Identifying key mechanisms underlying C cycling dynamics in a vulnerable, highly seasonal tropical dry forest ecosystem.
In dry or semiarid ecosystems, most soil respiration (CO2 production by microorganisms) can occur in large ‘pulses’ immediately following rainfall events. An in-situ rainfall manipulation experiment was combined with a simulation modeling approach to identify the dominant belowground controls on these important CO2 fluxes.
Dissolved organic carbon available to microbes was identified as a key controller of soil CO2 pulses following rainfall events. This relationship can be captured in simple ecosystem models, allowing us to better predict how ecosystem carbon balance will respond to ongoing changes in precipitation regime.
An in situ precipitation manipulation experiment was conducted in a tropical dry forest in Guanacaste, Costa Rica, to better understand the processes underlying rainfall-induced pulses of soil respiration. (Re)-wetting dry soil produced an immediate, substantial pulse of CO2, accompanied by rapid immobilization of N into the microbial biomass. The size of the CO2 pulse following simulated rainfall events was linked to dissolved organic carbon (DOC) availability to microbes. The relationships among soil moisture, DOC, and CO2 fluxes were then integrated into simple biogeochemical models, which could accurately predict observed patterns of CO2 flux in response to rainfall. Together, these data demonstrate that explicitly representing microbial processes in such models can improve our predictions of C cycling under changing rainfall regimes.
Contacts (BER PM)
University of Minnesota
The US Department of Energy, Office of Science, Office of Biological and Environmental Research, Terrestrial Ecosystem Science (TES) Program (award number DESC0014363) and the National Science Foundation (CAREER grant DEB 1053237 to JSP).
Waring, B.G. and J.S. Powers. “Unraveling the mechanisms underlying pulse dynamics of soil respiration in tropical dry forests.” Environmental Research Letters 11(10):105005 (2016). [DOI: doi:10.1088/1748-9326/11/10/105005]
BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER
May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]
May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]
May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]
May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]
Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]
List all highlights (possible long download time)