Thursday 25th February, 4 PM CET
Dr. Pierre Delmelle
ABSTRACT: Volcanic explosive eruptions release magmatic CO2in the atmosphere. These eruptions also blanket the landscape with tephra, sometimes across vast areas. The soils that are buried by tephra may become isolated from surface processes. As a result, the microbial decomposition of organic matter is impeded, leading to the storage of soil organic carbon. The question we ask here is whether explosive eruptions sequestrate more carbon in soils than what they emit in the atmosphere. We first test our hypothesis based on a field study at Atacazo volcano, Ecuador. The results of this work are then used to formulate a model that predicts the storage of soil carbon resulting from explosive activity in the Ecuadorian volcanic arc during the Holocene. We conclude that, through time, volcanic eruptions have resulted in a net storage of carbon; the stock being at least two to three times larger than the total magmatic carbon emissions.