Octopus DNA analysis by Australian and New Zealand scientists suggests that an Antarctic ice sheet collapsed around 120,000 years ago under conditions similar to today. The study focused on Turquet's octopus in the Southern Ocean, revealing genetic connectivity to the last interglacial period – 130,000-115,000 years ago – marked by warmer climates, higher sea levels and smaller ice sheets.
According to the study, published in the journal Science on Thursday, the finding helps answer the long-debated question of whether the West Antarctic Ice Sheet (WAIS) collapsed during that period.
"This genetic connectivity would only be possible if a complete collapse of the WAIS occurred during the Last Interglacial, opening seaways linking the present-day Weddell, Amundsen and Ross seas," study lead Jan Strugnell from Australia's James Cook University said in a Friday statement.
"This would have allowed octopus to travel across the opened straits and exchange genetic material, which we can see in the DNA of today's populations," said postdoctoral research fellow Sally Lau.
Strugnell said the last interglacial period was when "global average temperatures were 0.5-1.5 (degrees Celsius) warmer than preindustrial levels and global sea level was 5-10 meters (16.41-32.81 feet) higher than today."
"What makes the WAIS important is that it's also Antarctica's current biggest contributor to global sea level rise. A complete collapse could raise global sea levels by somewhere between 3 and 5 meters," she said.
"Understanding how the WAIS was configured in the recent past when global temperatures were similar to today, will help us improve future global sea level rise projections," Strugnell continued.
