A study by Professor Richard Harper from Murdoch University and Professor Mark Tibbett from Cranfield University in the UK has revealed that deep soils store up significantly more carbon than previous estimates have suggested.
“Soils represent a large component of global carbon stock and measurements are typically taken from the first 30 centimetres of soil,” said Professor Harper.
“Many soils are much deeper than that, particularly in un-glaciated landscapes like the Amazon or Australia, and roots have been found tens of metres below the surface.
“We were interested in finding out whether those estimates from the top layer of soil were painting an accurate picture.”
The researchers took extensive samples down to 40 metres below the surface of the old, highly weathered landscape of southern Western Australia.
“We found carbon in small concentrations all the way to the bedrock, which in total measured up to five times more than commonly reported carbon levels in soils,” said Professor Harper.
“This may have profound implications for managing climate change as the soil represents one of the world’s largest carbon stocks, and this deep carbon has been previously overlooked,” Professor Tibbett said.
“And understanding of carbon cycling is vital for combatting global warming, and soils are crucial, as they hold the largest terrestrial store of carbon worldwide.
“Not only do we anticipate that this work will require a revision of global soil carbon estimates, but we need to establish how changes in land use and climate can affect them.”
The team have published their findings in the prestigious international journal Plant and Soil.