 Shifts in soil microbial use of recalcitrant vs. labile substrates in a pine forest with elevated CO2 |
| Predicting belowground responses to elevated CO2 requires an integrated understanding of soil organic matter transformations and the microbial activity that governs them. It remains unclear how the microorganisms upon which these transformations depend will function in an elevated CO2 world. This study examines soil organic matter transformations and microbial metabolism in soils from the Duke Free Air Carbon Enrichment site in North Carolina, USA. We are assessing microbial respiration in soils with and without elevated CO2 exposure and N fertilization during soil incubations, some of which have been amended with 13C substrates. We also are tracing the depleted C isotopic signature of the supplemental CO2 into soil organic matter and the soils’ phospholipid fatty acids (PLFA), which serve as biomarkers for living cells. Thus far, we have observed changes in the soil microbial community that suggest increasing activity levels with lower N availability in organisms that are well adapted for using relatively recalcitrant substrates as an energy source. This project is in collaboration with Dr. Sue Ziegler at Memorial University of Newfoundland, Canada. |