Far from being environmental saviours – work in 2006 suggested plants may actually contribute to greenhouse gas emissions. Now however, a father-daughter team has restored plants to their rightful place as greenhouse gas heroes.
Previous work had blamed plants for producing large quantities of methane themselves – counteracting their useful quality of removing carbon dioxide from the atmosphere for utilisation in photosynthesis. However, Professor Euan Nisbet at Royal Holloway and Dr Ellen Nisbet at Cambridge, have now been able to show that the methane emitted by plants is not made directly by the plants themselves, but made by bacteria in the soil. Leader of the Cambridge team, Professor Christopher Howe, said: “The imbalance that causes global warming comes from human activities that increase the atmospheric levels of greenhouse gases such as carbon dioxide”.
The dissolved methane in the soil is then taken up by the roots of the plant and recycled through the plant tissue before being released into the atmosphere by the leaves. Thus the responsibility of contributing to global warming rests with the soil bacteria and not the plants.
Dr Ellen Nisbet said: “It is a relief to know that plants are not guilty. Growing plants remove enormous amounts of carbon dioxide from the atmosphere each day”.
By Georgina Lavender