The Lost World of Lake Vostok (2000) BBC Horizon

The Lost World of Lake Vostok

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NARRATOR (DILLY BARLOW): It sometimes feels as if every corner of our planet has been explored, but Earth still has one secret left, locked away in the heart of the great Antarctic wilderness. These men are walking on top of 4 vertical kilometres of ice, but it’s what is underneath this ice that has turned this remote part of Antarctica into one of the hottest pieces of scientific real estate in the world, for beneath their feet lies a vast, mysterious lake. No-one has ever seen it and for a long time, no-one even knew it existed.

PROF. JOHN PRISCU (Montana State University): Lake Vostok is so exciting to scientists because it’s the last unexplored frontier on our planet.

DR FRANK CARSEY (NASA Jet Propulsion Laboratory): This is a very large, dark, cold body of water that has been doing its own thing for at least 3 million years, possibly 30 million years.

DR. ROBIN BELL (Columbia University): It’s just such an extreme place. There’s almost nowhere on the Earth left that we know so little about.

NARRATOR: But the most enticing prospect of all is what scientists might find living down there. This unvisited frontier could help explain how life began on Earth. It may even hold the key to finding life on other planets. 50 years ago no-one believed that water could remain liquid in the freezing conditions of Antarctica’s ice sheet. It seemed to defy the laws of physics but then the Russians built a scientific base in the middle of this hostile land and it was here that conventional wisdom was overturned. Vostok Station was established in 1957 in the coldest place on Earth. It was so remote that to supply it required an epic 1,000 kilometre tractor journey from the coast through some of the harshest conditions on the planet. One of the Russian scientific aims was to measure the thickness of the ice sheet. It was a task taken on by a young geographer, Andrei Kapitsa, but for him, like everyone else in this intrepid team, science took second place to survival.

PROF. ANDREI KAPITSA (Moscow State University): The best way to warm yourself up you eat butter. A pound of butter goes in you and suddenly you are warm again and everything is nice and it's like drinking a glass of vodka but much better.

NARRATOR: Andrei Kapitsa suggested that the frozen Antarctic wastes could be hiding a great secret. Flying over the Vostok area he noticed that the ice seemed unnaturally flat. The only explanation he could come up with was almost unthinkable.

ANDREI KAPITSA: You saw a very flat plain which we understood could be water underneath and the middle of Antarctica could be a lake.

NARRATOR: Kapitsa believed that if the ice was thick enough it could act like an insulating blanket preventing the Earth’s heat from escaping. In theory, this trapped heat might melt the bottom of the ice sheet and over time water could gather into a lake. If Kapitsa was right there could be a secret world buried beneath the ice, a place that no human had ever seen but most people thought the idea was ludicrous. They believed a lake would freeze solid underneath the Antarctic ice sheet.

ANDREI KAPITSA: Nobody would believe me, that is the tragedy of new ideas. They are never believed at the beginning.

NARRATOR: Kapitsa needed proof. Using explosions he sent sound waves down through the ice. Each time they hit a different substance the waves reflected back to the surface. In theory if a lake was present it would show up as two distinctive reflections, one from the surface of the lake and one from the bottom. When Kapitsa looked at the data from his explosions he discovered that the ice sheet was an extraordinary 4 kilometres deep, thicker than anyone had believed, but he saw no lake. Eventually Kapitsa went home to Moscow and never visited Antarctica again. It wasn’t until the 1970s that a British team brought the idea back to life. They were using a sophisticated new technique - airborne radar – which could reveal the mountainous landscape beneath the ice sheet, something that had never been seen before. With each flight the mountains stretched on further. Then on Christmas Day 1974 north of the Vostok Station they discovered this. It seemed they could only be flying over water, but despite the radar evidence the full picture of what lay beneath the ice wasn’t fully understood until just a few years ago. Satellites orbiting Antarctica revealed what it had been impossible to see from Earth: the true scale of the discovery at Vostok – an enormous lake. It was half the size of Wales. Hidden beneath Vostok Station buried by 4 kilometres of ice was a lake over 500 metres deep. One of the biggest lakes in the world. The massive ceiling of ice would create a place of absolute dark and intense cold, crushed by immense pressure, a strange and hostile other world here on Earth. It was a stunning discovery.


DR CYNAN ELLIS-EVANS (British Antarctic Survey): Amazing.

ROBIN BELL: Really exciting.

NARRATOR: Scientists were tantalised. They desperately wanted to study the lake, but they had no way of getting down into it, but for geologists the very existence of the lake was intriguing. Robin Bell has spent her career studying Antarctic geology.

ROBIN BELL: The thing that is driving the scientists to actually understand how this whole lake is existing and what’s going on inside it. The geologic setting for Lake Vostok is something we don’t find anywhere else right now on Earth.

NARRATOR: If geologists could work out how this unique lake formed it would help scientists understand what, if anything might be living down there. If the lake did form when the ice melted under its insulating blanket it would never have had any contact with the outside world. The prospects for life would be bleak, but now there’s a new theory. The lake may have formed before the ice came and covered it. If this is right it increases the chances for life. The first clue came from its shape.

ROBIN BELL: The lake is long and skinny. It’s very similar to other long, skinny lakes on Earth. Here’s a satellite image for Lake Vostok. If we compare it to other lakes in the Earth and look how those lakes are formed. Here’s Lake Malawi, it’s in Central Africa. This is in a part of Africa that’s being actively pulled apart. When the Earth pulls apart it breaks, there are faults along the edge of this lake and so by comparing the shapes we can say that Vostok is probably a rift.

NARRATOR: Some geologists theorised that the Earth beneath Vostok could have been pulled in different directions by these forces until it split open, but it was when Robin Bell looked at the timing of this process that she realised how old the lake could really be. ROBIN BELL: My evidence for the timing is based on estimates of how long it takes to form other rift lakes like that. I think the lake formed in the last 30 million years.

NARRATOR: 30 million years ago the whole world was much warmer and Antarctica was temperate, so if Robin Bell’s timing are correct rain would soon start collecting in the rift and the lake that formed would have been teeming with life. There could have been everything from insects to fish. What happened next would have been cataclysmic.

ROBIN BELL: The world got really cold 15 million years ago and then we know that Vostok sits right next to the biggest highland in east Antarctica. There are big mountains, Vostok sits right here, that ice sheet would have started forming on top of the mountains and covered Lake Vostok very quickly.

NARRATOR: So 15 million years ago, well before the human race had evolved, Lake Vostok would have begun to disappear beneath the ice. As the ice built up it would have buried the lake cutting it off from the rest of the world completely. Under the thickening roof of ice the pressure would have mounted and the waters would have got darker and darker.

CYNAN ELLIS-EVANS: Lake Vostok is essentially a lost world. It’s been lost for millions and millions of years and has been sitting completely in isolation from all the things that have been happening in the world around it.

NARRATOR: For biologists the challenge is how to study this lost world. They need samples to analyse, but there are no samples from Lake Vostok, so they can only speculate about what happened to the life after the lake iced over.

CYNAN ELLIS-EVANS: The plants would have disappeared very quickly and once the plants went you lost a major source of food supply for the more complex animals, so once, the plants would disappear the, the animals would follow soon after and once they were gone all that would be left in the lake would be the microbial populations and even they would then start to thin down to the organisms that could make the best of the limited resources left.

NARRATOR: So if anything has survived in Lake Vostok it will be microbes. They are the magicians of survival. They have an extraordinary ability to adapt and evolve to any conditions and what’s more, every creature on the planet, including ourselves, evolved from microbes. Biologists hoped that if they could find any microbes that have adapted in isolation in Lake Vostok that it would give them some insight into how life began and evolved on Earth.

CYNAN ELLIS-EVANS: By going back to the microbial history in Lake Vostok we are going to be learning more about how life evolved on this planet. Any microbes we find in there will have had no contact with the outside world and so we’ll be able to look at them in almost like a laboratory setting, that here we have a test-tube that has been closed off for millions of years and kept at a permanently low temperature. What sort of evolution would have happened in that time and what rate of evolution is possible under those circumstances?

NARRATOR: Biologists also think that isolation in this strange environment could have led to the evolution of unique microbes.

JOHN PRISCU: As biologists try to understand the evolution of life on our planet one of our primary goals is to seek and discover habitats that have been isolated from our surroundings for millions of years. The isolation we’ve seen in lake Vostok would, would lead a lot of scientists to believe that there’s a lot of evolutionary distinct forms in the lake.

CYNAN ELLIS-EVANS: We are almost certainly going to turn up organisms which are going to have very curious properties. These are organisms there which, the like of which we may not have seen on this planet before.

JOHN PRISCU: For an Antarctic scientist like myself, polar scientist who’s spent most of his career working in polar regions, this was, this was the Holy Grail.

NARRATOR: If they could only get down into the lake they might find life quite alien to Earth, but while biologists were hoping that something strange might have survived here, the pristine isolation that makes Lake Vostok so special was already under threat. Ironically the threat came from science itself. From a unique project that brings scientists from around the world to the crumbling Russian base that sits directly on top of Lake Vostok. The project is one of the most ambitious climatology studies ever started and it depends on one crucial thing: drilling an ice core. The ice contains information on the Earth’s past climate. The deeper they drilled the further back in time they went, until they had a core over 3½ kilometres long that could tell them how the climate changed over the past half million years. The Russians began drilling these cores 25 years ago, long before they knew lake Vostok was beneath them. When its discovery was announced they realised the drill was tantalisingly close to the lake. If they just went on drilling they could get the one thing scientists were desperate for: a sample of Lake Vostok water, but there was a problem. Drilling is a dirty job. At Vostok they use 65 tons of oil-based kerosene to keep the drill hole open. If the drill entered the lake the purest body of water on Earth would have its first oil slick.

DR JEAN ROBERT PETIT (Vostok Ice Core Project): There is no technical problem to drill down to 4 kilometres even to penetrate the lake, but from a scientific point of view it would be a disaster because the fluid, the kerosene that we used could be mixed with the water and then we will bring some contamination, obvious contamination.

NARRATOR: Not only that, the kerosene would bring a more insidious form of contamination. Because mixed up in the fluid a bacteria from the environment. If these microbes enter the lake then it would be impossible to tell which were the genuine lake microbes and which had been introduced by the drilling fluid.

JEAN ROBERT PETIT: We do not want to penetrate the lake at least with this technology. We should develop another technology, a clean technology, which prevent any contamination for this, for this water.

CYNAN ELLIS-EVANS: Contamination of Lake Vostok would be a disaster. If this is the most pristine system of its kind on the planet, we have an absolute need to preserve this pristine, pristine situation.

NARRATOR: So just over 100 metres above the lake the drill was brought to a grinding halt. For the last 2 years the drills at Vostok Station have been silent. Scientists simply don’t have the technology to drill further without causing irreversible contamination. Meanwhile, a dramatic new discovery was about to make Lake Vostok of enormous importance to space research. The key lay in a series of mysterious images from space. It all began when NASA launched the Galileo probe. Its mission was to send back data from the planet Jupiter and its 12 orbiting moons. Scientists were intrigued by one of these moons in particular – Europa. It was staggeringly bright and they realised it was completely encased in ice. As the pictures came back, scientists searched for clues to tell them what was under the ice on this remote moon. NASA scientist Frank Carsey was one of a team studying these strange pictures.

FRANK CARSEY: The most intriguing images are the ones that are called chaos. Here we have blocks of ice a few kilometres across in this matrix of ice. For me personally this was very significant because I had seen this before. Here is an image taken from the Arctic Ocean on Earth and we see again irregularly shaped blocks of ice in this matrix of smaller blocks of ice and freshly formed ice. These are the consequence of this ice moving around on the Arctic Ocean and if we bounce back and forth a bit between these two you will see that we have here on Europa larger blocks, smaller blocks, exactly the same as we have in this data from Earth.

NARRATOR: Comparing photos of the Arctic Ocean with the surface of Europa the team came to a startling conclusion.

FRANK CARSEY: This was really a crucial point at which we felt we were looking at Europa on ice that was floating on an ocean and this is a very exciting prospect.

NARRATOR: It was the first time scientists had found convincing evidence for the presence of liquid water outside our own planet. Liquid water is the single most important prerequisite for life, so finding an ocean on Europa presented NASA with the extraordinary possibility that Europa could be home to extraterrestrial life. This is what NASA had always dreamt of, but exploring this alien world in search of life seemed an impossible task. NASA had worked out that the ice on Europa is many kilometres thick and developing clean technology to penetrate it would pose a completely new challenge and then they heard about Lake Vostok.

FRANK CARSEY: Timing is everything here. As we were looking at the pictures from Europa and realising the high likelihood that we were looking at a planet with a shell of ice a few kilometres thick sitting on this very deep old ocean, we also began to see results coming back concerning Lake Vostok and Lake Vostok also is a large body of water under several kilometres of ice and I and my colleague realised that we had a capital opportunity here to stage explorations to both of these very exciting places.

NARRATOR: These scientists reasoned that if they could devise technology to explore Lake Vostok without contaminating it, that same technology could then be used on Europa. Not only that, the possibility of finding life in Lake Vostok took on new meaning.

FRANK CARSEY: Life in Lake Vostok can demonstrate to us that that environment is a habitat in which microbes could thrive at Europa.

NARRATOR: Lake Vostok was about to become a step towards discovering life beyond our planet. But there remained one crucial question: even if scientists could explore either Lake Vostok or Europa would they find any life there at all? Both places lacked one crucial ingredient for life – light.

CYNAN ELLIS-EVANS: Lake Vostok is covered by 4 kilometres of ice and therefore not one photon of light can penetrate. Light energy is one of the major drivers, one of the major energy sources on this planet as far as organisms are concerned and it is not going to be present.

NARRATOR: Nearly all the life we know relies on energy from the Sun. At the base of the entire food chain are plants that live by photosynthesis and we all live off them. Even under water light is essential to life. So it would seem that in the light starved world of Lake Vostok nothing could survive, unless of course it has cunningly adapted to a different energy source, but other than light what else could fuel life? A clue came from underneath a rubbish dump in Romania. Here cave scientists stumbled across a biological treasure trove. When these shafts were sunk a cave was discovered 20 metres below the surface, but this was no ordinary cave.

DR SERBAN SARBU (Cave Biologist): We very soon realised that in fact this cave had never had an entrance, a natural entrance, was never opened to the surface and this artificial shaft that we descended was the only possible access into the system.

NARRATOR: It was like a bubble trapped in rock. Until it was broken into nothing from the surface had got into it, perhaps for millions of years. What they had found was a world as dark and isolated as Lake Vostok. To begin with they found nothing out of the ordinary, just a series of cramped tunnels. But when they arrived at a small pool there was a surprise in store for them.

SERBAN SARBU: The first surprise that I experienced was that we found a lot of animals present and when I say animals I think of spiders, centipedes, wood lice.

NARRATOR: But these creatures were unlike anything he’d ever seen before. They were all blind and many of them were almost colourless. In total, Serban found 33 species entirely new to science. It meant that the cave must have been cut off for millions of years to allow the new species to evolve separately, but the surprise didn’t stop there.

SERBAN SARBU: Most of all what was surprising was the fact that they are extremely active. This is really atypical for any other cave creatures. They tend to move usually very slowly, you don’t see them waste a lot of energy. Here in this cave they are moving fast, they are very active, they run all over the place, that there’s an indicator of the fact that there is a lot of energy available to them.

NARRATOR: And yet the cave was completely sealed off from the surface. Nothing could get through, not even rainwater and certainly not light, so where were these creatures getting their energy from? It seemed a mystery. Serban’s only clue was that all the creatures lived close to the pond, so he set off to explore the underwater passages. After a short while he came to a small air bell, a chamber only half filled with water.

SERBAN SARBU: I had to pass through a layer of scum that was floating on the surface of the water. It was really ugly looking yellowish orange colour, we had really no idea what it is.

NARRATOR: Serban thought that the layer of scum must hold the key to the cave’s ecosystem. Eventually he realised that it was made up of microbes. The scum was a thick microbial mat. This was the base of the food chain, but what were the microbes living on? When Serban analysed the microbes, he discovered that in the absence of sunlight they were using hydrogen sulphide as their energy source. The microbes were extracting energy from chemicals in the water. It’s a process known as chemosynthesis The water in the cave is rich in hydrogen sulphide which comes from hot springs welling up from deep within the Earth.

SERBAN SARBU: This is the power source this is the fuel that keeps the underground eco-system going.

NARRATOR: This cave shows that the secret of sustaining life in dark, isolated underwater worlds is hot springs. If there were hot springs in Lake Vostok the odds of finding a more complex range of creatures would soar, but hot springs occur in geologically active areas. Even if Lake Vostok was once an active rift that does not mean it’s still geologically active today. Most scientists believe that East Antarctica is now geologically dead. There are no volcanoes and very few Earthquakes but last year Robin Bell discovered that a few of those Earthquakes formed an intriguing pattern.

ROBIN BELL: There is a line of Earthquakes in East Antarctica where there aren’t very many Earthquakes and I just jokingly said to my friends well look, maybe this is important. Here they are plotted. You can see it’s parallel to the edge of the lake. Earthquakes running here, the lake running here. This suggests that the processes that formed Lake Vostok the pulling apart of the Earth are active today and that there’s a good chance there may be hot springs along the edge of Lake Vostok.

NARRATOR: In the absence of light these hot springs might fuel life in Lake Vostok.

CYNAN ELLIS-EVANS: If we can find the hot springs in the lake it’s going to offer us more possibilities to find a greater range of organisms and that’s going to increase the chances that we’re going to find something really interesting.

NARRATOR: Back at Vostok Station the story of the lake has taken an extraordinary new twist. Quite by chance it turns out that scientists may unwittingly have got their hands on an actual sample of water from the lake. Buried in the ice core they found something completely unexpected. The very bottom of the ice core looked different from all the rest. Mysterious black lumps were embedded in the ice. Scientists were perplexed.

JEAN ROBERT PETIT: We say OK, we are very deep, we reach 3,600 metres, but there is strange ice there. We cannot explain.

NARRATOR: Under polarised light the normal crystal structure of the ice is full of hundreds of tiny crystals, but the bottom layer of ice was very different, just a few huge crystals.

JEAN ROBERT PETIT: The crystal size were pronouncedly(?) bigger. We get one core long like this, one metres long only one crystal and we were very surprised to find such a crystal. I never saw that.

NARRATOR: Those giant crystals meant that the bottom layer of the ice core couldn’t be from the ice sheet above the lake. That left only one source for the ice: Lake Vostok itself. Lake water must have frozen onto the bottom of the ice sheet over thousands of years. The black lumps must once have been sediment floating in the lake that was trapped when the ice formed.

JEAN ROBERT PETIT: Vostok. I’m holding in my hand this piece of ice which come from the incredible Lake Vostok and it is a, a clear sample of the water from this incredible lake.

NARRATOR: A sample of the ice was sent to Antarctic biologist John Priscu for analysis. He prepared his samples meticulously. He was hoping to find some sign of life in the sample, the first proof that life existed in Lake Vostok. It looked as if the lake could be about to reveal its secrets and under the electron microscope this is what he saw. Not just one, but hundreds of tiny white microbes.

JOHN PRISCU: When we found the microbes I had the $100 bill out to light the cigars, you know. This the first evidence for life at like 4 kilometres below the surface of the ice. The lake the size of Lake Ontario. This is quite a, quite a find.

NARRATOR: It seemed a triumph, but then doubts crept in.

CYNAN ELLIS-EVANS: The bugs that are being reported from the ice by John Priscu are potentially real, but they also there is the potential from them being contaminants because the drilling fluid around the ice core would have been contaminated with microbes. We know that and we do know that micro-cracks are formed during the stresses of drilling and microbes could potentially move through these micro-cracks into the centre of the core and contaminate the clean centre. I think that the, the jury is still out as to whether the discovery of bugs in the ice is a real result or contamination. The only way we’re going to really satisfy that question is to actually go into the lake itself.

NARRATOR: NASA hold the key to getting down into the lake. They remain determined to search for life on distant Europa, so they’ve turned their formidable resources to the task of working out how to get into its surrogate, Lake Vostok, to find life before they fly to Europa. NASA will have to design a remote controlled robot that can hunt for life in a vast expanse of water. It will be like looking for a needle in a haystack and because this robot won’t be able to bring samples back to the surface, it will have to carry on board a raft of devices that will help its search for life. Ken Nealson runs a team of NASA scientists who develop technology to hunt for life in extreme environments. They regularly come to Mono Lake in California to practice. It’s rather more accessible than Lake Vostok, but shares an important characteristic.

PROF. KEN NEALSON (NASA Astrobiology Group): If one thinks about Mono Lake and Lake Vostok they certainly don’t look similar or feel similar, but they have some uniting features of both being hostile environments that may harbour life that we’re not used to thinking about on this planet.

NARRATOR: Mono Lake is so salty that almost nothing can live here, so searching for life here offers similar problems to Lake Vostok. Rather than hunt for specific organisms, this team looks for the clues life leaves behind, such as changing oxygen levels in the water indicating its being used by living creatures. Ken Nealson is using an ingenious machine that measures the percentage of dissolved oxygen in water. It’s called a hydrolab. At key points in the lake he finds a sudden change in the oxygen levels. It’s a classic signature of life.

KEN NEALSON: If we saw this steep profile indicative of oxygen consumptions as we went into Lake Vostok you would be pretty convinced of two things. (1) that there was probably life in the lake and (2) that that was the point to go look for it.

NARRATOR: But that’s just the beginning. Having found where to look the Vostok robot will need to analyse a sample of water to be sure it’s found life. This is what the robot might find, unidentified microscopic filaments in its water sample.

KEN NEALSON: Most biologists would say that looks like life, but that’s not good enough. You can form filaments of things without them being alive, so you also need to know what it's made of?

NARRATOR: The robot will need to examine the filament at the molecular level. What it needs is a spectrometer. By firing a laser at a sample and measuring the reflections a spectrometer can actually identify the molecules it’s looking at.

KEN NEALSON: From the read-out we see peaks that tells us there’s DNA-like molecules, protein-like molecules and quinone-like molecules, all characteristic of life.

NARRATOR: This molecular signature leaves no doubt. The filament can only be a form of life. But other scientists have different ideas about the equipment that should be on board the Vostok robot. Years of development lie ahead.

CYNAN ELLIS-EVANS: Very quickly when we started assembling our wish list of, of tests we’d gone up to 20 or 30 different experiments.

NARRATOR: The Vostok robot would need to contain a whole range of devices to help it find life. The hydrolab; a spectrometer; a video camera; lights; microscopes; sensors to measure pressure, water chemistry and temperature; a computer. And the most daunting challenge is that all these and more have got to fit in to a robot the size of a 'squeezy' bottle because that’s all they can fit down a bore-hole through 4 kilometres of ice, but the problems don’t stop there.

CYNAN ELLIS-EVANS: People are always coming up with the idea that the technological issues they’re associated with miniaturising equipment to go down the bore-hole are going to be the, the really serious issues of Lake Vostok, but to my mind a much more pressing issue and one that really is going to govern what we do is the issue of contamination.

NARRATOR: For millions of years Lake Vostok’s pristine waters have been sealed off by the ice above it. The great challenge now is to find a way of getting the robot into the lake without breaking this isolating seal. The robot would need to be put inside a probe for its journey, but how to get the probe and its robot down through 4 kilometres of ice and into the lake. The risk of contamination prevents NASA from using the Russians’ existing drill hole, even thought it’s temptingly close to the lake. So NASA have come up with an ingenious alternative. They could melt their way down.

FRANK CARSEY: We need to develop a vehicle that will move through the ice melting its way.

NARRATOR: Hot jets of water would pump out of the probe.

FRANK CARSEY: We have to do this with the, the hole behind us sealed shut.

NARRATOR: As it sinks through the ice the melt water left behind would re-freeze sealing the probe off from the surface.

FRANK CARSEY: In addition, we have to do this work under the pressure of 4 kilometres of ice so everything that we build has to be capable of survival in this very high pressure.

NARRATOR: There are few materials strong enough to withstand these crushing forces. The current best bet is titanium.

FRANK CARSEY: But now we have a final step. The final step is that we want to prevent the probe from transporting bacteria from the ice and from the air into the lake.

NARRATOR: They’ve come up with an elegantly simple solution. Just before the probe reaches the bottom of the ice sheet it could stop and inside its icy cocoon it could give itself a sterilising bath. Finally the clean probe at the end of its journey would release the robot to motor off in search of life. But it will be many years before this planned robot becomes a reality.

FRANK CARSEY: My guess is that we will be exploring Lake Vostok in something like 5 years. Whether we expect to have an observatory in the lake for at least a year and possibly for several years there is nothing on the probe in the current design that would get used up. We do not expect to get the probe back.

NARRATOR: So the robot will have a one-way ticket. It will never see the light of day again, but NASA hope that when it does finally enter Lake Vostok it will help to unravel some of the secrets of the universe.

Source: BBC

Documentary Description

It sometimes seems as if our planet has no secrets left - but deep beneath the great Antarctic ice sheet scientists have made an astonishing discovery. They’ve found one of the largest lakes in the world. It’s very existence defies belief. Scientists are desperate to get into the lake because its extreme environment may be home to unique flora and fauna, never seen before, and NASA are excited by what it could teach us about extraterrestrial life. But 4 kilometres of ice stand between the lake and the surface, and breaking this seal without contaminating the most pristine body of water on the planet is possibly one of the greatest challenges science faces in the 21st century. In 1957 the Russians established a remote base in Antarctica - the Vostok station. It soon became a byword for hardship - dependent on an epic annual 1000km tractor journey from the coast for its supplies. The coldest temperature ever found on Earth (-89°C) was recorded here on the 21st July 1983. It’s an unlikely setting for a lake of liquid water. But in the 1970’s a British team used airborne radar to see beneath the ice, mapping the mountainous land buried by the Antarctic ice sheet. Flying near the Vostok base their radar trace suddenly went flat. They guessed that the flat trace could only be from water. It was the first evidence that the ice could be hiding a great secret.

But 20 years passed before their suspicions were confirmed, when satellites finally revealed that there was an enormous lake under the Vostok base. It is one of the largest lakes in the world - at 10,000 square km it's about the extent of Lake Ontario, but about twice as deep (500m in places). The theory was that it could only exist because the ice acts like a giant insulating blanket, trapping enough of the earth’s heat to melt the very bottom of the ice sheet. Biologists believe that because the lake has been cut off from the rest of the planet for 15 million years or more - well before the human race evolved - microbial life in the lake could have quietly been evolving into strange and unique forms. It’s a uniquely hostile environment for life - permanently low temperatures, hundreds of atmospheres of pressure, and no light for photosynthesis. In fact, as NASA have realised, the conditions directly replicate those found on Europa - the icy moon of Jupiter. So finding microbial life in Lake Vostok has a greater significance, but what are the odds of finding life in a cold, dark world?

A discovery in Romania sheds new light on how life might survive in Lake Vostok. Shafts sunk into limestone by the Black Sea resort of Moville penetrated a previously unknown cave. Until that point it had been completely cut off from the surface - so just like Lake Vostok it’s an isolated world, with no light for photosynthesis. Scientists were surprised to find life not only existing, but thriving and found 33 species entirely new to science in the Romanian cave. The secret of the cave’s ecosystem was microbes that had adapted to live on chemicals found in the cave’s pools. Instead of using light to photosynthesise, these microbes used hydrogen sulphide in the water as their energy source - a process known as chemosynthesis. Now new research by geologists suggests that hot springs could be present in Lake Vostok, dramatically increasing the chances that it could be home to exciting new forms of bacterial life. But how to get into the lake?

At the Vostok base itself scientists have been drilling down into the ice beneath the base for more than 10 years. The ice core they’ve extracted contains information on the Earth’s climate over the last half million years. When the lake was discovered they realised they were close to penetrating the ice above it, and gaining the first access ever to it’s pristine waters. But there was a problem… The drilling operation involved 50 tonnes of kerosene, used to keep the drill hole open. If the drill went into the lake, the purest body of water on the planet would have had its first oil slick. So the drilling was stopped 120m from the surface of the lake. However, there is another type of contamination, in a way more threatening than kerosene pollution, and that is the introduction of bacteria from the surface. At the moment, science is struggling to devise a high-tech robot probe that will be sent down 4km of ice, into the lake to search for signs of life. The challenge is to create a probe that will produce zero contamination. But now scientists have realised that they already have what they want, right in their very hands. The last few metres of the ice core drilled out on the the way down to lake Vostok, is actually lake water that has frozen onto the bottom of the ice sheet. The question is does this frozen chunk of Lake Vostok's water contain life, and if so, how can it be proved that this is life from the lake, and not contamination from the world above.

Source: BBC


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