Wetlands around the world are in danger of being drained for activities such as agriculture. Because little is known about their net emissions of greenhouse gases, it’s difficult to predict the effect of this drainage on climate. A recent Canadian study published at Environmental Research Letters examined this, reports Liza Kalaugher at environmentalresearchweb. “Although we know that tidal salt marshes are important sinks for the main greenhouse gas carbon dioxide, any accounting for carbon credits should include other more potent greenhouse gases that can be emitted from wetlands,” noted study co-author Gail Chmura of Canada’s McGill University. Wetlands typically contain little or no oxygen, preventing carbon from decomposing and being released as carbon dioxide. But other microbes can produce the extremely powerful greenhouse gases methane and nitrous oxide. That said, these microbes may be outcompeted by sulphate-reducing bacteria, which tend to thrive in sulphate-rich conditions, such as tidal wetlands with high salinity. And indeed, the team concluded that as long as the marshes were not polluted by human based nutrients, and saline enough, they were important for storing carbon. Preserving them is important.
Salt marshes confirmed as carbon sink
25 Nov, 2011
Even when emissions of methane and nitrous oxide are included, two locations in Canada act as net greenhouse-gas sink