Interannual and seasonal variations in carbon exchanges over an alpine meadow in the northeastern edge of the Qinghai-Tibet Plateau, China.

Jinkui Wu,Hongyuan Li,Yongjian Ding,Di Zeng,Hao Wu,Shiwei Liu,Jia Qin,Dafeng Hui

doi:10.1371/journal.pone.0228470

Jinkui Wu, Hongyuan Li + Show 6 more

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https://doi.org/10.1371/journal.pone.0228470

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Abstract

The alpine meadow is highly sensitive to global climate change due to its high elevation and cold environment. To understand the dynamics of ecosystem carbon cycling, CO2 fluxes were measured over the Suli alpine meadow, which is located at the upper reach of the Shule River basin at the northeastern edge of the Qinghai-Tibet Plateau (QTP), China. The measurements were taken from October 2008 to September 2012 using the eddy covariance technique. Obvious seasonal and inter-annual variations were observed in the CO2 flux. The annual net carbon exchange ranged from -195.28 g·CO2·m-2 to -118.49 g·CO2·m-2, indicating that the alpine meadow ecosystem in this area played a role as a carbon sink. The inter-annual variability in the net carbon exchange was significantly related to the length of the growing season for the alpine meadow. The results showed that the months of June, July and August were the strongest CO2 absorption periods, while April, May and October were the strongest CO2 release periods. The annual net exchanges of CO2 in the four years were -118.49 g·CO2·m-2, -130.75 g·CO2·m-2, -195.83 g·CO2·m-2 and -160.65 g·CO2·m-2, and the average value was -151.43 g·CO2·m-2. On a seasonal scale, the monthly CO2 fluxes were largely controlled by temperature. At the annual scale, there was no dominant factor that influenced the interannual variations in the CO2 flux.

Highlights

Accurate evaluations of the carbon dioxide (CO2) flux in different ecosystems can help deepen and improve our understanding of land-atmosphere interactions and enhance the decisionmaking abilities of climate policymakers [1, 2]
Some studies have examined the CO2 fluxes of alpine meadow, alpine shrub-meadow, and alpine wetland meadow based on eddy covariance (EC) measurements on the Tibetan Plateau [8, 17, 44,45,46,47,48,49,50,51] and revealed that some sites were sinks of atmospheric CO2 [9, 18, 44,45,46,47,48,49,50], while others were CO2 sources on an annual scale [18, 51]
Source This study Kato et al, 2006 Fu et al, 2009 Zhao et al, 2010 Li et al, 2016 Zhang., 2012 Fu et al, 2009 Wang et al, 2014 Zhang., 2017 Zhu et al, 2015 Wu et al, 2010 Wang, 2015 obtained in the present study showed that the alpine meadow ecosystems in Suli were carbon sinks in the growing season and carbon sources in the non-growing season

Summary

Introduction

Accurate evaluations of the carbon dioxide (CO2) flux in different ecosystems can help deepen and improve our understanding of land-atmosphere interactions and enhance the decisionmaking abilities of climate policymakers [1, 2]. The evaluation of the global CO2 flux in an ecosystem requires the construction and validation of carbon cycle models in the major. Carbon exchanges over an alpine meadow in northeastern edge Qinghai-Tibet Plateau collection and analysis, decision to publish, or preparation of the manuscript

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