The Greatest Reef? Immense Reef Found Behind Great Barrier Reef

Researchers used high resolution laser data to discover a huge swath of 200-300 meter donut shaped circular mounds composing a reef behind the Great Barrier Reef.

The Royal Australian Navy provided the data gathered from LiDAR-equipped aircraft. Scientists from James Cook University, University of Sydney and Queensland University of Technology worked together to analyze the seafloor data.

"We've known about these geological structures in the northern Great Barrier Reef since the 1970s and 80s, but never before has the true nature of their shape, size and vast scale been revealed," James Cook University's Dr. Robin Beaman said in a release.

"The deeper seafloor behind the familiar coral reefs amazed us."

This amazing seafloor is made up of fields of Halimeda bioherms, the donut shaped circular mounds. A common green algae called Halimeda, grows and forms the reef like bioherm structures.

Halimeda is made of calcified parts. When it dies, it becomes small white flakes of limestone. The build up of the flakes is responsible for the large size of the bioherms.

Geographically, the fields of bioherms go from the Torres Strait to Port Douglas. The depth of the bioherms is up to 10 meters.

"As a calcifying organism, Halimeda may be susceptible to ocean acidification and warming. Have the Halimeda bioherms been impacted, and if so to what extent?" associate professor from the University of Sydney Jody Webster said in the same release.

Less is known about deeper seafloor and how it is affected by climate change compared to the more well known and studied reefs. Mapping the Halimeda bioherms is a first step toward familiarization with some of the deeper seafloor.

Dr. Beaman is already planning future research of the structures. Preliminary plans include sediment coring, sub-surface geophysical surveys, and employing autonomous underwater vehicle technologies to unravel the physical, chemical and biological processes of the structures.