PARENT SESSION
Oral Session # 50: Forest Ecology III: Modeling; Nutrient Cycling.
Presiding: L Comas
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 100.
Modeling methane consumption and emission between the terrestrial biosphere and the atmosphere.
Zhuang, Qianlai1, Melillo, Jerry1, Kicklighter, David1, Prinn, Ronald2, Steudler, Paul1, McGuire, David3, Felzer, Benjamin1, Hu, Shaomin1, 1 The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA2 Massachusetts Institute of Technology, Boston, MA3 University of Alaska Fairbanks, Fairbanks, AK
ABSTRACT- Methane is an important greenhouse gas that has major natural sources and sinks associated with the activities of soil microbes. As climate changes it is possible that the magnitudes of these sources and sinks will change dramatically. To explore these possible changes we have modified our global biogeochemistry model, the Terrestrial Ecosystem Model (TEM 5.0). The modifications include a revision of our water balance and soil thermal modules, and the development of a new methane dynamics module. The revised water balance model enables us to consider the dynamics of ecosystem hydrology, including water fluxes, soil water content, and water tables on a daily rather than a monthly time step. The revised soil thermal module enables us to more accurately simulate various aspects of soil thermal dynamics in northern ecosystems including soil temperatures, active layer depths, and permafrost dynamics on a daily time step. The new methane dynamics module has been developed to simulate the processes of methanotrophy and methanogenesis, along with the physical and biological transport mechanisms of this greenhouse gas. Our new version of TEM has been run at a daily time step for a variety of sites, from tundra to tropical forests, where methane flux measurements have been made. Preliminary studies show good agreement between the simulated and measured fluxes at most sites. In the future we plan to use the model to examine the methane responses to climate change (e.g. warming and permafrost melting in the Northern Hemisphere) and land-use and land-cover changes (e.g. agricultural activities in Brazil) at regional and global scales. We will also run the model within the MIT Integrated Global System Model (IGSM) framework to examine the feedbacks of methane dynamics between terrestrial ecosystems and the climate system.
Key words: hydrological dynamics, methane emission and consumption, soil thermal dynamics, methanogenesis and methanotrophy