Microbial CH4 and CO2 Fluxes and C Stabilization Mechanisms in Soils
EMSL Project ID
47865
Abstract
Current versions of the Community Land Model (CLM) do not represent the soil biogeochemical mechanisms controlling the fluxes of CO2 and CH4, two known greenhouse gases (GHG).. This failure is largely because little is known about the dynamics of these processes within natural soils, and the influence of changing climatic conditions (temperature and precipitation) on both overall (regional) fluxes and local (microbial) functions. We hypothesize that the secondary effects of the changing climate, ie, shifts in oxic/anoxic conditions and in microbial communities, drive local, microsite processes that need to be specifically represented in biogeochemical models to enable robust scaling of these processes to regional applications. We have selected a hydraulic gradient across the Disney Wilderness Preserve (DWP), FL as the primary location for our soil core sampling. This site experiences cyclic hydraulic inundation that generates bursts of CO2 and CH4 emission; DWP is also instrumented with multiple flux towers that will allow detailed mechanistic studies to be integrated with landscape scale changes. These cores will be studied as both intact and dissected cores using multiple capabilities at EMSL to reveal the interdependency between the geochemical oxic/anoxic conditions, soil macropore network connectivity, quality of soil organic matter, microbial community function, and ultimately the production or consumption of CO2 and CH4. Our experimental studies involve two newly developed, spatially-resolved high resolution mass spectrometry techniques for the analysis of soil organic matter -- nanoDESI and LA-AMS, as well as LC-FTICR techniques for the analysis of dissolved organic matter. We will use pyrosequencing of extracted DNA to evaluate microbial community functional potential. We will use X-ray tomographic imaging of the core macropore networks and integrate this experimental data with microbial metabolic process modeling to understand how cyclic changes in hydraulic conditions drive C degradation, GHG production and migration. Other sites that present ecosystem, or biogeochemical features that may enrich our understanding of C flux mechanisms will also be investigated, as appropriate.
Our research will result in the following outcomes: 1) mechanistic understanding of the belowground process that govern the balance of CO2 and CH4 released to the atmosphere; 2) association of methanogenic and oxidative processes with distinct soil organic matter; 3) determine the relative importance of soil characteristics (depth, water saturation, O2 availability) on CO2 and CH4 production and emission to atmosphere; and determine the whether climatic fluctuations results in more C loss than currently predicted by CLM.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2013-10-01
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Bailey VL, AP Smith, MM Tfaily, SJ Fansler, and B Bond-Lamberty. 2017. "Differences in Soluble Organic Carbon Chemistry in Pore Waters Sampled from Different Pore Size Domains." Soil Biology and Biochemistry 107:133-143. doi:10.1016/j.soilbio.2016.11.025
Bond-Lamberty B ,Bolton H ,Fansler S J,Heredia-Langner A ,Liu C ,McCue L Ann,Smith J L,Bailey V L 2016. "Soil respiration and bacterial structure and function after 17 years of a reciprocal soil transplant experiment" PLoS One 11(3):e0150599. 10.1371/journal.pone.0150599
Yang X, C Liu, Y Fang, R Hinkle, H Li, VL Bailey, and B Bond-Lamberty. 2015. "Simulations of Ecosystem Hydrological Processes Using a Unified Multi-Scale Model." Ecological Modelling 296:93-101. doi:10.1016/j.ecolmodel.2014.10.032