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| | | How Do Stony Corals Grow? |
Maintained by NOAA
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| | How Do Stony Corals Grow? | | | | Most stony corals have very small polyps, averaging 1 to 3 millimeters in diameter, but entire colonies can grow very large and weigh several tons. As they grow, these reefs provide structural habitats for hundreds to thousands of different vertebrate and invertebrate species. The skeletons of stony corals are secreted by the lower portion of the polyp. This process produces a cup, or calyx, in which the polyp sits. The walls surrounding the cup are called the theca, and the floor is called the basal plate. Periodically, a polyp will lift off its base and secrete a new basal plate above the old one, creating a small chamber in the skeleton. While the colony is alive, CaCO3 is deposited, adding partitions and elevating the coral. Coral species number in the thousands, and stony corals take on several characteristic forms. Reefs form when polyps secrete skeletons of calcium carbonate | | | | |
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| Asian cities head global list of flood vulnerability
by Ives, Mike, SciDevNet 02 March 2012 | |
| | The rapid growth of cities across the developing world has resulted in urban areas overtaking rural communities as being the most vulnerable to widescale flooding, according to a report from the World Bank. | |
Read more at http://www.scidev.net/en ... lity.html.
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