Citizen scientists discover a Great Barrier Reef coral giant ‘like a rolling meadow’ | Great Barrier Reef

Citizen scientists have discovered what they believe is one of the largest coral colonies ever documented on the Great Barrier Reef.

The maximum length of the coral is approximately 111 meters and covers an estimated area of ​​3,973 m2; This is about half the size of a football field.

pavona clavus The coral was first found by Jan Pope in waters a few hours off Cairns. It was identified as part of the Great Reef Census, a citizen science project run by Reef Citizens.

“It was quite glassy and I could see a very strange pattern in the water,” Pope said. “When I jumped into the water it became clear to me that I had found something, I had never seen anything like it before.”

Pope, who has been diving the Great Barrier Reef for 35 years, described it as “a very surreal underwater landscape. It looks like an undulating meadow.”

The Pope’s daughter, Sophie Kalkowski-Pope, explored the site with her mother two weeks later. “We didn’t know that something this important was on our doorstep,” he said.

Kalkowski-Pope, marine operations coordinator for Citizens of the Reef, said the census project used crowdsourced imagery to monitor coral cover on the Great Barrier Reef. The organization estimates it has explored a quarter of the reef since 2020.

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Kalkowski-Pope said the goal of the project is to identify key resource reefs, which are “resilience hotspots” that could provide larvae when they spawn on other reefs.

Dr Queensland Museum coral curator, who was not involved in the research. Tom Bridge said: pavona clavus It was a rare and “pretty hard to find” coral. “But where [found]”It can form really, really ridiculously large colonies,” he said.

In 2024, just over 1,000 square meters of coral of the same species was discovered in the waters of the Solomon Islands.

Bridge, who is also a senior lecturer at James Cook University, said: “Very large coral colonies will be extremely rare because we are seeing increasing frequency as well as severity of bleaching.”

For a coral colony that is dozens or hundreds of years old, the chances of escaping bleaching conditions or being robust enough to withstand hot water diminish, he said.

But Bridge added that genetic testing is needed to confirm whether the Cairns corals are truly a single colony, meaning they all formed from a single original polyp.

Another possibility is that, instead of being a single individual, the coral consists of multiple colonies that settle in close proximity to each other and come together as they grow.

For genetic testing, “we will need more than 300 individual samples because the colony is so large,” Kalkowski-Pope said.

To estimate its size, the coral colony was mapped using a technique known as photogrammetry, in which photographs of coral on the water surface are combined into a 3D model.

Serena Mou, a research engineer at QUT’s Center for Robotics, described mapping as “a slightly interactive process”.

“The coral turned out to be bigger than Sophie originally thought,” he said.

Bridge said coral species are now classified as: pavona clavusIt is set to be reclassified as part of the revision of coral taxonomy.

Another citizen science project called Map the GiantsIt follows giant coral colonies around the world, managed by the Bicocca University of Milan.