Biome-scale response of land-atmosphere carbon exchange to long-lasting droughts

Authors: Xinyuan Wei*, University of Maine, Daniel J. Hayes, University of Maine
Topics: Environment, Biogeography
Keywords: carbon cycle, drought, terrestrial ecosystem
Session Type: Paper
Day: 4/6/2019
Start / End Time: 1:10 PM / 2:50 PM
Room: Forum Room, Omni, West
Presentation File: No File Uploaded


The global biosphere acts as a major sink for atmospheric carbon dioxide (CO2), mitigating the CO2 growth rate by taking up and storing carbon in vegetation biomass, soil organic matter, and other pools. Drought, an extreme natural event that occurs when the ecosystem water supply is significantly below the existing demand, can take place at regional- to continental- scales and over long time periods. Drought can greatly affect terrestrial biosphere carbon fluxes and storage through modifying both carbon uptake by photosynthesis and carbon release by ecosystem respiration, as well as by introducing time-lagged impacts such as fire, insect outbreak, and soil erosion. Worldwide, drought is becoming more frequent with increasing weather extremes, resulting in substantial impacts on land-atmosphere carbon exchange. Due to differences in adaptation and resilience among plant species, the response of carbon fluxes to drought is likely to vary among biomes. In this study, we integrated simulation results from an ensemble of terrestrial biosphere models and examined the spatial patterns of the biome relationship and response of carbon fluxes to drought at a 12-month temporal scale. The results suggest that, globally, terrestrial biosphere carbon fluxes are strongly correlated with drought extremes. Tropical regions have the most robust correlation, but tundra areas show the weakest. Overall, drought extremes promote the terrestrial ecosystem carbon release, however, drought extremes can accelerate the carbon sinks in some tundra and boreal regions.

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