Exploring the Linkage Between Root Chemistry and Belowground Microbial Communities

The goal of this project was to understand which plant traits affect the potential for a tree\u27s root carbon (C) to be stored in the soil to better improve accounting of C in forests and changing climates. Previous studies have demonstrated that roots of different tree species decompose at different rates depending on their chemistry and morphology. However, such information does not address how much root C is incorporated into soil microbial biomass, respired, or leached away to dissolved organic C pools. We explored the fate of those decomposed compounds by observing microbial biomass through two techniques, direct microscopy and fumigation, in addition to microbial respiration. The roots of four tree species were analyzed and their chemical composition was quantified. Preliminary results suggest that root morphology influences the fate of decomposed C. A significant trend was observed where thicker roots - roots that are more chemically labile and easier to break down – result in greater microbial respiration. Surprisingly, however, both thick and thin roots yield the same amount of microbial biomass. These results indicate that microbial communities decomposing different root types may have different respiration rates per cell. Further studies of root composition and morphology and effects on microbial physiology will aide in understanding of future ecosystem C dynamics.