Cyclone's cool wake spurs 'incredible recovery' in Great Barrier Reef coral

Cooler waters brought by Cyclone Alfred have spurred a remarkable recovery in the Great Barrier Reef's southern reaches. Around Lady Elliot Island, the reef's southernmost coral cay, approximately 90% of coral that suffered bleaching in the summer of 2024 has returned to good health.

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The water temperatures dropped about 2 degrees Celsius.

Marine biologist Erin Watson described the transformation, noting that water temperatures dropped by about 2 degrees Celsius. "Now if you go out for a snorkel, the corals that did bleach, you wouldn't even notice had bleached in the first place," she said. This recovery is particularly significant as 2024 marked the first time much of the southern reef experienced widespread bleaching.

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Now if you go out for a snorkel, the corals that did bleach, you wouldn't even notice had bleached in the first place.

Scientists are now eagerly awaiting a coral spawning event later this year, a sign of the reef's resilience. However, the recovery is not uniform across the entire World Heritage marine park. The Australian Institute of Marine Science reported that the 2024 bleaching event was the most severe and extensive in its 40 years of monitoring, causing substantial mortality and significant declines in coral cover in other areas.

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If those environmental conditions like water temperature start to go back down again, the coral takes back its algae and it recovers.

Cyclones like Alfred are considered a double-edged sword. While they can provide a crucial "cooling wake" effect, their associated storm swells can also cause physical damage to the reef structures.

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They're known to have what's called this 'cooling wake' effect and can reduce the temperature of the water.