Around 70 percent of Japan’s largest coral reef, the Sekisei lagoon in Okinawa, has died by a phenomenon known as bleaching.
A recent report from the Japanese environment ministry, says this is due to rising sea temperatures caused by global warming, Sea temperatures have dropped since, but full recovery of live bleached corals remains unclear.
According to the Japanese environment ministry, approximately 70 percent of the Sekisei lagoon in Okinawa, Japan has died from bleaching.
Bleaching is a phenomenon, which occurs when unusually warm temperatures trigger corals to release the algae inside their tissues.
This causes them to become completely white. This is an adaptive response, since the white color reflects sunlight better, therefore reducing the heat absorption into the corals.
Since these expelled algae are what supply the corals with nutrients, if temperatures do not return to normal, the corals eventually die from lack of nutrition. Bleaching also makes the corals more vulnerable to predators and disease.
According to the Japanese environment ministry, the reef’s conditions have become “extremely serious” in recent years. The ministry carried out a survey of 35 locations in the lagoon last November and December, finding 70.1 percent of the coral had died from bleaching. The report also says that more than 91 percent of the reef is at least partially bleached.
Ministry officials have told NHK News that water temperatures have been dropping since the study, however, it is still unclear whether the bleached corals will fully recover.
This follows from a recent “mass bleaching event” last August in Australia’s Great Barrier Reef, where just over 67 percent of the corals died in one area.
These events mark another alarming sign of the dangers of global warming. Last Decembers, temperatures in the North Pole had reached melting point, where a large crack in an Antarctic shelf will be cracking off.