Octopus DNA Reveals Antarctic Ice Sheet Collapse

The study conducted by researchers from various disciplines has discovered that the West Antarctic Ice Sheet likely collapsed during the last interglacial period, around 125,000 years ago. This conclusion was drawn from the analysis of the DNA of a small Antarctic octopus, Turquet’s octopus (Pareledone turqueti).

The researchers compared the DNA patterns in Turquet octopus genomes from different regions around Antarctica. They found direct and unique connections between octopus populations in the Weddell, Amundsen, and Ross seas. These connections could not be statistically explained by interbreeding around the present-day Antarctic coastline. The only way these populations could have come into contact was through seaways that are now blocked by the West Antarctic Ice Sheet.

Furthermore, the researchers found that the most recent DNA signatures of direct connections between these octopus populations occurred during the mid-Pliocene, 3 million to 3.6 million years ago, when temperatures were 2-3°C hotter and sea levels were 25 meters higher than today. This supports existing geological evidence that the West Antarctic Ice Sheet collapsed during that era.

This discovery has significant implications for understanding the potential consequences of global warming. The researchers’ findings provide the first empirical evidence that the West Antarctic Ice Sheet could begin to collapse if we exceed the Paris Agreement goal of limiting warming to 1.5°C or even 2°C.

The study demonstrates the potential of using animal DNA as a proxy for changes in ice sheets and highlights the importance of interdisciplinary collaboration in addressing complex scientific questions. The researchers emphasize the need to use similar approaches to understand other parts of Antarctica with poorly understood climate histories and to explore other biological archives that may provide valuable insights into the past and future of the Earth’s climate.