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Published on: June 24, 2019
Coupling between carbon cycling and climate in a high-elevation, subalpine forest: a model-data fusion analysis
William J Sacks1, David S Schimel, Russell K Monson
1Center for Sustainability and the Global Environment, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, 1710 University Avenue, Madison, WI 53726, USA. wsacks@wisc.edu
Oecologia
|October 3, 2006
Summary
Climate significantly impacts terrestrial carbon exchange. Longer growing seasons can decrease CO2 uptake due to water limitations, while warmer springs increase uptake only with sufficient moisture.
Area of Science:
- Ecology
- Climate Science
- Biogeochemistry
Background:
- Terrestrial ecosystems play a crucial role in regulating atmospheric CO2. Understanding climate's influence on carbon cycling is vital for predicting future climate change.
- Net ecosystem CO2 exchange (NEE) is a key metric, but its components require further investigation to understand ecosystem responses to climate variability.
Purpose of the Study:
- To partition NEE into gross ecosystem CO2 exchange (GEE) and ecosystem respiration (RE) to analyze their climate-driven variability.
- To investigate the sub-components of ecosystem respiration (RE), specifically heterotrophic (RH) and autotrophic (RA) respiration.
- To assess the impact of climate factors on carbon fluxes at the Niwot Ridge AmeriFlux site.
Main Methods:
- Utilized an ecosystem process model integrated with 6 years of flux data from the Niwot Ridge AmeriFlux site.
- Separated observed NEE into GEE and RE using model-data fusion techniques.
- Attempted to partition RE into RH and RA, but faced challenges due to data limitations.
Main Results:
- Successfully separated GEE and RE, revealing that GEE variability drives most of the interannual NEE fluctuations.
- Found that longer growing seasons correlated with reduced net CO2 uptake due to late-season water scarcity.
- Observed that warmer spring temperatures enhanced CO2 uptake only when moisture was adequate, otherwise leading to reduced annual uptake.
Conclusions:
- Interannual NEE variability at Niwot Ridge is primarily driven by changes in GEE, not RE.
- Climate-water interactions, particularly snowmelt dynamics and spring moisture availability, critically influence the carbon balance of this ecosystem.
- Accurate partitioning of RE into RH and RA requires more distinct data contrasts than were available in this study.
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