Scientists have discovered a new biomarkers of CO-2 exposure from the ancient ice sheet that could shed new light on past climate change.
In a study published in the journal Nature, researchers led by Professor John Foulds of the University of Western Australia (UWA) and colleagues from several institutions including the Australian Antarctic Division and NASA’s Jet Propulsion Laboratory (JPL) and the University and University of Queensland, found a molecular signature of CO 2 in the sedimentary rock of the North-West Ice Shelf in Antarctica.
“The signature is unique and indicates that this ancient ice shelf is very, very old and very thin,” Dr David Lea, a lead author of the study, said.
“This was the first time that we have identified an individual signature of carbon dioxide in a whole ecosystem.”
Dr Lea said the study showed that a specific set of CO molecules, known as CO-1-2, had survived for billions of years.
“What you would expect would be a very low abundance of these molecules, which is not something we would expect in the modern climate,” he said.
The team used the isotopic signature to identify the origin of the CO-3 and CO-4 that was found in the Antarctic ice shelf’s sediments.
“When you have these molecules in a sedimentary structure, you can’t just go and take them out and use them as a fingerprint,” Dr Lea explained.
“But when you have a signature, it can be used as a marker to say, ‘Okay, this is the origin for this molecule’.”
It’s really important that we understand what these CO molecules were doing at that time.
“Scientists previously thought that the ancient Antarctic ice had lost most of its CO2 over time, with traces of the molecule still present in the ice.”
Our analysis indicates that some of these traces are still there, and that this is a very old signal,” Dr Fouldson said.
While this new signal was very different to previous studies, it still matched what we expect to see in the fossil record of the past, he said, because the sedimentation rate of the ice was so high.”
It doesn’t really look like any other signature we’ve seen, except for this one.
“We are seeing traces of this molecule that are really consistent with what we see in fossils from other places, which suggests that this signature may have survived for millions of years.”
The research is part of a wider research project to understand the climate of Antarctica, with Dr Leamassa and Dr Frews being involved in the project, along with a number of other researchers.
“There’s a lot more to learn about how the ice sheets were formed and how they changed during the last 10 million years,” Dr Gertrude Bode, who was also a co-author of the paper, said of the Antarctic.
“And the most interesting thing about this research is that we’re getting a very good signal from the carbon isotopes.”