Natural marine seepage blowout: Contribution to atmospheric methane

[ 1] The release of methane sequestered within deep-sea methane hydrates is postulated as a mechanism for abrupt climate change; however, whether emitted seabed methane reaches the atmosphere is debatable. We observed methane emissions for a blowout from a shallow ( 22 m) hydrocarbon seep. The emission from the blowout was determined from atmospheric plume measurements. Simulations suggest a 1.1% gas loss to dissolution compared to similar to 10% loss for a typical low-flux bubble plume. Transfer to the atmosphere primarily was enhanced by the rapid upwelling flows induced by the massive discharge. This mechanism could allow methane suddenly released from deeper (> 250 m) waters to contribute significantly to atmospheric methane budgets.