Researchers mapping the southern Great Barrier Reef have discovered submerged ancient landscapes, including prehistoric forests and river systems inundated 7,000 years ago.
Around 7,000 years ago, as global sea levels climbed to their present height at the end of the last Ice Age, that plain was inundated. What had been forest and river mouth and estuary became reef. What had been lived-in country became the seafloor. To reconstruct the history of that transformation, the research team collected more than 20 sediment cores from the seabed. Those cores allowed researchers to piece together the historical climate, vegetation, and sea level changes that shaped the region over millennia in a process known as palaeo-environmental reconstruction.
Seafloor Sediment Cores as Historical Time Capsules
The collection of seabed samples serves a precise scientific purpose. “Seafloor sediments act like time capsules and allow us to reconstruct the history of the region, from its past as a wide coastal plain to the development of the modern Great Barrier Reef, and connect this with the cultural stories of the Darumbal people and their close neighbours the Woppaburra people,” Professor Bostock said.
Weaving Modern Science With Traditional Knowledge Systems
The expedition integrated marine geological mapping with the cultural heritage of the region’s Traditional Owners.
Land and Sea Country Rangers from both the Darumbal and Woppaburra communities participated directly in the voyage. Nataliah Backo, a Land and Sea Country Ranger from the Darumbal people, said: We hope this journey makes our families, ancestors, and the Darumbal people proud, while creating stronger pathways for our younger generations to continue caring for and protecting our Land and Sea Country.
Being surrounded by such beautiful people, sharing knowledge and learning from one another has made this experience a very special and memorable one for me. I feel truly blessed to have had this opportunity to learn about the different aspects involved in mapping and understanding the evolution of Sea Country. Tshinta
Ocean Dynamics and Future Reef Protection
Beyond mapping prehistoric topography, the voyage examined the ocean dynamics of the region, paying close attention to how the powerful East Australian Current interacts with the reef’s seafloor, influencing the movement of water and the conditions that sustain life on the reef. Data gathered during the expedition feeds into CSIRO’s eReefs model, a tool used to understand past and present ocean conditions and project how future changes – inducing the intensifying marine heatwaves that have driven mass bleaching events on the Great Barrier Reef – might reshape the ecosystem.
Marine park managers and researchers intend to use these predictive models to identify potential refugia; areas of the reef that may be shielded from the worst impacts of rising temperatures, offering a lifeline for a species with nowhere else to go. Analysis of the sediment cores and oceanographic data will continue over coming months. The findings will be shared with Traditional Owners and marine park managers, contributing to current knowledge gaps. “By weaving together modern science and traditional knowledge systems, we have a much greater understanding of the story of the southern Great Barrier Reef, which will help us better protect its incredible natural and cultural values into the future,” said Professor Bostock.
Продолжение темы
