Photo by Pia B
Published on: Dec 28, 2023
A groundbreaking study using octopus DNA has provided pivotal clues about the history of the West Antarctic ice sheet's collapse, offering insights crucial for understanding future sea level rise. Researchers at James Cook University in Australia conducted this innovative study, focusing on the genetic history of the Turquet’s octopus (Pareledone turqueti), a species native to the Antarctic seafloor.
The study, published in the journal Science, employed DNA sequencing of 96 Turquet’s octopuses, gathered from various global institutions and fishing bycatch. These samples, dating back to the 1990s, offered a genetic timeline extending millions of years into the past. This 'genetic time capsule' allowed the researchers to trace interactions among different octopus populations and pinpoint the timing of the last ice sheet collapse.
The findings suggest that the most recent collapse of the West Antarctic ice sheet occurred over 100,000 years ago, during the Last Interglacial period. This period witnessed global temperatures akin to present-day levels. The collapse would have inundated coastal regions and opened new areas on the seafloor, facilitating breeding among previously separated octopus populations.
The study's lead author, Sally Lau, emphasized the significance of DNA as a historical record, providing unprecedented insights into past climatic events. This approach revealed genetic connectivity between different octopus populations around 125,000 years ago, implying the ice sheet's collapse at that time.
This research is pivotal as it sheds light on the West Antarctic ice sheet (WAIS), a significant contributor to global sea level rise. "Understanding how the WAIS was configured when global temperatures were similar to today will help improve future sea level rise projections," stated Jan Strugnell, a key contributor to the study.
The choice of Turquet’s octopus for this research was strategic. Their limited mobility and tendency to breed within local populations made them ideal candidates for studying historical genetic patterns. Furthermore, their well-understood biology and DNA mutation rates enabled accurate molecular dating.
The implications of this study are profound, offering a new perspective on climate history and helping predict future climatic shifts. With this innovative approach, researchers can continue to explore other Antarctic regions with unresolved climatic histories, enhancing our understanding of Earth's environmental changes.