Ancient larvae help climate scientists

Australian scientists are using fossilised larvae as "time capsules" to tell them how climate change has affected the country's weather patterns for the past 21,000 years.

A team from the University of Queensland (UQ) is hoping to use midge larvae fossilised in lake mud to discover how climate systems in south-east Australia responded to Australia's last ice age.

Chief investigator Dr Craig Woodward said the larvae heads were made up of a substance called chitin that is resistant to decay, making them perfect time capsules.

"In the right conditions, the larval head capsules can be preserved for hundreds of thousands of years as fossils in the layers of mud at the bottom of lakes," Dr Woodward said.

He said during the project, the larvae will be extracted from mud from 30 lakes along the eastern coast and their heads will be placed in a machine that turns them into gas.

The gas will provide a "chemical signature" of the lake at the time the larvae were alive, providing a glimpse of weather patterns and rainfall over time.

"In Queensland, when monsoon systems and big storms dump the water into a lake, you've got a chemical fingerprint in that water that's stored in these head capsules," he said.

This information was important as scientists currently had no good grasp on how rainfall varies in Australia over long periods, he said.

Dr Woodward said his project was part of a larger study into the history of the monsoon.

Within that broader study, other information would be gained from pollen and charcoal in the lake mud about how forests and plants had changed and the history of bushfires.