Underwater 'time capsules' hold the key to Australia's prehistory, according to a team of researchers led by Griffith University. The study, published in a new paper, focuses on the unique preservation of fossils found in underwater caves, offering a glimpse into the past that could revolutionize our understanding of the continent's history.
PhD candidate and lead author, Meg Walker, emphasizes the limited knowledge surrounding fossils in these cave systems. By studying the impact of the underwater environment on bone preservation, the team aims to develop tools that will enable scientists to decipher the age and context of these ancient remains.
One of the most intriguing aspects of this research is the potential to link fossils to specific periods of dryness or wetness. Walker suggests that this could help reconstruct the ecosystems of the past, revealing how animals and their habitats evolved over time.
The team's expedition to Mount Gambier in South Australia's southeast provided valuable insights. They explored Green Waterhole, known to divers as Fossil Cave, and Gouldens Sinkhole, uncovering animal bones dating back to the 1840s. The diversity of species found, including cows, kangaroos, emus, sheep, pigs, dingoes, rabbits, possums, and quolls, highlights the ecological changes that have occurred in the region.
What sets underwater caves apart is their ability to preserve bones in a pristine state, almost like a time capsule. In dry areas, bones are more susceptible to weathering and land-based bacteria, but underwater environments protect them from these processes. As Walker explains, "As you go further into the cave, you don't even have the aquatic bacteria anymore. [The bones] are just absolutely pristine."
The research team, including cave divers and scientists, has been working closely with the Cave Divers Association of Australia. Advanced diver Joseph Monks has been instrumental in organizing logistics and recruiting divers for the missions. Together, they have discovered thylacoleo teeth and remnants of ancient dens, revealing the richness of the cave system.
Despite the challenges of working with ancient caves, the team is committed to making informed decisions about which bones to recover. Monks emphasizes the importance of preserving the integrity of the caves, stating, "For us to move and touch stuff, we're making a change that's going to last the life of that cave."
The study's findings have significant implications for paleoenvironmental research. While the bones in this study date back only 100 to 200 years, Walker believes that fossils found in underwater caves can fill knowledge gaps and provide a continuous record of species and ecological changes over time.
The team's work in South Australia is considered groundbreaking, with Monks stating, "The cave system there and how pristine it is and the access just leads the way for this to happen. We're at the tip of the iceberg."
As the research continues, the potential for uncovering new species and understanding past extinctions becomes increasingly exciting. Walker concludes, "Hopefully after we do that we can use it as a foundation to understand species through time, changes to species over time, and potentially address different extinctions."
This research not only contributes to our understanding of Australia's prehistory but also highlights the importance of preserving and studying underwater cave systems, which could offer a wealth of information about the Earth's past.
