70% of coral in Okinawa’s Sekiseishoko area dead, survey shows

JIJI Japan Times 11 Jan 17;

About 70 percent of the coral in the Sekiseishoko area, the largest coral reef in Japan, is dead, an Environment Ministry survey has found.

A ministry official said Tuesday the result showed accelerated coral bleaching was taking place — due chiefly to rising ocean temperatures.

The survey was conducted at 35 points in Sekiseishoko, located between Ishigaki and Iriomote islands in Okinawa Prefecture, last November and December.

Coral bleaching occurs due to an inflow of red soil to the ocean and seawater contamination, as well as higher water temperatures, officials at the ministry’s Ishigaki Ranger Office in Okinawa said.

The bleaching at Sekiseishoko worsened between June and September last year because ocean temperatures were 1 to 2 degrees Celsius higher than normal, topping 30 C.

Coral dies if it remains bleached for a long periods.

According to the survey, 91.4 percent of the coral in the surveyed locations is at least partly bleached.

Coral bleaching kills 70 percent of Japan’s biggest coral reef
TATSUYUKI KOBORI Asahi Shimbun 11 Jan 17;

Coral bleaching has killed 70.1 percent of the nation’s largest coral reef as of the end of 2016, up from 56.7 percent just a few months earlier, the Environment Ministry said.

Warmer seawater temperatures last summer are believed to have caused coral bleaching to spread to 90 percent of the Sekiseishoko coral reef in Okinawa Prefecture.

The ministry report, released on Jan. 10, was based on a study conducted in November and December on conditions at 35 points in the Sekiseishoko coral reef, a popular diving area covering about 400 square kilometers between Ishigakijima and Iriomotejima islands.

The previous figure of 56.7 percent was based on a survey conducted in September and October.

Coral bleaching occurs when warmer water temperatures cause coral to expel algae living symbiotically within. The coral turns white and can die.

In the Sekiseishoko area, widespread coral bleaching occurred in 1998 and 2007. Experts warn that the phenomenon could occur more frequently if global warming progresses.


Almost 75% of Japan's biggest coral reef has died from bleaching, says report
Coral in the Sekisei lagoon in Okinawa has turned brown and is covered with algae, according to a government study
Justin McCurry The Guardian 12 Jan 17;

Almost three-quarters of Japan’s biggest coral reef has died, according to a report that blames its demise on rising sea temperatures caused by global warming.

The Japanese environment ministry said that 70% of the Sekisei lagoon in Okinawa had been killed by a phenomenon known as bleaching.

Bleaching occurs when unusually warm water causes coral to expel the algae living in their tissues, causing the coral to turn completely white. Unless water temperatures quickly return to normal, the coral eventually dies from lack of nutrition.

The plight of the reef, located in Japan’s southernmost reaches, has become “extremely serious” in recent years, according to the ministry, whose survey of 35 locations in the lagoon last November and December found that 70.1% percent of the coral had died.

The dead coral has now turned dark brown and is now covered with algae, the Yomiuri Shimbun said.

The newspaper said the average sea surface temperature between last June and August in the southern part of the Okinawa island chain was 30.1 degrees centigrade – or one to two degrees warmer than usual – and the highest average temperature since records began in 1982, according to the Japan meteorological agency.

The ministry report follows warnings by the Coral Reef Watch programme at the US National Oceanic and Atmospheric Administration that global coral bleaching could become the “new normal” due to warming oceans.

Experts said that bleaching had spread to about 90% of the Sekisei reef, a popular diving spot that covers 400sq km.

A similar survey conducted in September and October last year found that just over 56% of the reef had died, indicating that bleaching has spread rapidly in recent months.

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