High elevation peatland ecosystems in the Tibetan Plateau (TP) store large quantities of carbon that are susceptible to change as the current trend in temperature increase continues. This project will study the vulnerability of peatland ecosystems to changes in temperature by quantifying changes in transit time, the time it takes carbon atoms to travel through the peatland system. We will quantify transit time by 1) measuring the radiocarbon signature of respired carbon dioxide from the peat system under ambient and warming conditions; 2) developing a simulation model that integrates information on radiocarbon and carbon fluxes to obtain transit time distributions.
We will take advantage of an ongoing soil warming experiment in the Zoige peatlands of the Qinghai-TP. Respired CO2 will be sampled from warming and control plots for radiocarbon measurements. In addition, incubation experiments using soils from the region will be used to obtain radiocarbon values in respired CO2 and bulk soil under controlled laboratory conditions. These data will be used to developed a simulation model that represents the dynamics of soil carbon in different fractions, and their response to changes in environmental factors such as temperature, soil moisture, and oxygen concentrations. As a final outcome, we expect to obtain an estimate of the effect of warming on the timescale of carbon cycling in these high elevation peatlands. In particular, we are interested in studying whether warming reduces the time that newly fixed carbon stays in these systems.
This project will be conducted in close collaboration with partners from the Institute of Botany of the Chinese Academy of Sciences. A soil warming experiment has been installed in high-elevation peatlands of the Qinghai-TP in dry and wet sites. CO2 fluxes are measured with an open top chamber system, and research is under way to quantify transformations of organic matter using radiocarbon and molecular biomarkers. In this collaboration, we will focus on the gas phase of organic matter transformations. Together, we expect to contribute to a better understanding of the dynamics of high elevation peatlands under climate change.
Dr. Carlos A. Sierra, MPI for Biogeochemistry Jena
Prof. Dr. Georg Guggenberger, LU Hannover
Prof. Dr. Xiaojuan Feng, Institute of Botany CAS