Encounters with Atolls and Reefs of the Indian and Southwest Pacific Oceans
Encounters with Atolls and Reefs of the Indian and Southwest Pacific Oceans Review by Geoff Walker To those who have not seen an Atoll, they may ask what it is, well, an Atoll is a circular-shaped coral reef, island, or series of islets, which surrounds a body of water called a lagoon. Sometimes, Atolls and lagoons encompass a central island. Channels between islets connect a lagoon to the open ocean or sea. They are best observed in tropical regions, particularly in the Indian Ocean as well as the central and south west Pacific Ocean. They come in all sizes, some are minute, whilst others are massive in area, thus providing large, safe, protected anchorages. Some are well renowned, whilst others have never been heard of, and are little more than a miniscule notation or “dot” on an Admiralty Chart. There is a tendency for Atolls to form into clusters or groups and they can be a serious hazard to surface navigation. Many have taken their toll on unwary mariners, and which bear the evidence by numerous shipwrecks; a few of which are captured in this account. The formation of an Atoll is a slow process that can take millions of years. It starts when an underwater volcano erupts, creating a buildup of lava on the seafloor. With the passage of time, and continued eruptions, the lava continues to build until it breaks through the ocean's surface and forms an island. With the passage of time, hard corals begin to build a limestone reef around the island. Once the outer reef is formed it is called a “Fringe Reef” and encircles the recently created island, just below the ocean surface.
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