Signs of life from Antarctic lake buried under more than 2,000 feet of ice

American scientists drilled into a lake beneath the Ross Ice Shelf to search for life. Using a sterilized hot water drill, they penetrated the ice while preventing contamination. Pressure management allowed lake water to rise into the borehole. The lake was shallower than expected, filled with sediments. Samples revealed microbes that likely metabolize iron and sulfur using oxygen from melting ice.

What method did scientists use to ensure the drill was free from contamination?

• They used high-pressure air.

• They used chemical disinfectants.

• They used ultraviolet radiation.

• They used boiling water.

Why did scientists pump out thousands of gallons of water during the drilling process?

• To speed up the drilling process.

• To lower the pressure and prevent contamination.

• To increase the temperature of the borehole.

• To create a larger borehole.

What was the actual depth of the lake compared to initial predictions?

• The lake was not measured.

• The lake's depth matched predictions.

• The lake was shallower than predicted.

• The lake was deeper than predicted.

What did the water sample from the lake contain?

• Only sediments.

• Cells that glowed red.

• No signs of life.

• Cells that glowed green.

How do the microbes in the lake likely obtain energy?

• By absorbing sunlight.

• By consuming organic matter.

• By photosynthesis.

• By metabolizing iron and sulfur using oxygen from melting ice.