Microbial CH4 and CO2 Fluxes and C Stabilization Mechanisms in Soils -- supplement to Proposal 47865
EMSL Project ID
49528
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.
Project Details
Start Date
2016-07-11
End Date
2016-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members