Octopus DNA reveals Antarctic ice sheet closer to collapse than previously thought:

Scientists studying how Antarctica’s ice sheets retreated in ancient times turned to an innovative approach: studying the genes of octopuses that lived in frigid waters.

A new analysis published Thursday in the journal Science finds that geographically isolated populations of eight-limbed sea creatures mated freely about 125,000 years ago, suggesting the existence of ice-free corridors during a time when global temperatures were similar to today.

The findings suggest the West Antarctic Ice Sheet (WAIS) is closer to collapse than previously thought and sea levels will face long-term rises if the world fails to keep human-caused temperature rise above the 1.5 degrees Celsius target set by the Paris Agreement. 3.3 -5 meter threat. The author said he agreed.

Lead author Sally Liu of Australia’s James Cook University told AFP that as an evolutionary biologist specializing in marine invertebrates, “I understand and apply DNA and biology as a proxy for past changes in Antarctica.”

She said the Tequita octopus is an ideal candidate to study WAIS because the species is found across the continent and basic information about it is already answered scientifically, such as its 12-year lifespan and the fact that it emerges in about four years . Thousands of years ago.

About half a foot (15 centimeters) long, excluding arms, and weighing about 1.3 pounds (600 grams), they lay relatively few, but large, eggs on the seafloor. This means parents must put in a huge amount of effort to ensure their offspring hatch – a lifestyle that prevents them from getting too far.

In some modern habitats, they are also restricted by circular ocean currents, or gyres.

By sequencing the genomic DNA of 96 samples, often collected inadvertently as fishery by-catch, Lau and colleagues found evidence of the Trans-Antarctic Passage that once connected Weddel, Amundsen and Ross. It then remained in museum storage for 33 years. sea ​​area.

The history of genetic mixing suggests that WAIS collapsed at two different points in time—the first in the mid-Pliocene epoch, 3-3.5 million years ago, which scientists had become confident about; and the last in what is known as The period of the last interglacial, a warm period from 129,000 to 116,000 years ago.

“This is the last time the earth will be about 1.5 degrees warmer than pre-industrial levels,” Liu said. So far, human activities, mainly the burning of fossil fuels, have increased global temperatures by 1.2 degrees Celsius compared with the late 1700s.

“The tipping point for future WAIS collapse is approaching”

Prior to the publication of the new Science paper, some studies also suggested that WAIS collapsed at some point in the past, but these studies were far from conclusive due to the relatively low resolution of the genetic and geological data.

“This study provides empirical evidence that WAIS collapses when global mean temperatures are similar to today, suggesting that the tipping point for future WAIS collapse is approaching,” the authors write.

A rise of 3.3 meters in sea levels would completely change the map of the world as we know it, flooding low-lying coastal areas everywhere.

Writing in an accompanying commentary article, Andrea Dutton of the University of Wisconsin-Madison and Robert DeConto of the University of Massachusetts, Amherst described the new study as “groundbreaking,” adding Said it raises interesting questions about whether ancient history could repeat itself.

However, they note that several key questions remain unanswered, such as whether past ice sheet collapse was caused solely by rising temperatures or whether other variables, such as changes in ocean currents and the complex interactions between ice and the solid Earth, are also at play effect.

It’s unclear whether sea level rise will continue for thousands of years or whether there will be a more rapid jump.

But uncertainty like this is no excuse for not taking action climate change “The latest evidence of octopus DNA adds yet another card to an already unstable house of cards,” they wrote.

Latest news on Antarctic ice

The study comes after scientists confirmed The world’s largest iceberg On Friday, it was “moving” after being trapped on the ocean floor for 37 years. The British Antarctic Survey said that recent satellite images show that the iceberg named A23a is currently crossing the northern tip of the Antarctic Peninsula and moving towards the Southern Ocean.

Earlier this month, the survey was released dramatic video Photos taken by the crew, including drone footage, show a pod of orcas swimming next to a massive iceberg.

The weight of the iceberg is Nearly 1 megatonaccording to data from the European Space Agency (ESA).

The iceberg, which measures nearly 4,000 square kilometers (or 1,500 square miles), broke off from the Antarctic coastline in 1986 but later ran aground in the Weddell Sea, according to the BBC.

Meanwhile, in October, scientists revealed they had discovered a vast, hidden landscape of hills and valleys carved by ancient rivers. “Time is frozen” It has existed under the Antarctic ice for millions of years.

“This is an undiscovered landscape – no one has ever seen it,” study lead author Stuart Jamieson, a glaciologist at Durham University in the UK, told AFP.

The land beneath the East Antarctic ice sheet is less well known than the surface of Mars, Jamison said.

The area covers 32,000 square kilometers (12,000 square miles) and was once home to trees, forests and animals.

But then the ice showed up and it “frozen in time,” Jamison said.