Desert aquifers may serve as huge carbon sinks

New Scientist : A saline aquifer underneath a desert in northwest China has been found to contain surprisingly large amounts of carbon , according to Yan Li of the Chinese Academy of Sciences in Urumqi and colleagues. From water samples taken from the Tarim basin and from nearby rivers and other water sources that feed into it, the researchers have been able to create a timeline of how much and when carbon entered the closed drainage system. They found that the amount of carbon has increased dramatically because of human agricultural practices, which call for overirrigation of crops in desert areas to leach away the salt. The salt washed out of the soil makes its way into the aquifer, and the increasingly salty water is able to absorb and store more carbon than pure water. How much irrigating of deserts occurs around the world is unknown, but if the Tarim basin is any indication, the potential of similar aquifers to serve as carbon sinks could become increasingly important with the onset of global warming.