Table 3 Comparative roles of soil moisture in carbon sequestration and greenhouse gas emissions across selected ecosystem models

Biome-BGC

• Impacts drought stress levels, which in turn affect net primary productivity and carbon uptake.

• Indirectly represented through its impact on plant-mediated CO₂ fluxes.

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BEPS-TerrainLab V2.0

• Affects plant photosynthesis and microbial decomposition

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CoLM

• Affects stomatal conductance, which in turn influences photosynthesis and carbon uptake.

• Impacts CO₂ release through both autotrophic (plant-related) and heterotrophic (microbial-related) respiration rates.

• Regulates CO₂ emissions from nutrient mineralization and decomposition processes, as controlled by soil moisture levels.

• The vegetation dynamics component includes fire parameterizations that respond to soil moisture and litter availability. Reduced soil moisture elevates fire occurrence probabilities, resulting in CO₂ release.

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ORCHIDEE

• Incorporates water stress factors into photosynthesis parameterizations

• Influences the allocation of carbon to different plant tissues

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LPJ-GUESS

• Influences photosynthesis, carbon allocation and vegetation dynamics

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DLEM

• Influences plant photosynthesis and respiration, affecting carbon uptake and storage in biomass.

• Acts as a connecting variable among model components, impacting overall carbon cycling processes in the ecosystem.

• Modulates CO₂ release through plant photosynthesis, soil respiration, and microbial decomposition.

• Affects CH₄ dynamics by promoting methanogenesis in saturated, anaerobic conditions and enhancing CH₄ oxidation in drier, aerobic soils.

• Influences N₂O emissions by facilitating nitrification under optimal aerobic conditions and enhancing denitrification in high-moisture, anaerobic environments.

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DNDC

• Tracks physiological processes, such as water stress and nutrient uptake.

• Track daily soil moisture content, which directly affects respiration rates and, consequently, CO₂ fluxes.

• Simulates CH₄ fluxes under varying hydrological conditions.

• Simulates N₂O and N₂ emissions based on soil moisture and redox potential, influenced by the ‘anaerobic balloon’ concept that models simultaneous aerobic and anaerobic microsites.

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CLM5

• By maintaining healthy vegetation through improved plant hydraulics, soil moisture directly and indirectly supports carbon sequestration and storage in terrestrial ecosystems.

• Influences plant photosynthesis, soil respiration, microbial decomposition and fire susceptibility, thereby affecting CO₂ emissions through both vegetation stress and combustion processes.

• High soil moisture levels in wetlands create anaerobic conditions essential for CH₄ production

• Affects nitrification and denitrification processes, facilitating N₂O production and emissions

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ELM

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