Beneath the waves of South Australia's southeast, a treasure trove of prehistory awaits discovery. This is the story of how scientists are hoping to unlock the secrets of our past by studying bones found in underwater caves, offering a unique glimpse into the ancient ecosystems of the continent. This article delves into the fascinating research conducted by Griffith University, shedding light on the challenges and potential of this innovative approach to paleontology.
A Glimpse Back in Time
The research team, led by PhD candidate Meg Walker, embarked on an expedition to Mount Gambier, an area renowned for its underwater caves and sinkholes. Their mission: to explore the Fossil Cave and Gouldens Sinkhole, seeking animal bones that could provide insights into Australia's prehistory. The findings were remarkable, with bones dating back as far as the 1840s, including species like cows, kangaroos, emus, sheep, pigs, dingoes, rabbits, possums, and even quolls, a species thought to be extinct in the region for over a century.
What makes this discovery even more intriguing is the unique preservation of the bones in underwater caves. Unlike their land-based counterparts, which are exposed to weathering and land-based bacteria, bones in underwater environments remain pristine. As Walker explains, "In the dry areas, bones are more susceptible to weathering and land-based bacteria, which can decompose them. But in underwater caves, the lack of these environmental factors results in a time capsule-like preservation."
The Science Behind the Dive
The research team, including Walker and her supervisor, Professor Julien Louys, are not just cave divers; they are experts in their field. They have collaborated with the Cave Divers Association of Australia to ensure the safe and ethical recovery of these ancient bones. Advanced diver Joseph Monks has been instrumental in organizing logistics and recruiting divers for these challenging missions. Together, they have uncovered thylacoleo teeth and remnants of ancient dens, providing valuable insights into the past.
However, the decision to recover bones is not taken lightly. Monks emphasizes the importance of responsible exploration, stating, "We have to consider the impact of our actions on these ancient caves, which are thousands of years old. Moving and touching the bones can leave a lasting change, so we must carefully assess the value of each discovery for the science it contributes."
Filling in the Record
While the bones studied in this research primarily date back to the past 100 to 200 years, the potential of underwater caves to reveal Australia's prehistory is immense. Walker highlights the limitations of land-based fossil records, stating, "We have the World Heritage Naracoorte Caves nearby, which offer a wealth of information, but preservation is limited. We don't have a continuous record of species changes over time."
Underwater caves, she argues, can provide a more comprehensive understanding of past ecosystems. "By studying these caves, we can piece together the different aspects of the cave's history, including the presence of new species and changes in species over time. This could help us address extinctions and gain a deeper understanding of Australia's natural history."
Leading the Way
The work being done in South Australia is setting a precedent for paleontological research worldwide. Monks believes that the region's cave systems, combined with their pristine state and accessibility, make it an ideal location for such studies. "We are at the tip of the iceberg," he says, emphasizing the vast potential for discovery. As the team continues to explore these underwater time capsules, we can expect to uncover more fascinating insights into Australia's prehistory, offering a unique perspective on our past that was once thought to be lost forever.
