Massive 'detached' reef first of its kind discovered in over 120 years
Researchers in Australia have uncovered a massive “detached” coral reef off the Queensland coast, the first of its kind to be discovered in more than 120 years. The discovery was made about 80 kilometres east of Cape Grenville, approximately 150 kilometres south of the tip of the Cape York Peninsula.
Estimated to be up to 20 million years old at its deepest part, it was discovered during a 12-month mapping project of Australia's oceans. A "detached" reef refers to a reef bedded to the ocean floor but not part of the main Great Barrier Reef structure. At nearly 500m in height, it is home to a thriving ecosystem of coral, fish and shark species.
According to Dr. Beaman, detached reefs act as isolated seamounts. With extensive deep water separating it from the next coral community, they have the potential to evolve unique species. "We are surprised and elated by what we have found," said research leader Robin Beaman from James Cook University (JCU). "When we got to the crest of it—it's only about 300 by 50 metres wide—we found a lot of fish and a healthy shark population too."
The team has been exploring the reef using an underwater robot called "SuBastian", which utilises a remotely controlled arm able to collect samples for identification "As a collective over the entire [12-month] expedition, we've been finding a whole lot of new species," said Beaman. "It's going to take time for us to work through the imagery and samples we've collected before we can say if there are new species [at this reef] or not."
The researchers discovered evidence of new reef-building within the photic zone, which extends down to around 200 metres. The photic zone, where enough sunlight penetrates to provide direct energy via photosynthesis, would have moved up and down the reef over time as sea levels fluctuated. During the last ice age when oceans were around 120 metres lower than today, some of the reefs would have been in much shallower water or even exposed.
The announcement is welcome news after a recent study declared half the Great Barrier Reef’s corals to have died since 1995 as a result of coral bleaching. That study’s co-author, reef scientist Terry Hughes of James Cook University, said the extent of these deep reefs, known as mesophotic reefs, is being revealed due to recent advances in technology. “Mesophotic reefs—reefs deeper than 30 metres—it turns out there's probably at least as much coral habitat below 30 metres as there is above it, and people are still mapping it,” said Hughes.