Lake Mercer, a subglacial lake far below the Antarctic Ice, has remained untouched for thousands of years – until now.
Scientists accidentally discovered the lake in 2007, when they examined satellite imagery of the Antarctic ice sheet. Then on December 26, 2018, they finally reached it.
To explore subglacial lakes as deep as 50 feet, researchers from a project called SALSA (Subglacial Antarctic Lakes Scientific Access) had to make a small hole almost 1 kilometer into the ice. They did this using a drill with a pencil-sized nozzle that sprayed hot water. After the hole is made, they then use a corer to pull the sample back to the surface.
The team anticipated finding microbial living things in the sample – and they did it – but they were surprised by what else was hiding in the mud. The sample also contains small crustaceans (smaller creatures from poppy seeds) and tardigrade bodies, an eight-legged invertebrate known for its ability to survive in the harshest conditions.
Surprise in the mud
The SALSA team finally extracted a 5.5-foot (longest from subglacial lake) core along with "six of the six sediment cores that were perfectly & # 39 ;." They also filled six 10-liter bottles with lake water and caught the first record of the lake. Their work was transported back to McMurdo Ice Station for analysis, according to the SALSA project blog.
When the researchers found the bodies of small crustaceans and tardigrades in the sample, Priscu was so shocked that he thought the findings were a mistake. He believes that the core has been contaminated, reports Nature. So he asked the team to clean their equipment thoroughly and take more samples.
When the new sample returns, there it is: more crustacean shells. Nothing like this has ever been found under the previous ice sheet.
Lake Mercer is the second sub-glacial lake that scientists have accessed – they also drilled 2,600 feet down to reach the nearest Lake Whillans in 2013, but the samples taken there showed no signs of higher life forms (only microbes).
Microbial life is most likely in this mud under ice because the oceans covered the area about a million years ago, the SALSA chief scientist, John Priscu, told Axios. But that does not explain the origin of the carcass.
Instead, this discovery shows that these crustaceans and tardigrades once lived on the continent; somehow, they were transported to the lake from the nearest mountains (where such creatures were found before). Moving water can carry them, or the glacier might have dragged it up, according to Nature.
How to reach the lake under the ice
Subglacial Antarctica is part of a water channel.
Streams and rivers connect hundreds of bodies of water under the ice, and this network has changed during Antarctic history. Understanding how the continent's ice responds to climate change Earth helps scientists understand more about its history.
"Antarctica is a place on Earth that is rarely touched by humans, and is therefore an extraordinary laboratory for understanding life and biodiversity, and the history of our planetary glaciers," Ross Virginia, director of the Dartmouth College Arctic Study Institute, told Business Insider.
In addition, studying Antarctic waterways is an important way to monitor the potential consequences of global warming.
"The evolution of the ice sheet and the ice sheet are the main drivers of sea level rise," Virginia said.
But researching the Antarctic subglacial system is very difficult.
Virginia has worked and died in the Antarctic Dry Valley for almost 30 years, and has worked with Priscu on other Antarctic research projects. Drilling in this environment, he said, requires the same treatment as NASA did when exploring a new world in space – "such as quarantining astronauts returning from the moon or maintaining sterile equipment."
This is because contamination can easily damage expensive and important research, or even make scientists think that they have found the real type of life that is not there.
"We are always worried about contamination," Victoria said. "You don't want to introduce surface organisms to locked subsurface ecosystems."
That's why good equipment is very important.
The SALSA team uses a corer – which is basically a tube screwed to the ice – from the Woods Hole Oceanographic Institute. Although the holes they drilled were not more than 60 centimeters, the researchers were able to shift the corer to a channel nearly 1 kilometer long. After hitting the sediments below, the corer – and the lake mud it takes – is pulled back to the surface.
Pave the way for drilling in other extreme environments
Because drilling operations are very difficult and complicated, the SALSA project can offer lessons to pursue research in other extreme environments, maybe even those on other planets.
Drilling in Antarctica is as close as scientists can understand to what is needed to drill into the liquid ocean of Jupiter Europa, Mark Skidmore, a professor of earth science at Montana State University told Axios.
Experts think the European oceans are one of the most likely places to find extraterrestrial life in our solar system.
"We learn about the types of technology and processes and how you will do it, and learn about what you will find in that type of environment," Skidmore told Axios.
But drilling below Antarctica also benefits us on Earth
Virginia's biggest concern is that the huge floating ice that extends from the Antarctic continent melts from below thanks to warm water. (Last year was the warmest year ever recorded for the Earth's ocean.)
When the ice sheet melts from below, they lose structural integrity. If they are destroyed, that could mean continental ice waves will flow into the ocean – an event called the "pulse" that will contribute to rapid sea level rise.
"The sheets act like dams," Virginia said.
On the one hand, Antarctica responds to climate change and provides control over the Earth's climate, he said: "The history of the Antarctic climate is connected to the world."