[Tony Spencer]

Tony Spencer  asked the Naked Scientists:
   
Re the Special on sub glacial lake

Surely there will be a huge pressure problem when they break through, 3.2km of ice will be almost 2 tons per square inch, they will surely have a huge gusher when they penetrate.

Whilst they are careful to not contaminate, is there not a danger of destroying the ecosystem by

1) reducing the pressure may explode any life that is adapted to high pressure or cause severe problems

2) the pressure presumably helps keep the ice layer intact, and reducing the pressure might make the overlying ice crack and break up

If a high pressure stream of water gushes up, will that not impede the closing of the hole as they expect?

Tony Spencer

What do you think?

[rooster]

Hi Tony,

You are absolutely right, but rest assured it has been taken into consideration.

The lake will be at around 300 bar of pressure and there is 3.2km of ice above it. When we drill down to the lake, we aim to keep the drilled hole (borehole) filled with the sterile water used for the drilling operation. If we keep 3000m of water in the borehole, this will equal the pressure in the lake meaning that there will not be any major pressure fluctuations at the point of breaking through. Hence no geyser and no cracking of the surface ice!!!

Hope this helps,

Chris Hill
Programme Manager
Subglacial Lake Ellsworth

[chris]

Thank you, Chris.

[imatfaal]

Cool answer from the horse's mouth!

[damocles]

For those not aware of this:

Simple, useful, and pretty accurate approximation:

Every 10 m of ocean depth = 1 atm (1 bar) extra pressure.