Methane consuming microbes combat climate change

Methane consuming microbes combat climate change

A Lincoln University scientist is thinking small to help solve a big problem—climate change.

Dr Sally Price, a senior researcher at the Faculty of Agriculture and Life Sciences, is looking to raise funds so she can develop a set of guidelines for farmers to encourage the growth of naturally occurring methane-consuming soil microbes, called methanotrophs.

Methane is expelled by cows and other ruminant livestock through flatulence, and is a potent greenhouse gas which contributes to climate change.

She has been undertaking periodic research over the last 15 years into the role the microbes play, and has found the root systems of trees and shrubs help to break up the soil and allow the methane to travel down to the microbes.

Minimising compaction of the soil and incorporating organic residues can also make a difference to the microbial communities and increase methane consumption.

‘’The good news is that most soils can act as ‘sinks’ for methane but the ability to do this ranges from 5 to 15 percent of their potential in dairy, ungrazed pasture, sheep pasture, and cropping soils, to between 30 to 50 percent in shrubland and pine forest,’’ Dr Price said.
She said the working of the animal’s digestive processes was not well enough understand to stop methane production so the focus had to be on other measures.

Climate change was a reality and the guidelines would help farmers do their bit, but also had benefits for them as well.

‘’Many factors influence the effectiveness of soil methane bacteria¬, with the soil water content, aeration and disturbance being the greatest variables.’’
She said these factors were also vital to the maintenance of soil health, so following the guidelines in order to encourage microbe growth and methane consumption would lead to better soil.
The measures could include putting land aside for planting trees and shrubs without putting animals on it. Soil methane uptake rates had shown signs of improvement approximately 10 years after the introduction of shrubland into unimproved pasture. Afforestation with quick-growing pine trees had shown substantial methanotrophic activity could be restored in approximately 30 years.

In the future it could be regulated for as part of efforts to meet targets to reduce greenhouse gas emissions, Dr Price said, but for now it could just mean a mind-shift for farmers.

“It is important that land managers become aware of how to enhance this natural yet important process to aid reductions in anthropogenic (human-caused) methane emissions. It all helps,’’ Dr Price said.

Farmers today had to know a lot about science in their role but now also needed to take on board what was happening on the microscopic scale as well.
‘’They (the microbes) are actually driving the farm,’’ Dr Price said.

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