'White syndrome' threatens coral reefs

The world's coral reefs are seriously threatened by a new disease called "white syndrome ". The disease has appeared in coral reefs in Australia and Okinawa Prefecture (Japan).

Although the cause of the phenomenon has not been determined, scientists warn that " white syndrome " is an infectious disease and that infected coral reefs can die within a year.

The disease called " white syndrome " is affecting coral on Kerama Island, Okinawa Prefecture (photo: Asahi)

According to Akiyuki Irikawa, Japan's coral ecosystem expert, about 30% of the corals around Kerama Island, west of Okinawa, have been affected by the " white syndrome ". White strips spread about 20 cm on the coral surface on average within a month, causing coral reefs to die.

In 2003, the disease also affected Japan's largest coral reef between Ishigakishima island and Iriomotejima island.

According to scientists, in the past decade, there have been many diseases affecting the world's coral reefs.

The report of the Intergovernmental Committee on Preventing Climate Change, released in April, warned that most coral areas will be affected by white bands if the water temperature rises from 1 -2 degrees Celsius compared to 1990 temperatures, and a large number of corals will die if the water temperature increases by more than 2 degrees C. The United Nations Environment Program (UNEP) also cautions that about 30 percent of coral reefs The world has been seriously destroyed and it is likely that 60% of coral reefs will disappear by 2030.

There are about 284,000 km ^{2 of} coral in the world, accounting for about 1.2% of the continental shelf area. Coral reefs play important roles such as supporting the fisheries and tourism sectors, and working as natural breakwaters to prevent high waves when storms occur. In addition, coral reefs also contribute to the diversification of ecosystems. According to UNEP estimates, the economic value of a kilometer of coral is estimated at 100,000 to 600,000 USD / year.