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The coral bleaching in Lord Howe Island is becoming a "major" issue due to rising ocean temperatures reaching unprecedented levels.
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The coral bleaching in Lord Howe Island is becoming a “major” issue due to rising ocean temperatures reaching unprecedented levels.

Experts are concerned about the high level of ocean warmth, which is causing coral bleaching in certain areas of the Great Barrier Reef. This phenomenon is now impacting the southernmost coral reef at the world-renowned Lord Howe Island, recognized as a World Heritage Site.

Additionally, there is worry that ocean temperatures near Australia’s isolated Norfolk Island may be increasing to harmful levels for its coral, located approximately 1400km east of the Gold Coast in Queensland.

A researcher stated that there are numerous unidentified corals in Lord Howe and Norfolk.

A team of scientists has observed a significant increase in the number of corals experiencing bleaching or discoloration at the Lord Howe reefs, located approximately 600km east of Port Macquarie on the central coast of New South Wales.

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According to Professor Bill Leggat, a researcher specializing in coral at the University of Newcastle, the monitoring of corals at Lord Howe Island has intensified in the past two weeks due to increasing thermal stress, resulting in rapid bleaching.

“We have observed that the majority of vulnerable coral in the bay are experiencing bleaching or loss of color. This was a cause for concern. It marks the beginning of a significant and severe bleaching occurrence.”

When corals are exposed to warm water for extended periods, they may experience bleaching. While certain coral species are more resilient to this process, severe bleaching can lead to the death of the organism. Researchers have found that corals that manage to “recover” from bleaching are more prone to diseases and do not reproduce as effectively in the subsequent years.

Unfortunately, the bleaching is occurring due to increasing global ocean temperatures, which are currently setting new heat records. This comes after a significant bleaching crisis that affected reefs throughout the Americas during the previous northern hemisphere summer.

The Great Barrier Reef Marine Park Authority is planning to conduct comprehensive aerial surveys of the largest coral reef in the world following the confirmation of significant coral bleaching in the southern region of the park last week.

Information from the US government’s Coral Reef Watch indicates that the level of heat stress building up on corals in the southern region of the Great Barrier Reef has reached its peak since monitoring began in 1985.

Coral bleached white in the waters off Lord Howe island.View image in fullscreen

The officials have reported that there has been mild to moderate coral bleaching in all parts of the reef. However, they will only evaluate the extent of the damage after conducting full aerial surveys and additional in-water monitoring.

The corals on Lord Howe Island cover a distance of approximately 4km in a bay located on the island’s western side. According to Leggat, there were two documented instances of bleaching in 2010 and 2019.

According to data from Coral Reef Watch, the current level of heat stress affecting corals this year has surpassed that of the 2019 event and is approaching the highest level recorded in 2010.

“It’s frightening to think that it’s already hot and there are forecasts for several more weeks of warm weather. This could potentially surpass the intensity of the 2010 event. The thermal strain will persist and likely worsen.”

The reef system is expertly managed, but is facing significant challenges from climate change. This is a frightening reality. The system, which is typically protected from other threats, is now being heavily impacted by coral bleaching.

According to Coral Reef Watch data at Norfolk Island, heat stress levels have exceeded those recorded during the only other known bleaching event in 2020.

In 2010, there was an increase in heat stress levels. However, according to Professor Tracy Ainsworth, a coral scientist at the University of New South Wales who is involved in monitoring corals at Norfolk Island, this event was not under the observation of scientists.

She stated that we are once again headed towards a situation similar to that of 2020 and in the next few weeks, we may see bleaching occurring.

The situation is worrisome because the heat stress could persist for an entire month, making it potentially the worst event for the reef.

Andrew Baird, a coral researcher at James Cook University, has been examining the corals in Lord Howe and Norfolk. He approximates that 20% to 50% of these corals have yet to be officially documented.

He stated that if Lord Howe or Norfolk suffer severe bleaching, certain species may disappear before their descriptions are completed.

Source: theguardian.com