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"It was like landing on another planet." This is how several members of an Antarctic expedition describe the moment when their cameras showed for the first time the bottom of Lake Mercer, the deepest that was explored in detail on this continent. Under the Antarctic ice, there are more than 300 lakes – many of which are connected – which form a more unknown environment than the surface of Mars.
After a decade of preparation, an expedition led by the United States was able to pierce 1,068 meters of ice to reach Mercer's waters. "We believe that this lake and all the organisms that inhabit it have been completely isolated from the outside for at least 100,000 years," says John Priscu, scientific leader of the Scientific Access to Lakes Under Marine expedition. – Antarctic Sea (Salsa)
. These liquid sarcophagi are the closest thing to our planet to the subglacial lakes and oceans of Mars, Pluto or the moons of Jupiter and Saturn, some with more water than the Earth. These are the places most likely to find life in the solar system.
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On November 26, a trailer of bulldozers, tractors and containers on sledges left the North American Antarctic Base at McMurdo to travel 1,046 km into the interior of the continent. A radar vehicle leads the entourage by sending signals underground to detect cracks that could bury vehicles under tons of ice. The caravan includes mobile homes equipped with heating, bunk beds, a dining room and a kitchen where one can even bake bread in the middle of the inhospitable ice desert. It also carries nearly 500 tons of equipment needed to drill ice and badyze the lake. After reaching the lake for the first time in 2017, the excavators began to build a landing strip for the aircraft carrying the rest of the expedition, out of a total of 50 participants, among scientists, drillers, mountaineers and soldiers.
In the early 1960s, Soviet scientists who explored Antarctica exploded explosive charges embedded in the ice to measure the propagation of the shock wave. Thus was discovered Lake Vostok, the largest in Antarctica, buried 3,400 meters under the ice. Since then, Russia, the United States and other countries have launched a race to be the first to reach and badyze the pure water of any of these lakes. Russia claimed to have achieved this goal in 2012, but the samples could be contaminated and invalid. The Mercer, discovered ten years ago by satellite imagery, is "the deepest that has been reached without contaminating the waters and has been explored in detail," says Priscu, back at McMurdo Station
Mercer Lake has a surface area greater than that of Barcelona and a depth of 15 meters. The mission reached its waters on December 27, 2018, after melting about 28 tons of ice with a drill that spewed sterile hot water. During the first days of 2019, 60 liters of water and five meters of sediment columns were removed from the lake bottom, which, when they reached the surface, "bubbled unidentified gas." "says Priscu. The lake is at half a degree below zero, but the pressure inside is about 100 times that of the surface, allowing the water to remain liquid and in contact with the mud and the rocks in the background, a favorable environment
The first badysis shows that every milliliter of lake water contains about 10,000 microbes, several orders of magnitude less than in the world. ocean, but something considerable at a place where no ray of light arrives. "The lake contains little oxygen relative to the air, which is due to the metabolism of these microbes," says Priscu.
The team explored the lake with a robot capable of taking pictures, collect stones with a small arm. "The lake water is like skimmed milk, very cloudy, we could only see what was less than 25 centimeters from the cameras," says Bob Zook, Nebraska University engineer and creator of the robot. "It was like a landing on the moon," he says.
the team hopes to badyze the DNA samples, which will determine if there are animals other than microbes inside the lake. The team will also try to create Antarctic microbes in the laboratory. "Our data will be used to design experiments capable of studying the oceans of the outermost regions of the solar system and to determine if there is a second origin of life," Priscu said.
"It's a science dream.Every day is a treat and every meal is a treat," says this microbiologist from the University of Montana. Someone drank Mercer's water? "We were tempted, but the samples are too valuable," he says.
The first images of the bottom of Lake Mercer Subglacial! At 3,500 meters under the ice, it's one of the most difficult places to reach on Earth. #nsfSALSA IP Kathy Kasic and graduate student Billy Collins outfitted a @GoPro Benthic 2 housing in deep water for immunization. Antarctica is home to 90% of the Earth's ice and 70% of the fresh water, while Antarctica is home to 90% of the ice and 70% of the fresh water. The melting of the continent has tripled in three decades. If it melted completely, the sea level would rise by 60 meters, enough to cover an area of land greater than that of the European Union as a whole.
It is essential to understand the hydrological system hidden under the ice of the continent to predict the effects of climate change. The shipment, worth US $ 5.2 million (about US $ 19.5 million), used techniques to minimize the inflow of water out of the lake and ultraviolet radiation for eliminate surface microbes Drilling equipment. It is the second lake to which the team accessed after reaching the nearby town of Whilans in 2013, where it also found abundant microbial life.
The water of Vostok is renewed at times scales of tens of thousands of years. at Mercer, this happens in the order of several decades. This second lake receives two streams of fresh water, the largest of them coming from the west of the mainland and the one from the east. It is thought that the lake flows into the Ross Sea south of the continent and is therefore a key element in understanding how the unknown and invisible network of lakes under Antarctic ice contributes to the equilibrium of the waters in the oceans. This type of expedition "changes our conception of the fifth continent, we can not continue to see it as a huge block of harmless ice, but instead we see that under the ice is the largest wetland on the planet. which plays a global role, "said Priscu
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