Today, Antarctica is covered in ice, but during previous ice ages, the ice grew even thicker. Biologists have long been baffled by the question of how and where life has survived over time on the icy continent’s land.
The persistence of life in this inhospitable environment has remained a mystery ever since the first expeditions to Antarctica. Up to this point.
We gathered data to test our theory of how life survived previous ice ages, which was published in Biology Letters. We contend that many ice-free regions, or nunataks, that were not buried by advancing glaciers served as refugia for invertebrates, vertebrates, and plants, allowing them to persist.
Then, as Antarctica gradually warmed up again, these nunatak refuges saw an increase in life and began to repopulate larger areas without ice. The uneven distribution of Antarctic terrestrial life is explained by our method, which also identifies new research priorities to test our theory further.
The coming ice age Many people associate the term “Ice Age” with the animated adventures of Manny, Sid, and Diego (and don’t forget Scrat, the squirrel-rat!). trying to get away from the moving ice.
This story might be true in part. In the Northern Hemisphere, the concept of a mammoth, sloth, sabretooth tiger, and annoying humans migrating south in search of warmer climates is becoming increasingly popular. Additionally, ice-free refuges in southern Europe may have preserved early humans from the last ice age, according to research published this month.
However, land-loving organisms had nowhere else to go in Antarctica. So it appeared up until this point.
Scientists began to think about the possibility of living in ice-free refuges as they learned more about life in Antarctica. However, there was an issue. The expanding ice would have annihilated any land in coastal areas where life still exists that did not have ice. Therefore, how did life endure?
Strange without ice shelters
Utilizing proof from the science and geography of Antarctica, we portray how ice asylums (nunataks) might have given relief to waterfront species.
The movie Ice Age’s clips include: A mismatched trio of prehistoric animals, Manny the woolly mammoth, Diego the sabre-too thed tiger, and Sid the giant sloth, discover an abandoned human infant and decide to return it as the ice age draws near.
Previous studies that suggested geothermal sites provided sufficient ice-free coastal refuges were discounted. This is due to the fact that, in comparison to a 100,000-year ice age, these would have been brief and insufficient to account for the continent’s current existence.
The first evidence-based hypothesis for the existence of life on Antarctica’s continental shelf for millions of years is presented by us. Furthermore, we accomplished this by utilizing the most notable of every single Antarctic invertebrate, a little animal that occupies land without ice all year: springtails.
Springtails play a significant role in global soil health. During early expeditions to the Antarctic Peninsula and the northern coast of Victoria Land from 1897 to 1900, they were among the first animals collected.
From these initial discoveries more than a century ago to the present, we have compiled a database of distribution records for Antarctic springtails.
Additionally, we utilized a previously untapped resource to investigate these survival concerns. By looking at Antarctica’s Informal Cosmogenic-nuclide Exposure-Age Database (ICE-D), we were able to show that ice-free conditions remained at many locations throughout the most recent and previous ice ages.
Cosmogenic-nuclide dating is usually used to find out when a rock was last covered in ice in order to learn more about how ice sheets respond to climate change. However, up until this point, it had not been used to locate ice-free glacial refuges.
We demonstrate that during earlier ice ages, some of these ice-free refuges remained above the expanding ice. Some contained all of a region’s species.
However, how did life repopulate habitats like coastal areas from these refuges? The fact that life in ice-free ecosystems close to glacial margins shifts as the ice expands or contracts provides clues to this remarkable survival story from well-known alpine and polar studies.
Learning lessons for life
The future of Antarctic life is uncertain due to climate change. Extreme events like the catastrophic disintegration of ice shelves, the highest air temperature ever recorded in Antarctica, and the smallest amount of sea ice ever recorded are taking place in the region. It would appear that we are currently in the sequel, “Ice Age: The Crisis.” We hope our performance matches that of Manny and his friends.
A “mammoth” global collective effort to rapidly reduce greenhouse gas emissions is required to limit Antarctica’s permanent change. This is a huge and unheard-of challenge, but it is necessary for Antarctica’s future. Can life continue after the last ice age?
More information: Mark I. Stevens et al, Location, location, location: survival of Antarctic biota requires the best real estate, Biology Letters (2023). DOI: 10.1098/rsbl.2022.0590