A new way to locate peat soils using gamma ray detectors mounted on aircraft has been developed by Irish scientists.
Most of Ireland’s peatlands emit carbon because of land drainage and peat extraction over many decades, even though they should be natural carbon sinks. This forced the Government to put in place a programme of rewetting in an effort to reduce Ireland’s greenhouse gas emissions from land.
The Climate Change Advisory Council and Irish Fiscal Advisory Council recommended last week that €1 billion be allocated to restore 80,000 hectares of peatlands and support forestry.
A study led by Dr Eve Daly and Dr Dave O’Leary from the Hydrogeophysics and Remote Sensing research group at the University of Galway provides a much more accurate picture of where peat soils are.
By measuring natural gamma radiation levels in tandem with state-of-the-art analytical techniques and data from the Geological Survey Ireland (GSI) Tellus aerial survey of the entire country, the research team has produced a revised picture of where peat soils are present across 80 per cent of Ireland.
“The findings also offer huge potential to influence policy around land use and interventions to mitigate against greenhouse gas emissions,” the team concludes.
Gamma rays are invisible, high-energy photons, like light, that are released during natural radioactive decay of materials in rocks and soils.
“Peat soils have a unique ability to block this type of naturally occurring radiation, drastically reducing the number of gamma rays detected by the sensor mounted on the Tellus aircraft when flying over peat soils,” Dr O’Leary said.
This gives decision makers and regulators more accurate spatial data on the extent of peat soil in Ireland “and will assist in highlighting specific areas that are suitable, or not, for interventions to mitigate greenhouse gas emissions”, Dr Daly said.
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The research was published in the soils science journal Geoderma.
While peat depth cannot be directly measured, their analysis gives insights into the extent of peat soil and identifies areas where soil “changes from peat to mineral”, which are typically hidden under forests and grasslands.
Using this approach, the area of soil considered “peaty” potentially increased from 24 per cent to 30 per cent.
Soils are a mixture of broken bits of rock, water and air. Peat soils are distinct from mineral soils as they are formed from decaying plant material, mixed with water and air, and contain a very large amount of carbon.
“When waterlogged, this carbon is stored in the soils – and their value has been increasingly recognised. When water is removed, for example via drainage, peat soils then emit carbon dioxide as the decay process restarts,” Dr O’Leary said.
“Few countries have invested in such an incredible data set, which puts Ireland at the forefront of peatland mapping.”
The study, funded by GSI, was conducted in collaboration with researchers at Trinity College Dublin, Teagasc and GSI.
