Effects of Global Warming and Elevated Carbon Dioxide on Peatland Ecosystem Productivity and Greenhouse Gas Emissions: A Modeling Study
Authors
Dafeng Hui1* (dhui@tnstate.edu), Jaekedah Christian1, Xiaoying Shi2, Daniel M. Ricciuto2
Institutions
1Tennessee State University, Nashville, TN; 2Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN
URLs
Abstract
Peatlands are important ecosystems storing more than 20% of the global soil carbon. However, the impacts of global warming and elevated atmospheric carbon dioxide (CO2) concentration on peatland ecosystem productivity and soil greenhouse gas [GHG, such as CO2, methane (CH4), and nitrous oxide (N2O)] remain unclear. In this study, researchers simulated the dynamics and controls of peatland soil CO2, CH4 and N2O emissions using a process-based model (Forest Denitrification-Decomposition; Forest-DNDC) under different temperature and CO2 conditions. The simulations were based on the long-term DOE Spruce and Peatland Response Under Changing Environments (SPRUCE) experimental study where spruce peatland ecosystems were exposed under five temperature levels (i.e., +0, +2.25, +4.5, +6.75, +9°C) and CO2 conditions (+0, +500 parts per million). Data measured at the experimental plots from 2015 to 2021 were used to drive and parameterize the DNDC model. Preliminary results showed strong seasonal and interannual variations of net ecosystem exchange (NEE) of CO2 and GHG, especially soil CO2 and CH4. Both CO2 and CH4 emissions increased with temperature increase. With global warming, NEE shifted from carbon sink to source. Elevated CO2 had limited impacts on NEE and GHG emissions. Results of this study could improve understanding of the magnitudes and controls of peatland productivity and soil GHG emissions.