Home Technology Is the Great Barrier Reef Healing Itself?

Is the Great Barrier Reef Healing Itself?

New data show that two of the three areas of the Great Barrier Reef have the largest coral cover in 36 years.

Scientists have released the latest statistics on the “coral cover” – the area of ​​a reef covered with living corals – on a world-famous reef off the east coast of Australia.

They showed that the Great Barrier Reef in the north and in the center has increased coral cover over the past year – by 9% and 7%, respectively.

The coral cover in the northern region is now 36% and the coral cover in the central region is 33%.

This is the largest coral cover in the area since 1985, when scientists began monitoring the reef.

However, the average coral cover south of the Great Barrier Reef has dropped to 34% from 38% in 2021.

The new statistics were released by the Australian Institute of Marine Sciences (AIMS), which began monitoring the world famous coral reef in 1985.

Its chief executive, Dr. Paul Hardesty, said the downturn in the south was driven by an outbreak of crown-of-thorns starfish that feed on coral reefs.

“One-third of the increase in coral cover we recorded in the south in 2020/21 was lost last year due to the ongoing outbreak of crown-of-thorns starfish,” he said.

This shows the extent to which coral reefs are subject to persistent acute and severe disturbances that occur more frequently and last longer.

The new data is somewhat surprising because earlier this year the reef suffered its fourth mass bleaching event in just seven years.

During bleaching, the coral loses its symbiotic algae and pigments, causing it to turn white and possibly die. Coral reefs can survive bleaching, but they are under more stress.

There have been five mass bleaching events in total on the Great Barrier Reef – in 1998, 2002, 2016, 2017, 2020, 2020 and 2022 – but the last two were not as severe in terms of coral death, according to AIMS.

This latest data shows that corals can still recover during periods free from major disturbance.

However, Dr. Hardisty added: “In 36 years of monitoring the Great Barrier Reef, we have not seen bleaching events this close together.”

And every summer, coral reefs are at risk of heat stress, bleaching and possible death, and our understanding of how the ecosystem responds is still evolving.

A year ago, AIMS reported an increase in coral cover in all three regions – North, South and Central, indicating that growth in the south region has unfortunately gone in the opposite direction and has since begun to decline.

Coral waves in the northern and central regions were a sign that the reefs were still recovering, but the loss of coral cover in the southern region illustrates the “dynamism” of the entire reef.

Most of the increase in coral cover in the northern and central regions has been caused by fast growing Acropora corals, according to AIMS.

However, these reefs are especially vulnerable to wave damage that can be caused by strong winds and tropical cyclones.

Unfortunately, Acropora corals are very susceptible to coral bleaching when the water temperature rises sharply and are the preferred prey for crowned starfish.

Dr. Mike Emsley, Team Leader for the AIMS Monitoring Program, said: “This means that a significant increase in hard coral cover can be quickly offset by disturbances in Acropora-dominated reefs.

Dr Zoe Richards, a research fellow at Curtin University in Perth, who is not part of AIMS, praised the importance of the new data.

“The finding that coral cover has already reached relatively high levels in the northern and central sectors is good news, as coral reefs are home to thousands of other plants and animals,” she said.

However, as mentioned in the report, this recovery trend is driven by several Acropora species that often grow in a boom and bust pattern.

This means that the next heat stress can easily destroy these coral communities again.

Source: Daily Mail

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