Soil CO2concentrations and emissions from tropical forests are modulated seasonally by precipitation. However, subseasonal responses to meteorological events (e.g., storms, drought) are less well known. Here, we present the effects of meteorological variability on short‐term (hours to months) dynamics of soil CO2concentrations and emissions in a Neotropical wet forest. We continuously monitored soil temperature, moisture, and CO2for a three‐year period (2015–2017), encompassing normal conditions, floods, a dry El Niño period, and a hurricane. We used a coupled model (Hydrus‐1D) for soil water propagation, heat transfer, and diffusive gas transport to explain observed soil moisture, soil temperature, and soil CO2concentration responses to meteorology, and we estimated soil CO2efflux with a gradient‐flux model. Then, we predicted changes in soil CO2concentrations and emissions under different warming climate change scenarios. Observed short‐term (hourly to daily) soil CO2concentration responded more to precipitation than to other meteorological variables (including lower pressure during the hurricane). Observed soil CO2failed to exhibit diel patterns (associated with diel temperature fluctuations in drier climates), except during the drier El Niño period. Climate change scenarios showed enhanced soil CO2due to warmer conditions, while precipitation played a critical role in moderating the balance between concentrations and emissions. The scenario with increased precipitation (based on a regional model projection) led to increases of +11% in soil CO2concentrations and +4% in soil CO2emissions. The scenario with decreased precipitation (based on global circulation model projections) resulted in increases of +4% in soil CO2concentrations and +18% in soil CO2emissions, and presented more prominent hot moments in soil CO2outgassing. These findings suggest that soil CO2will increase under warmer climate in tropical wet forests, and precipitation patterns will define the intensity of CO2outgassing hot moments.
- Award ID(s):
- 1831952
- NSF-PAR ID:
- 10304273
- Date Published:
- Journal Name:
- Biogeosciences
- Volume:
- 18
- Issue:
- 5
- ISSN:
- 1726-4189
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Synthesis . The effects of fine‐scale topographic heterogeneity on tropical forest structure and composition depend on the climate context. Our study demonstrates how a stronger integration of topographic heterogeneity across precipitation gradients could improve estimates of forest structure and biomass, and may provide insight to the ways that topography might mediate species responses to drought and climate change.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.5194/bg-18-1769-2021
