Bidirectional exchange of methyl halides between tropical plants and the atmosphere

Abstract

Using a stable isotope tracer technique, we studied the exchange of methyl chloride (CH3Cl) and methyl bromide (CH3Br) between plants and the atmosphere in a tropical rain forest in Malaysia. Most plant species examined showed not only production but also consumption of CH3Cl with a large net emission overall. In contrast, CH3Br consumption was comparable to its production, so the net emission was small. The rates of CH3Cl and CH3Br consumption were highly correlated with each other, and their ratio was consistent with reported values in terrestrial ecosystems, where microorganisms are responsible for the consumption. Such microorganisms might participate in the consumption we observed, as the consumption rates were faster in saplings, whose leaves were generally covered by epiphytic microorganisms, than in healthy looking leaves of mature trees. Key Points Tropical plants showed not only emission but also uptake of methyl halides ©2013. American Geophysical Union. All Rights Reserved.