Soil processes govern the largest terrestrial carbon pool, but describing the complexmechanisms that control these processes has proven difficult. A soil region particularly
important to terrestrial C cycling is the rhizosphere and its underlying mechanisms.
Rhizosphere mechanisms are complicated to experimentally capture because their spatial and
temporal micro-scale (μm - cm) dynamics fall outside of the methodological reach of
traditional experimental techniques. By employing microdialysis to simulate rhizosphere
dynamics and simultaneously observing pCO2 with the non-toxic and stable fluorophore 8-
hydroxypyrene-1,3,6-trisulfonic acid (HPTS), we are able to simplify and explore otherwise
complicated microbial processes in a manner that minimizes disturbances. With the
microdialysis system, an area of increased respiration around the microdialysis tip was
successfully established and measured in the majority of replicates in a 24 hr time-series via
a ratiometric fluorescence analysis. Because this method allows for the simulation of root
exudation and analysis of subsequent microbial activity, it is a potential tool to study
rhizosphere processes in a laboratory setting, though further development is needed.