition to scuba diving, rebreathers, fast computers, remotely-operated vehicles (ROVs), deep sea submersibles, reinforced diving suits, and satellites, other technologies are also being developed. But interdisciplinary research is needed to continue building our understanding of the ocean, and what needs to be done to protect it. In spite of ongoing technological advances, it is estimated that only 5% of the oceans have been explored. Surprisingly, we know more about the moon than we do the ocean. This needs to change if we are to ensure the longevity of the life in the seas-and they cover 71% of the earth's surface. Unlike the moon, they are our backyard. Without a detailed collective understanding of the ramifications of pollution, overfishing, coastal development, as well as the long-term sustainability of ocean oxygen production and carbon dioxide and monoxide absorption, we face great risks to environmental and human health. We need this research so that we can act on potential problems-not react to them when it is already too late.

Marine mammals need to come to the water surface to breathe, which is why the deep-diving whales have blowholes on top of their heads, so they can surface to breathe while keeping most of their body underwater. Whales can stay underwater without breathing for an hour or more because they make very efficient use of their lungs, exchanging up to 90% of their lung volume with each breath, and also store unusually high amounts of oxygen in their blood and muscles when diving.




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