Coral bleaching confirmed in Kumamoto
Coral reefs in the Amakusa coastal region in Kumamoto Prefecture, southwestern Japan, are suffering from bleaching similar to that plaguing Australia's world famous Great Barrier Reef, a scientist said Tuesday.
Satoshi Nojima, an associate professor at Kyushu University's Amakusa Marine Biological Laboratory, confirmed bleaching during a survey conducted on three types of coral reef in waters off Ushibuka at a depth of 2-5 meters.
A report released in March by the U.S. National Oceanographic and Atmosphere Agency attributed widespread bleaching around the globe to El Nino weather conditions.
Following the confirmation of widespread bleaching in Japanese waters this year, in particular Okinawa and Kagoshima, the Japanese Coral Reef Society has called for an emergency meeting in November to discuss measures to help the reefs recover, Nojima said.
Coral reefs are made up of coral polyps, tiny organisms with an exoskeleton of calcium carbonate. They are given their brownish color by zooxanthelle algae which attach themselves to the polyps.
In conditions of stress, such as pollution or a rise in water temperatures over 31 C, the coral polyps expel the algae, leaving the coral with a dramatic bone-white appearance.
Since coral reefs derive almost 90% of their nutrients from living organisms produced by the algae through photosynthesis, the expulsion of the algae from corals result in death after about a week for weak coral species and about a month for sturdy ones.
Nojima said partial bleaching occurs yearly in Japan in coral reefs found in shallow waters, especially those near bathing sites around the country where the water temperature rises easily. Bleaching in Okinawa, however, has been observed at depths of 20-30 meters.
Bleaching has also been reported recently in other locations overseas such as the Maldives, Mauritius, Samoa and the Galapagos Islands.
''Typhoons have been sparse this year and changes are taking place with water temperatures remaining at high levels,'' Nojima said. ''It is possible that corals in Okinawa and elsewhere will suffer tremendous damage.''