Coral colony could be world's largest discovered by mother and daughter citizen scientists

What began as an ordinary recreational dive off the coast of far‑north Queensland by a mother and her daughter has become a striking reminder that the Great Barrier Reef still holds surprises. The pair, participating in a citizen science survey, say they have identified what may be the largest known coral colony on Earth — a living structure stretching more than 100 metres across the seafloor.

The discovery was made by Sophie Kalkowski‑Pope and her mother, Jan Pope, while they were surveying reef health as part of a national coral census. Swimming through powerful tidal currents near Cairns, they encountered an immense formation of Pavona clavus, a slow growing coral species that rose and folded across the ocean floor like a submerged landscape rather than a single organism.

“It was immediately clear that this was something extraordinary,” Ms. Kalkowski‑Pope told media about the moment the scale of the colony came into view. The coral appeared to extend well beyond the limits of visibility, forming broad, undulating plates alive with fish and other reef species. Subsequent dives confirmed the impression: the colony spans roughly the length of a soccer field and covers nearly 4,000 square metres.

After the initial sighting late last year, the pair returned with measuring equipment and aerial drones to document the structure in detail, producing a three-dimensional map of its shape and size. While large coral formations have been recorded elsewhere in the Pacific, scientists familiar with the new data say the scale of this single, continuous colony is unprecedented, at least among those formally measured and verified.

Marine researchers note that the find offers a rare counterpoint to years of grim headlines about mass bleaching and reef decline. Experts at national research institutions believe the coral may be several centuries old — evidence that, in certain locations and under the right conditions, reef systems can persist despite rising ocean temperatures, cyclones and other acute stresses.

For the Pope family, the discovery carries a more personal meaning. Ms. Pope, who has spent decades diving, said the moment underscored the value of curiosity and volunteer science. Authorities have been informed of the colony’s location, which will remain confidential, and responsibility for its protection has been transferred to reef managers. Even now, the younger Ms. Kalkowski‑Pope said, the full significance of what they found has yet to sink in.

Read more on this story from the ABC here.