Antarctic expedition to seek natural atmosphere cleanser in the ice sheet

December 05, 2018

An international team of researchers are drilling into the Antarctic ice cap to find a molecule that helps cleanse the atmosphere.

Antarctica atmosphere

The elusive molecule would help to cleanse the atmosphere of greenhouse gases and ozone depleting chemicals.

This molecule is the hydroxyl radical and it is often called ‘the detergent of the atmosphere’.

The expedition has departed from Australia’s Casey research station and travelled 125 km to Law Dome which rises to an elevation of 1400 m on the Antarctic coast.

The expeditioners will be in this remote site, living in tents, for nearly three months as they drill 250 m into the ice. Ice cores from this depth contain air, trapped in bubbles, that dates from around 1850 AD.

The hydroxyl radical is a naturally occurring, highly reactive molecule that plays an important role in the atmosphere as a natural air purifier by destroying greenhouse gases and ozone depleting chemicals.

However, we have no knowledge of hydroxyl levels beyond the last five decades, leaving a huge gap in our understanding.

ANSTO’s Dr Andrew Smith is part of the ten member expedition team and said the aim of the expedition is to determine the earlier atmospheric history of the hydroxyl radical, back to around 1850 AD.

“This is an exciting collaboration, which has been four years in the planning and will provide important knowledge to better understand our warming planet,” Dr Smith said.

“In order to study the hydroxyl radical beyond the instrumental record we must use naturally occurring radiocarbon.

“ANSTO’s Centre for Accelerator Science is one of the few laboratories in the world that can make these very challenging measurements.”

The scientists are travelling to Law Dome because it provides the special conditions needed for their research. The very high snowfall traps air quickly and preserves it as bubbles in the ice for millennia.

After the ice cores are collected and melted, the liberated air will be shipped to the University of Rochester to separate the trace gases carbon monoxide and methane.

Once separated, the gases are converted to carbon dioxide which is sealed in glass tubes and delivered to ANSTO. Here it is converted into graphite and measured for radiocarbon in ANSTO’s Centre for Accelerator Science.

The expedition is a US-Australian collaborative project titled ‘Reconstructing Carbon-14 of Carbon Monoxide to Constrain Long-Term Atmospheric Hydroxyl Variability’, led by CSIRO atmospheric scientist Dr David Etheridge and University of Rochester scientist, Dr Vas Petrenko.

Originally published by ANSTO.

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