Sunday, April 14, 2013

Learn about Marine Life

By Alex Bruce


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.

Sharks look a lot like marine mammals, but they are actually fish! Unlike most fish though, sharks do not have bones. Their skeletons are made up of cartilage instead of bones. Cartilage is the same stuff that makes your ears and the tip of your nose have their shape and be a little bit flexible. Even though they don't have bones, sharks do have lots of other similarities to bony fish. They are cold-blooded and breathe through gills instead of through lungs. Sharks have gills on each side of their heads. As they swim, water passes over the gills and oxygen flows in from the water.

Sharks have several rows of sharp pointed teeth and powerful jaws to tear off big pieces of food, which they swallow whole. They don't even need to chew their food! Sometimes sharks lose teeth, but when they do, new ones grow in their place. Sharks have several rows of teeth. They eat bony fish, squid, marine mammals, and even sea turtles. They have an excellent sense of smell, which helps them find food. Many sharks eat near the surface of the water, but will also dive down deeper in search of food.

Fortunately, thanks to the work of past and present ocean explorers, the public is increasingly aware of these risks which encourage public agencies to take action and promote research. The efforts of public agencies using a multi-disciplinary approach, together with the efforts provided by numerous private marine conservation organizations that work on issues such as advocacy, education, and research, will help drive the momentum needed to face the challenges of preserving the ocean.




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