The Effect of Priming on Soil Carbon Dynamics: Development and Investigation with CLM4-BeTR
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Transcript of The Effect of Priming on Soil Carbon Dynamics: Development and Investigation with CLM4-BeTR
THE EFFECT OF PRIMING ON SOIL CARBON DYNAMICS: DEVELOPMENT AND INVESTIGATION WITH CLM4-BETR
JINYUN TANG, W. J. RILEY, C. D. KOVEN, Z. SUBIN AND M. TORN
Funded through CSSEF by DOE-BER
THE MICROBE MODULATED CN SYSTEM
Plants
MicrobesSoil
organic matter
NutrientN,P
Priming
CLM4-BETR: BIOGEOCHEMICAL TRANSPORT & REACTION
CLM4-BETR IMPLEMENTATION
Multi-time stepping Process adaptive 1D generic tracer transport Two-layer surface-plant-atmosphere coupling Multiphase chemistry, fast equilibrium assumption Explicit tracking of fluxes due to: run-off/on, ice/water
phase change, precipitation, dry deposition, ebullition, diffusion
s: solid phaseg: gas phasew: aqueous phase
PRELIMINARY MODEL RESULTS
Single point simulation at Harvard forest
THE MICROBIAL-CN MODEL
PLTR SOM
PSOM
DOM microbes
IMPLEMENT THE GENERIC MICROBIAL-CN MODEL Microbial groups with different
specialties/competitions Different electron acceptors, e.g. aerobic or
anaerobic pathway Dual status, active or dormant (microbial
activity) Multi-substrate feeding, DOC, DOM With colonization capability Step adaptive temporal integration Fully coupled with plants and atmosphere
TEST THE PRIMING EFFECT
Hypothesis: More carbon respired than input under favorable conditions
Model dynamics: Two microbial communities, compete for DOC and inorganic N (NI), coupled with plants and full CN chemistry
DOC/NI PUNCTUATED DOC EXPERIMENT
The input was done on Apr.1st, Jun. 1st, Aug. 1st and Oct. 1st in the first model year. All simulations start with identical initial conditions.
Input DOC Input NH4Exp1 0.05 mol C 0
Exp2 5 mol C 0
Exp3 0.05 mol C 0.01 mol N
Exp4 5 mol C 1 mol N
CHANGE OF CUMULATIVE HETEROTROPHIC RESPIRATION
Exp 2Exp 1
Exp 3 Exp 4
Unit: mol CO2
PUNCTUATED DOC/NI EXPERIMENT
Exp 3 Exp 3
Exp 4 Exp 4
Changes in Microbial biomassUnit: mol C m-3 soil
Changes in litter degradationUnit: mol C m-3 soil s-1
0
0
DOC MOVEMENT EXPERIMENT
Microbial activity: fraction of active microbesImmobile: no vertical movement of DOC allowedMobile: DOC is free to move vertically
SUMMARY CLM4-BeTR is successfully developed for vertically
resolved biogeochemistry modeling Microbial dynamics is critical to improving the CN
modeling The priming effect depends on the dose of
substrate/nutrient input The vertical movement of DOC may provide a subtle
way to increase the carbon sequestration Measurements are need for serious model
evaluations (let me know if someone has measurements, we are open for collaborations!)
THE END?