Why is the exploration of Subglacial Lake Ellsworth taking place?
To answer two science questions:
1. ‘Search for life’
Is there life in the lake? If so, what form does it take? We expect to find microbial
forms of life
If there’s no life in the lake that will be even more exciting as, so far, wherever
there’s water on Earth, there’s life
If there is no life in the lake we will have found the limit at which life can exist
on our planet
2. ‘Secrets in the sediments’
What can the sediments tell us about Earth’s past climate? By analysing the sediments
to see if they come from a marine or glacial environment we can tell if the West
Antarctic Ice Sheet (WAIS) above has ever collapsed in the past
If the WAIS has collapsed – what was the climate like when it did and how far off
are we from reaching similar environmental conditions? This has implications for
2. History of subglacial lake exploration
16 years ago the scientific community came together to discuss subglacial lakes –
it was agreed that these lakes could potentially offer vital clues about life on
planet earth and their lake-bed sediments could reveal a story about past climate
However, the technology simply didn’t exist for getting into these lakes.
NERC awarded the SLE consortium with the largest sum of money ever given – around
£8m. The SLE consortium has spent the past three years designing and building a:
Hot water drill
Water sampling probe
16 years of planning will result in:
3 years of research and development
3 month field season
Finally, just 24 hours to get into the lake once the borehole has been made!
3. Timeline of this year’s field expedition
22 October - Chris Hill (BAS), Andy Tait (BAS), Andy Webb (BAS), Ed Waugh (NOC) and
Robin Brown (NOC), fly from the UK to Punta Arenas in Chile
2 November ‘Union Glacier Crew’ Andy Webb (BAS) and Ed Waugh (NOC) fly into Union
Glacier to make preparations for the tractor train journey, which they are accompanying
5 November Pete Bucktrout (BAS camera man) flies from UK to Punta Arenas in Chile
7 November ‘Rothera Engineering Crew’ Chris Hill (BAS), Andy Tait (BAS), Pete
Bucktrout (BAS), Robin Brown (NOC), Riet van de Velde (BAS) and Scott Iremonger (BAS)
fly into BAS Rothera Research Station on the Antarctic Peninsula
12 November ‘Rothera Engineering Crew’ fly from Rothera in a Twin Otter to the Lake
Ellsworth site in preparation to greet the tractor train when it arrives from Union
18 November Tractor train leaves Union Glacier – roughly a three day trip through
the Ellsworth Mountain Range to the Lake Ellsworth drilling site
25 November ‘Science Crew’ David Pearce (BAS), Dom Hodgson (BAS), Martin Siegert
(Uni of Bristol), Martyn Tranter (Uni of Bristol) fly from UK to Punta Arenas in
27 November ‘Science Crew’ fly from Punta Arenas to BAS Rothera Research Station
30 November Full camp site established
2 December – ‘Science Crew’ David Pearce (BAS), Dom Hodgson (BAS), Martin Siegert
(Uni of Biristol), Martyn Tranter (Uni of Bristol) fly from Rothera to Lake Ellsworth
5 December Begin priming the hot water drill
12 December Start drilling (roughly 100 hours of drilling)
18 December First samples retrieved
2 January ‘Science Crew’, Pete Bucktrout (BAS) and samples fly back to Rothera
15 January Drilling kit back to Union Glacier
27 January Remaining crew fly back to UK
4. About Lake Ellsworth
Where is it?
Buried under 3km of ice on the West Antarctic Ice Sheet
Why is it liquid and not frozen?
Geothermal heat from the Earth’s core and the pressure of the ice above keeps it
What size is it?
Equivalent to Lake Windermere in the UK – 12km long, 3km wide, 150m at its deepest
How did you map the lake?
It took two field seasons in 2007-08 and 2008-09 to use ground penetrating radar
to map the lake below. The team was led by Andy Smith (BAS), Neil Ross (University
of Edinburgh) and John Woodward (University of Northumbria)
How long has it been isolated?
Anything from 100,000 years up to 1 million years!
Why did you choose Lake Ellsworth if there are more than 400 discovered so far in
One of the more ‘accessible’ lakes to get to (near an operational base – ALE, Union
Small and therefore easy to understand
Near an ice divide where lake access is not complicated by ice flow
Enclosed topographically, and therefore resistant to ice sheet changes that might
occur over glacial cycles
Close to the logistical hub at Union Glacier, from which heavy loads can be input
from South America to Antarctica and deployed to the lake sit
5. Getting to the Lake Ellsworth drilling site
How far away is the Lake Ellsworth site?
Nearly 16,000km from London!
How long did it take for the people to travel to Lake Ellsworth?
Getting into the deep field is not fast and not easy! Everyone had to fly first from
the UK to the very southern tip of Chile, then fly on to the Antarctic continent
before taking another flight on a smaller plane (which lands on skis - Twin Otter)
into the deep field. In total this amounts to around five days of flying.
How did you get all the equipment in?
Shipped from UK to Punta Arenas in Chile
Flown in a Russian Ilyushin (heavy cargo aircraft) from Punta Arenas to a blue ice
runway called Union Glacier on the West Antarctic Ice Sheet (via ALE – Antarctic
Logistics & Expeditions – an independent operator)
Tractor train towed all the containers from Union Glacier to the drilling site –
250km through the Ellsworth Mountain range (heavily crevassed and difficult terrain
ranging from very soft snow, to very hard sastrugi)
6. What equipment was shipped / flown in and when?
Stage one of the mission (season 1, Nov 2011): 70 tonnes of equipment including the
hot water drill system
Stage two of the mission (season 2, Nov 2012): 30 tonnes of equipment including two
water-sampling probes, two sediment corers
7. On the Lake Ellsworth drilling site
What time zone is the team working on?
Rothera time zone – 3 hours behind the UK
What’s it like on site?
-25°C and blowing 20 knots of wind
How will the field team be living?
Sleeping in four-man clam tents with large weather havens used for the work areas
(banks of laptops, communications, eating etc.)
Martyn Tranter, Scientist - ‘search for life’ in the lake water (University of Bristol)
8. Drilling the borehole
How are you getting into the lake?
Using hot water drilling - the cleanest, fastest way to penetrate the lake
Hot water drilling is not a new concept, but never been done on this scale before
and never in a sterile way
Designed and built by British Antarctic Survey
3.2km continuous hose built by a company in the UK (only two companies could build
a continuous hose this long – both UK based)
Needed a continuous hose because the drill head is heavy and didn’t want the hose
to break at the joints
Hose is 50mm in diameter
Nozzle system at the end of the hose is 1.4m long, made of brass and weighs 200 kilos
Water is pressured to 2,000 PSI
Water is heated using a 1.5MW boiler to 90°C
30,000 litres of water is stored on the surface of the ice in each surface tank –
there are three tanks in total (5.5m wide x 1.5m deep)
The borehole will be 360mm wide and then will start to re-freeze immediately because
we are not using any fluids to keep it open (for sterility reasons)
The borehole will be usable for just 24 hours before it freezes up and becomes too
narrow to get the equipment down it
9. Sampling the lake
What order does everything happen in?
300m borehole drilled and then stopped while a cavity is created
Second borehole is drilled into the cavity and out the other side, all the way down
to the lake
Cavity is what controls the pressure of the water in the lake – preventing a geyser
from bursting back up through the borehole and spilling out over the surface of the
Drilling slows when nearing the lake
Drill removed from borehole
UV probe lowered down the borehole for final cleaning
Water sampling probe is deployed – it goes right to the bottom of the lake capturing
water samples and grabbing a small sample of the ‘goo’ sitting on the lake bed (this
is where any life could be living)
Then the sediment corer is deployed – sent to the bottom of the lake to try and capture
a 3m sediment core
Borehole may be re-reamed providing everything has gone well and then the second
probe/corer will be deployed
Designed by Dom Hodgson from BAS and Mike Bentley from the University of Durham,
built by UWITEC in Austria
Sediment coring is not a new concept, but this design is brand new and tailored to
the needs of SLE
Remote controlled from the ice surface
10. Sterility issues
Sterility is at the heart of this project and has been from the outset…why?
So as not to invalidate the samples – the lake is a pristine environment and we want
to collect pristine samples, not to be sampling something we’ve taken down there
How can you be sure you’re not contaminating the lake?
All equipment has been cleaned down to ‘viral levels’ (or pharmaceutical levels)
– similar to space industry standards
Each component of each probe went through a four stage chemical wash followed by
soaking in hydrogen peroxide vapour (HPV) within a sterilisation chamber
Then everything was packaged into a sterile container for shipping
All equipment will be re-sterilised using HPV on site just before going down the
borehole and it will be passed through a UV bracelet at the neck of the borehole
The water used for the drilling (from snow melted on site) will be passed through
a four-stage filtration system and cleaned to pharmaceutical levels (down to 0.1
microns), given UV treatment then heated to 90°C
All sterility preparations made and managed by NOC
11. About the consortium
SLE is a consortium programme, including which institutions?