James Cook University, University of Sydney and Queensland University of Technology scientists working with laser data from the Royal Australian Navy have discovered a vast reef behind the familiar Great Barrier Reef.
JCU’s Dr. Robin Beaman says the high-resolution seafloor data provided by LiDAR-equipped aircraft have revealed great fields of unusual donut-shaped circular mounds, each 200-300 meters across and up to 10 meters deep at the centre.
“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,” he said.
North-westerly view of the Bligh Reef area off Cape York. Depths are cultured red (shallow) to blue (deep), over a depth range of about 50 meters. Bathymetry data from Australian Hydrographic Service.
Dr. Beaman said it was an astounding revelation. “The deeper seafloor behind the familiar coral reefs amazed us.”
The fields of circular donut-shaped rings are Halimeda bioherms, large reef-like geological structures formed by the growth of Halimeda, a common green algae composed of living calcified segments.
These form small limestone flakes on death, looking much like white cornflakes. Over time these flakes build up into large reef-like mounds, or bioherms.
Mardi McNeil from Queensland University of Technology and lead author on the new research paper, said their extent is vast.
“We’ve now mapped over 6000 square kilometers. That’s three times the previously estimated size, spanning from the Torres Strait to just north of Port Douglas. They clearly form a significant inter-reef habitat which covers an area greater than the adjacent coral reefs.”
Associate Professor Jody Webster from the University of Sydney, said the revelations about the extent of the bioherm field make questions over its vulnerability to climate change even more pressing.
“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?”
Dr. Beaman said the discovery also opened up many other new avenues of research. “For instance, what do the 10-20 meter thick sediments of the bioherms tell us about past climate and environmental change on the Great Barrier Reef over this 10,000 year time-scale? And, what is the finer-scale pattern of modern marine life found within and around the bioherms now that we understand their true shape?”
He said future research would require sediment coring, sub-surface geophysical surveys, and employing autonomous underwater vehicle technologies to unravel the physical, chemical and biological processes of the structures.
Link to paper:
High-res 3D images of the GBR bioherms can be seen here.
*Laser Airborne Depth Sounder (LADS) uses red and green LiDAR technology to rapidly scan the seafloor to depths of about 50 meters, generating a dense grid of depth data points. The bathymetry data are then used by the Australian Hydrographic Service (AHS) to revise the nautical charts used by mariners.
*Marine geologists previously understood the bioherms to form linear, dune-like parallel ridges and troughs, quite different to the complex seafloor now revealed with the benefit of LiDAR and multibeam swath bathymetry data collected in the past few years.
*Less than 15% of the Earth’s oceans deeper than about 200 metres have been mapped using modern surveying techniques.
Reef Subsea Dredging & Excavation Comple
Tritech Gemini Assists Reef Subsea Dredg
Herbicide Runoff Reduced to Great Barrie
Marine Research Application Puts the Ree
University Researcher Grows Oyster Reef
Vast Freshwater Reserves Found Beneath t
Siemens to Construct Factory for Offshor
Legal Challenge to Dump Dredge Spoil Nea
NSU Oceanographic Students Start Crowdso
Until Death Do Us Part: Genetics Reveal
Edgetech & Sonarwiz Training at Subsea T
Reef Subsea Expands into New Port of Bly
Reef Subsea Awarded First German-Waters
Applied Acoustics’ Distributor Conferenc
Reef Subsea Concludes Year with Completi
Sir Richard Branson Joins Guy Harvey in
Roadmap to Recovery to Inform Coral Reef
Great Eastern Group Take Delivery of Sea
Carbon Dioxide Pools Discovered in Aegea
New Study from Florida Tech Finds Pacifi
NOAA: In 2012, U.S. Ocean and Great Lake
Nova Southeastern University Receives Gr
Mote Takes Next Step in Expanding Its In
Odyssey Marine Exploration Goes to Great
Subcon Awarded Contract for Port Macquar
NOAA Awards More Than $8 Million for Cor
David Attenborough Interactive Website H
Remains of Lost 1800s Whaling Fleet Disc
Australia: Artificial Reef Arrives in Po
NASA's CORAL Campaign Will Raise Reef St
EdgeTech Side Scan Sonar Instrumental in
Rich Coral Communities Discovered in Pal
Stanford Scientists Discover Coral Reef
Artifacts Discovered on Return Expeditio
23 Shipwrecks Discovered off Greece
Artificial Reef Society of British Colum
The Sound of a Healthy Reef
NASA Begins Study of Australia's Great B
The Ocean Cleanup to Share Initial Resul
BP Decides Not to Proceed with Great Aus
NOAA Awards $9.3 Million to Advance Cora
Brazilian Navy League Awards Highest Hon
Exploring Vast “Submerged America,” Mari
Scientists have Confirmed the Largest Di
New Exciting Creatures Discovered on the
Great Lakes Receives Award for Coastal R
Sea Floor Erosion in Coral Reef Ecosyste
WSU Researchers Find Wealth of Fish at D
Robots May Bring Reef Relief
Texas A&M-Corpus Christi Testifies on Ar
Great Depths of Opportunities in India f
Proserv to Build New £7million Great Yar
Statoil Announces Revises Plans for the
Scientists and Astronauts Creates World'
Perfect Storm’ led to 2016 Great Barrier
FSU Researcher Makes Deep-Sea Coral Reef
Lost US WWII Submarine USS S-28 Discover