2024 Abstracts

Disentangling the Impacts of Warming and Drying on Peatland Ecosystems


Xiaojuan Yang1* (yangx2@ornl.gov), Daniel Ricciuto1, Xiaoying Shi1 , Verity Salmon1, Colleen Iversen1, Rich Norby1,2, Jeffrey Warren1, Peter Thornton1, Paul Hanson1, Melanie Mayes1


1Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN; 2Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN



Peatland ecosystems play significant roles in the global carbon cycle. Although only covering 2 to 3% of land’s surface, peatland ecosystems store about one third of global soil carbon (C). Warming in northern peatland may accelerate the soil carbon decomposition and lead to rapid release of carbon dioxide (CO2) into the atmosphere, driving a positive land carbon-climate feedback. In addition to the direct impacts of warming on plant physiology, ecosystem respiration and community composition, warming could lead to the drop in the water table, which could also have important consequences for peat decomposition, community composition and ecosystem functions. The objective of this study is to disentangle the impacts of warming and drying on peatland ecosystems using a modeling approach at the Spruce and Peatland Responses Under Changing Environments (SPRUCE) site. Specifically, researchers use ELM-SPRUCE, a version of the E3SM (Energy Exascale Earth System Model) land surface component (ELM) for peatlands, to address the following questions: (1) Is ELM-SPRUCE able to capture warming responses under ambient CO2?; and (2) How much of C loss at SPRUCE is due to direct warming? How much of C loss at SPRUCE is due to changes in water table associated with warming? How much of C loss at SPRUCE is due to loss of sphagnum cover?