On 12-Dec-2000 obrien wrote: >>> Some scientests are now saying that corals may be >>> largely gone in 25 years >>> due to global >>> warming!!!! >> >>If we lose coral, it will be due to pollution, not > global warming. > > Today I heard on NPR that 2 years ago 10% of the world's > coral was dead. It's now 27%! It's been looked at > extensively and the overwhelming evidence points to warming. > For example, corals grow producing coral growth rings which > can reflect growing conditions. Looking at these rings and > counting back thousands of years shows current El Nino's > at twice the historic rates. These are currently much > more frequent than ever before. These are also likely > to be more extreme as well. Here's the reason why corals are dying with global warming. Corals are very sensitive to changes in temperature because of their physiological nature. A living coral is a symbiosis between two organisms, coral polyps which build the coral, and an algae called zooxanthellae which produce the chemicals that allow polyps to build their limestone skeletons. Unfortunately, zooxanthellae have a very narrow temperature range in which they can live, often as narrow as 0.5 degrees C. When temperatures rise beyond their allowable range, they die off, and the coral reef is bleached (turns white). This is a dead reef. Bleaching is not always permanent. El Nino events often cause bleaching, but the zooxanthellae can repopulate the reef after El Nino has gone away. This kind of bleaching and repopulating has been observed many times. Unfortunately, global warming does not go away from year to year. A reef that is bleached from global warming related temperature rises is permanently dead. And since zooxanthellae are so sensitive to temperature changes, coral is an excellent indicator of global warming. That 25% of the reefs have recently died is a pretty good indicator that global warming is happening. For more info on coral bleaching, there are several articles about this on my website: Glossary explanation of coral bleaching: http://www.yourplanetearth.org/terms/details.php3?term=Coral+Bleaching An article on the 25% of coral reefs already bleached and 70% may be bleached by 2050: http://www.yourplanetearth.org/article.pl?sid=00/12/12/0123204&mode=nested An article about new institutions created to preserve coral reefs, including Clinton's creation of coral reef national monument in Hawaii: http://www.yourplanetearth.org/article.pl?sid=00/12/05/1933222&mode=nested If you like coral reefs, or have never seen one (such as me), go see them soon before they are gone! Kevin For more information For more information ---------------------------------- Kevin Whilden Your Planet Earth http://www.yourplanetearth.org E-Mail: kevin_at_yourplanetearth.org ph: (206) 788-0281 fax:(206) 788-0284 ---------------------------------- *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Wed Dec 13 2000 - 10:34:59 PST
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