PNNL

Abstract

Heterotrophic respiration (RH), the oxidation of organic matter to carbon dioxide by free-living microorganisms, is one of three major processes releasing carbon to the atmosphere, the other two being autotrophic respiration (RA) and combustion. Over long times and large spatial extents these three fluxes roughly equal the amount of carbon being fixed by photosynthesis, at least in upland ecosystems (Frey and Smith 2005). Over short period of time or within small areas changes in the strength of these fluxes can determine when and where an ecosystem is a source or sink of carbon relative to the atmosphere (reference from Hurtt disturbance paper). Thus, the understanding of the biophysical factors that regulate the strength of these fluxes is a current topic of research.