April 29 : A recent study by a consortium of Dutch scientists has contradicted a recent study in Nature, which suggested that terrestrial plants might be a global source of the potent greenhouse gas, methane.

The controversial finding and the resulting commotion led the consortium of Dutch scientists to re-examine this in an independent study, which appears in the New Phytologist, where they write that methane emissions from plants are negligible and do not contribute to global climate change.

As part of the research, Tom Dueck and his colleagues grew six plant species in a facility containing atmospheric carbon dioxide almost exclusively with a heavy form of carbon (13C).

This makes the carbon released from the plants relatively easy to detect. If the plants emit methane, it can be easily detected against the background of lighter carbon molecules in the air, as methane contains heavy carbon isotope.

Methane emission was measured under controlled, but natural conditions with a photo-acoustic laser technique.

This technique is so sensitive that it allows the scientists to measure the carbon dioxide in the breath of small insects like ants.

The researchers found that even with this state-of-the-art technique, the measured emission rates were so close to the detection limit that they did not statistically differ from zero.

“To our knowledge this is the first independent test which has been published since the controversy last year,” the researchers wrote in their study.

Conscious of the fact that a small amount of plant material might only result in small amounts of methane, the team sampled the ‘heavy’ methane in the air in which a large amount of plants were growing.

Again, the measured methane emissions were found to be negligible.

The Dutch consortium included scientists from the Plant Research International, IsoLife and Plant Dynamics in Wageningen, Utrecht University, and the Radboud University in Nijmegen. (ANI)