Wednesday, August 5, 2009 - 4:20 PM

OOS 27-9: A traits-based framework to study the intersection of methanotroph community ecology and methane biogeochemistry

Joseph C. von Fischer, Craig R. Judd, and Colleen T. Webb. Colorado State University

Background/Question/Methods

Methane is a potent greenhouse gas whose concentration, in part, is regulated by the uptake of methane by well-drained, oxic soils.  In this process, methane diffuses from the atmosphere into the soil, where it is consumed by methanotrophic bacteria.  Development and application of molecular tools are beginning to reveal previously undescribed clades of methanotrophs that are dominant in many soils, and nascent biogeographic patterns suggest that clades may differ in their ecophysiology.  Although we have a good understanding of how physical processes affect methane uptake, it remains unclear how patterns in uptake are structured by differences in methanotroph community composition as a result of the differences in ecophysiological responses of each clade.   

Results/Conclusions

Here, we identify a set of key traits that are likely to structure methanotroph “performance” (i.e., their rates of methane consumption), and we show how a traits-based framework can integrate functional differences among clades to better predict inter-annual variation in soil methane uptake rates in response to environmental drivers.  This framework also generates hypotheses about controls on methanotroph biogeography, which can be used to predict the longer-term response of methanotrophs and methane uptake to shifts in the climate regime.