Home Tags Posts tagged with "lake ellsworth"
lake ellsworth
An American attempt to bore down into Lake Whillans, a body of water buried almost 1 kilometer under the Antarctic ice, has achieved its aim.
Scientists reported on Sunday that sensors on their drill system had noted a change in pressure, indicating contact had been made with the lake.
A camera was then sent down to verify the breakthrough.
The Whillans project is one of a number of such ventures trying to investigate Antarctica’s buried lakes.
In December, a British team abandoned its efforts to get into Lake Ellsworth after encountering technical difficulties.
The Russians have taken water samples from Lake Vostok, although they have yet to report any big discoveries.
Lake Whillans is sited in the west of Antarctica, on the southeastern edge of the Ross Sea.
It is less of a lake and more or a dense system of streams, almost like a delta, that covers some 60 square km. The liquid body is quite shallow – just a few metres in depth.
The Whillans Ice Stream Subglacial Access Research Drilling (Wissard) team has been using a hot-water drill to melt a 30-cm-diameter hole through the overlying ice.
An American attempt to bore down into Lake Whillans, a body of water buried almost 1 kilometer under the Antarctic ice, has achieved its aim
Breakthrough to the lake surface was reported on the project’s website.
The intention, now that the hole is secure, is to lower various sampling tools and sensors into the lake to study its properties and environment.
Some of the samples will be assessed onsite at the ice surface in temporary labs, and others will be returned to partner universities for more extensive analysis.
The Wissard blog said the thickness of the overlying ice was measured to be 801m, which agreed well with the estimates from seismic imaging.
More than 300 large bodies of water have now been identified under the White Continent.
They are kept liquid by geothermal heat and pressure, and are part of a vast and dynamic hydrological network at play under the ice sheet.
Some of the lakes are connected, and will exchange water. But some may be completely cut off, in which case their water could have been resident in one place for thousands of years, and that means they probably play host to microorganisms unknown to modern science.
The Whillans area is not as deep as either Vostok (4 km) or Ellsworth (3 km), and its water is exchanged frequently by the under-ice streams over months and years.
Indeed, satellite measurements have revealed the lake rapidly filling and draining. This was evident from measurements of the height of the overlying ice surface, which raised itself in response to an increase in water volume, and then slumped down as the water spread to a new location.
Scientists are keen to study Antarctica’s subglacial hydrological systems because liquid water beneath the ice sheet will influence its movement (the ice above Lake Whillans is moving at about 300m per year). Modeling the sheet’s long-term stability in a warming world has to take this into account.
These under-ice environments may also provide fascinating insights into the potential habitability of some moons in the Solar System.
Europa, a satellite of Jupiter, and Enceladus, which orbits Saturn, both have large volumes of liquid water buried beneath their icy crusts.
The British attempt to search for life in ancient Lake Ellsworth beneath the Antarctic ice-sheet has run into trouble.
The team has reported “a serious problem” with the main boiler used to heat the water that powers a drill.
Work was halted on Saturday in what could prove to be a major blow to the project to investigate sub-glacial Lake Ellsworth.
The aim is to use 90C water to blast a hole through the two-mile-thick ice-sheet to reach the lake waters below.
The research goal is to gather samples of water and sediment to search for signs of life and clues about the region’s climatic history.
The project relies on the successful operation of the hot-water drill which in turn depends on the boiler.
The British attempt to search for life in ancient Lake Ellsworth beneath the Antarctic ice-sheet has run into trouble
Last Thursday the team reported that a key circuit on the boiler – controlling the primary burner – had failed to start.
A back-up burner was fitted which ran successfully for 4-5 days – enough to melt the water needed to start drilling.
The first task was to melt a cavity 300m below the ice to act as a water store to help balance water pressure once the main drilling to the lake started.
In a statement released this morning, the team announced: “Unfortunately, the burner failed at approximately 3:00 p.m. local time on Saturday.”
A replacement component has been ordered and is expected to reach the team in a few days’ time.
“In the meantime, the engineering team is in contact with the manufacturers of the units who are helping them to determine the cause of the malfunction.
“Both units demonstrated the same problem. When the replacement circuit arrives the engineers will work with the manufacturer to go through the set up procedure. The team is hopeful that this will solve the problem,” the statement says.
“If not, a further option is to attempt to bypass the circuit and manually <<drive>> the burner. The team is discussing operating protocols with the manufacturer before exploring this option further.”
A major concern is that the system was designed to be operated on one attempt – to heat the water and melt open the bore-hole without pause to avoid the risk of ice forming inside the drill-pipe.
However, sources at the British Antarctic Survey say there is no issue of any water having frozen in the pipes. They say the system is still “ticking over” with warm water.
In temperatures as low as minus 30C, and in a region notorious for its winds and remoteness, any technical problems of this scale are a huge challenge.
The team always recognized that the project involved high risks – with sophisticated technology in a hostile environment.
It is unlikely that the team will resume drilling before Friday December 21st.
[youtube tL2LtXTe00E]
Final checks are under way in Antarctica before the launch of a daring attempt to investigate ancient Lake Ellsworth beneath the ice-sheet.
Lake Ellsworth lies below ice that is at least two miles (3.2 km) thick.
Its pitch-black waters have remained isolated and unseen for up to half a million years.
This will be the first attempt to extract uncontaminated samples of water and sediment from a body of water so far below the surface.
The investigation is part of a search to understand the limits of where life is possible and, despite the high pressures and lack of sunlight, it is likely that microbes will be detected.
The lake is about 14 km long, 3 km wide and 160 m deep – about the size of Lake Windermere, England’s largest.
In a region of Antarctica notorious for its low temperatures and near-constant winds, operating at this location is a huge challenge.
The project is made all the tougher because of the need for all the equipment to be kept sterile throughout the process.
The team behind the £8m project is readying a hot-water drill that will be used to blast a hole from the surface of the ice all the way down to the lake.
The chief scientist, Professor Martin Siegert of Bristol University, said he had first thought of exploring sub-glacial lakes 16 years ago.
“We’re very excited about this work and we’re very much looking forward to doing science that has taken us so long to plan.
“The first challenge was to develop the equipment and we’ve done that. The second was to keep it clean and we’ve done that. The third was to get it to Antarctica in a clean way and we’ve done that too.
“Now the experiment is set we can hit the Go button.”
Final checks are under way in Antarctica before the launch of a daring attempt to investigate ancient Lake Ellsworth beneath the ice-sheet
A small mountain of 270,000 litres of snow is ready to be shoveled into boilers – the first of a vast quantity needed to produce enough water for the operation.
The water will be filtered to remove any microbes, then screened through ultra-violet light before being heated to 90 degrees C and passed into the drill which will melt a passage through the ice-sheet.
The hot water pipes connecting the boilers have been insulated and in some cases fitted with heating devices. All the key component are wired to relay data. And the drill hose, which is 3.4 km long, has been cleaned and checked.
The drilling operation is expected to last five days and the bore-hole is projected to remain open for no more than 24 hours.
During this brief window, the plan is to lower a sampling probe fitted with HD cameras to gather the first images of the lake and collect water samples.
Next the team hopes to lower a second device which will settle on the bed of the lake and extract a core of the sediment – which should provide an invaluable record of the history of the lake and reveal when it was covered by ice.
Project manager Chris Hill of the British Antarctic Survey described the “funny feeling” of planning the project for so long and now being ready.
In his blog, he wrote:
“The twelve people here have sat around a meeting table on many occasions during that period…but now, for the first time, we are together in Antarctica, at Lake Ellsworth, with all the equipment, as a team and we have to make it happen.
“No pressure then!”
Earlier this year Russian scientists extracted samples from a much larger Antarctic lake, Lake Vostok, though there are questions about the risks of contamination.
And an American team reported last month on the discovery of microbes in Lake Vida, but from far shallower depths than the waters of Lake Ellsworth.
The initial findings of the Lake Ellsworth project should be known in about a week’s time.
[youtube -TVWfu4aPw4]
[youtube wWbznvXPrEU]
