Green leaf volatile (GLV) emissions from the central Amazon

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Description

The Amazon Basin is a critical component governing Earth’s climate through large continuous surface fluxes of energy, water, and carbon. In the last decade, the Amazon has suffered two short-lived but severe droughts resulting in extensive tree mortality. Although global climate models predict that Amazonian droughts may intensify in both frequency and duration in the future, several key land-atmosphere processes remain highly uncertain. Laboratory studies have revealed that green leaf volatiles (GLVs) represent a large group of fatty-acid oxidation products known to be released into the atmosphere by plants at high rates in direct response to drought stress and associated environmental conditions including high light and temperature. Chamber studies suggest that once emitted into the atmosphere, GLV oxidation can produce secondary organic aerosol serving as effective cloud condensation nuclei, a process that may play a significant but unknown role in water recycling in the Amazon Basin. It was traditionally considered a minor component of biogenic volatile organic compound (BVOC) emissions from terrestrial ecosystems, but here we report the first in situ observations of highly vertically resolved atmospheric GLV concentrations within and above a primary rainforest during the 2010 drought in the central Amazon.