Title: Impact of Shifts in Vegetation Phenology on the Carbon Balance of a Semiarid Sagebrush Ecosystem

Abstract

Dryland ecosystems are critical in regulating the interannual variability of the global terrestrial carbon cycle. The responses of such ecosystems to weather and environmental conditions remain important factors that limit the accurate projections of carbon balance under future climate change. Here, we investigated how shifts in vegetation phenology resulting from changes in weather and environmental conditions influenced ecosystem carbon cycling in one semiarid ecosystem in the Hanford area of central Washington, United States. We examined two years of measurements of the phenology camera, eddy covariance, and soil chamber from an upland semiarid sagebrush ecosystem. Both years had contrasting diel and seasonal patterns of CO₂ fluxes, primarily driven by differences in vegetation phenology. The net ecosystem exchange of CO₂ (NEE) and evapotranspiration (ET) in 2019 were enlarged by shifted vegetation phenology, as a cold and snow-covered winter and warm and dry winter in 2020 resulted in constrained magnitudes of NEE and ET during the summer months. The annual gross primary productivity (GPP) was much higher in 2019 than in 2020 (-211 vs. -112 gC m^-2), whereas ecosystem respiration was comparable in these two years (164 vs. 144 gC m^-2). Thus, the annual NEE in 2019 was negative (-47 gC m^-2) withmore » the sagebrush ecosystem functioning as a carbon sink, while the positive annual NEE in 2020 indicated that the sagebrush ecosystem functioned as a carbon source. Our results demonstrate that winter snowpack can be a critical driver of annual carbon uptake in semiarid sagebrush ecosystems.« less

Authors:

Yao, Jingyu ^[1]; Yuan, Wenping ^[1]; Gao, Zhongming  ^[1];

• Search DOE PAGES for author "Gao, Zhongming"
• Search DOE PAGES for ORCID "0000-0002-4390-753X"

Liu, Heping ^[2]; Chen, Xingyuan ^[3]; Ma, Yongjing  ^[4];

• Search DOE PAGES for author "Ma, Yongjing"
• Search DOE PAGES for ORCID "0000-0003-1104-7165"

Arntzen, Evan V.  ^[3];

• Search DOE PAGES for author "Arntzen, Evan V."
• Search DOE PAGES for ORCID "0000-0002-9209-5670"

Mcfarland, Douglas P. ^[3]

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+ Show Author Affiliations

1. Sun Yat-Sen Univ. (China)
2. Washington State Univ., Pullman, WA (United States)
3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
4. Chinese Academy of Sciences (CAS), Beijing (China)

Publication Date:

Wed Nov 23 00:00:00 EST 2022

Research Org.:

Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER); National Natural Science Foundation of China (NSFC); China National Postdoctoral Program for Innovative Talents; Fundamental Research Funds for the Central Universities

OSTI Identifier:

1902127

Report Number(s):

PNNL-SA-179255
Journal ID: ISSN 2072-4292

Grant/Contract Number:  

AC05-76RL01830; 41925001; BX20220366; 22qntd1911

Resource Type:

Accepted Manuscript

Journal Name:

Remote Sensing

Additional Journal Information:

Journal Volume: 14; Journal Issue: 23; Journal ID: ISSN 2072-4292

Publisher:

MDPI

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; carbon fluxes; PhenoCam; semi-arid regions; snowpack; vegetation phenology