Temperature Sensitivity in Individual Components of Ecosystem Respiration Increases along the Vertical Gradient of Leaf–Stem–Soil in Three Subtropical Forests

Temperature sensitivity (Q10) of ecosystem respiration (ER) is a crucial parameter for predicting the fate of CO2 in terrestrial e cosystems under global warming. Most studies focus their attention in the variation of Q10 in one or two components of ER, but not in the integration or comparison among Q10 in major components of ER. Vertical and seasonal variations in individual components, including leaf respiration, stem respiration and soil respiration, of ER were observed synchronously along the gradient of leaf–stem–soil over a 2 year period in three forest stands dominated by masson pine, loblolly pine and oak, respectively, in a subtropical forest ecosystem of central China. We found that Q10 in individual components of ER increased along the vertical gradient of leaf–stem–soil. The vertical pattern of Q10 in individual components of ER was ascribed to variations of diurnal temperature range (DTR) and activation energy (ΔHa). These results suggest that a vertical pattern of Q10 in individual components of ER along the gradient of leaf–stem–soil should be taken into consideration in process-based models that simulate respiratory carbon flux in terrestrial ecosystems.

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Impacts of droughts on carbon sequestration by China's terrestrial ecosystems from 2000 to 2011

Biogeosciences ◽

10.5194/bg-11-2583-2014 ◽

2014 ◽

Vol 11 (10) ◽

pp. 2583-2599 ◽

Cited By ~ 34

Author(s):

Y. Liu ◽

Y. Zhou ◽

W. Ju ◽

S. Wang ◽

X. Wu ◽

...

Keyword(s):

Carbon Sequestration ◽

Ecosystem Respiration ◽

Eastern China ◽

Terrestrial Ecosystems ◽

Northwest China ◽

Central China ◽

Ecosystem Productivity ◽

Model Driven ◽

Boreal Ecosystem ◽

Boreal Ecosystem Productivity Simulator

Abstract. In recent years, China's terrestrial ecosystems have experienced frequent droughts. How these droughts have affected carbon sequestration by the terrestrial ecosystems is still unclear. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model, driven by remotely sensed vegetation parameters, was employed to assess the effects of droughts on net ecosystem productivity (NEP) of terrestrial ecosystems in China from 2000 to 2011. Droughts of differing severity, as indicated by a standard precipitation index (SPI), hit terrestrial ecosystems in China extensively in 2001, 2006, 2009, and 2011. The national total annual NEP exhibited the slight decline of −11.3 Tg C yr−2 during the aforementioned years of extensive droughts. The NEP reduction ranged from 61.1 Tg C yr−1 to 168.8 Tg C yr−1. National and regional total NEP anomalies were correlated with the annual mean SPI, especially in Northwest China, North China, Central China, and Southwest China. The reductions in annual NEP in 2001 and 2011 might have been caused by a larger decrease in annual gross primary productivity (GPP) than in annual ecosystem respiration (ER). The reductions experienced in 2009 might be due to a decrease in annual GPP and an increase in annual ER, while reductions in 2006 could stem from a larger increase in ER than in GPP. The effects of droughts on NEP lagged up to 3–6 months, due to different responses of GPP and ER. In eastern China, where is humid and warm, droughts have predominant and short-term lagged influences on NEP. In western regions, cold and arid, the drought effects on NEP were relatively weaker but prone to lasting longer.

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A temperature threshold to identify the driving climate forces of the respiratory process in terrestrial ecosystems

10.5194/bg-2017-345 ◽

2017 ◽

Author(s):

Zhiyuan Zhang ◽

Renduo Zhang ◽

Yang Zhou ◽

Alessandro Cescatti ◽

Georg Wohlfahrt ◽

...

Keyword(s):

Air Temperature ◽

Driving Forces ◽

Ecosystem Respiration ◽

Large Fraction ◽

Terrestrial Ecosystem ◽

Terrestrial Ecosystems ◽

Co2 Concentration ◽

Temperature Threshold ◽

Current Scenario ◽

Ecosystem Flux

Abstract. Terrestrial ecosystem respiration (Re) is the major source of CO2 release and constitutes the second largest carbon flux between the biosphere and atmosphere. Therefore, climate-driven changes of Re may greatly impact on future atmospheric CO2 concentration. The aim of this study was to derive an air temperature threshold for identifying the driving climate forces of the respiratory process in terrestrial ecosystems within different temperature zones. For this purpose, a global dataset of 647 site-years of ecosystem flux data collected at 152 sites has been examined. Our analysis revealed an ecosystem threshold of mean annual air temperature (MAT) of 11 &pm; 2.3 °C. In ecosystems with the MAT below this threshold, the maximum Re rates were primarily dependent on temperature and respiration was mainly a temperature-driven process. On the contrary, in ecosystems with the MAT greater than 11 ± 2.3 °C, in addition to temperature, other driving forces, such as water availability and surface heat flux, became significant drivers of the maximum Re rates and respiration was a multi-factor-driven process. The information derived from this study highlight the key role of temperature as main controlling factor of the maximum Re rates on a large fraction of the terrestrial biosphere, while other driving forces reduce the maximum Re rates and temperature sensitivity of the respiratory process. These findings are particularly relevant under the current scenario of rapid global warming, given that the potential climate-induced changes in ecosystem respiration may lead to substantial anomalies in the seasonality and magnitude of the terrestrial carbon budget.

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Chapter Eighteen Uncertainty and Sensitivity Issues in Process-based Models of Carbon and Nitrogen Cycles in Terrestrial Ecosystems

Environmental Modelling, Software and Decision Support - Developments in Integrated Environmental Assessment ◽

10.1016/s1574-101x(08)00618-2 ◽

2008 ◽

pp. 307-327 ◽

Cited By ~ 9

Author(s):

G.R. Larocque ◽

J.S. Bhatti ◽

A.M. Gordon ◽

N. Luckai ◽

M. Wattenbach ◽

...

Keyword(s):

Terrestrial Ecosystems ◽

Carbon And Nitrogen ◽

Nitrogen Cycles ◽

Process Based Models

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Elevated CO2does not affect stem CO2efflux nor stem respiration in a dryEucalyptuswoodland, but it shifts the vertical gradient in xylem [CO2]

Plant Cell & Environment ◽

10.1111/pce.13550 ◽

2019 ◽

Vol 42 (7) ◽

pp. 2151-2164 ◽

Cited By ~ 4

Author(s):

Roberto L. Salomón ◽

Kathy Steppe ◽

Kristine Y. Crous ◽

Nam Jin Noh ◽

David S. Ellsworth

Keyword(s):

Vertical Gradient ◽

Stem Respiration

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Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

Journal of Plant Ecology ◽

10.1093/jpe/rtu014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 419-428 ◽

Cited By ~ 7

Author(s):

Bing Song ◽

Shuli Niu ◽

Ruisen Luo ◽

Yiqi Luo ◽

Jiquan Chen ◽

...

Keyword(s):

Temperature Sensitivity ◽

Ecosystem Respiration ◽

Terrestrial Ecosystem ◽

Apparent Temperature

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Soil Organic Carbon Mineralization and its Temperature Sensitivity Along a Vegetation Restoration Gradient in Subtropical China

10.21203/rs.3.rs-707985/v1 ◽

2021 ◽

Author(s):

Xiong Fang ◽

Haozhao Sun ◽

Yunpeng Huang ◽

Jundi Liu ◽

Yulin Zhu ◽

...

Keyword(s):

Soil Moisture ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Temperature Sensitivity ◽

Interactive Effect ◽

Carbon Mineralization ◽

Terrestrial Ecosystems ◽

Vegetation Restoration ◽

Soil Organic Carbon Mineralization ◽

Soc Mineralization

Abstract Background and aims Soil organic carbon (SOC) mineralization produces important CO2 flux from terrestrial ecosystems which can provide feedbacks to climates. Vegetation restoration can affect SOC mineralization and its temperature sensitivity (Q10), but how this effect is related to soil moisture remains uncertain. Methods We performed a laboratory incubation using soils of different vegetation restoration stages (i.e., degraded vegetation [DS], plantation [PS], and secondary natural forest [SFS]) maintained under different moisture and temperature conditions to explore the combined effects of vegetation restoration and soil moisture on SOC mineralization and Q10. Results We found that cumulative SOC mineralization in PS and SFS were about 11.7 times higher than that in the DS, associated with higher SOC content and microbial biomass. Increased soil moisture and temperature led to higher SOC mineralization in the SFS and PS. However, in the DS, soil moisture did not affect SOC mineralization, but temperature enhancement solely increased (158.7%) SOC mineralization at the 60%MWHC treatment. Furthermore, significant interactive effect of vegetation restoration and soil moisture on Q10 was detected. At the 60%MWHC treatment, Q10 declined with vegetation restoration age. Nevertheless, at the 30%MWHC treatment, Q10 was lower in the DS than that in the PS. Higher soil moisture did not affect Q10 in the PS and SFS, but enhanced Q10 in the DS. Conclusions Our results highlight that the responses of SOC mineralization and Q10 to vegetation restoration were highly dependent on soil moisture and substrate availability, and vegetation restoration reduced the influence of soil moisture on Q10.

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Recent Warming Has Resulted in Smaller Gains in Net Carbon Uptake in Northern High Latitudes

Journal of Climate ◽

10.1175/jcli-d-18-0653.1 ◽

2019 ◽

Vol 32 (18) ◽

pp. 5849-5863 ◽

Cited By ~ 1

Author(s):

Peng Zhu ◽

Qianlai Zhuang ◽

Lisa Welp ◽

Philippe Ciais ◽

Martin Heimann ◽

...

Keyword(s):

Temperature Sensitivity ◽

Carbon Balance ◽

Climate Models ◽

Carbon Sink ◽

Gross Primary Production ◽

Terrestrial Ecosystems ◽

Atmospheric Co2 ◽

Climate Feedback ◽

Carbon Uptake ◽

High Latitudes

AbstractCarbon balance of terrestrial ecosystems in the northern high latitudes (NHL) is sensitive to climate change. It remains uncertain whether current regional carbon uptake capacity can be sustained under future warming. Here the atmospheric CO2 drawdown rate (CDR) between 1974 and 2014, defined as the CO2 decrease in ppm over the number of days in spring or summer, is estimated using atmospheric CO2 observations at Barrow (now known as Utqiaġvik), Alaska. We found that the sensitivity of CDR to interannual seasonal air temperature anomalies has trended toward less carbon uptake for a given amount of warming over this period. Changes in interannual temperature sensitivity of CDR suggest that relatively warm springs now result in less of a carbon uptake enhancement. Similarly, relatively warm summers now result in greater carbon release. These results generally agree with the sensitivity of net carbon exchange (NCE) estimated by atmospheric CO2 inversion. When NCE was aggregated over North America (NA) and Eurasia (EA), separately, the temperature sensitivity of NCE in NA has changed more than in EA. To explore potential mechanisms of this signal, we also examine trends in interannual variability of other climate variables (soil temperature and precipitation), satellite-derived gross primary production (GPP), and Trends in Net Land–Atmosphere Carbon Exchanges (TRENDY) model ensemble results. Our analysis suggests that the weakened spring sensitivity of CDR may be related to the slowdown in seasonal soil thawing rate, while the summer sensitivity change may be caused by the temporally coincident decrease in temperature sensitivity of photosynthesis. This study suggests that the current NHL carbon sink may become unsustainable as temperatures warm further. We also found that current carbon cycle models do not represent the decrease in temperature sensitivity of net carbon flux. We argue that current carbon–climate models misrepresent important aspect of the carbon–climate feedback and bias the estimation of warming influence on NHL carbon balance.

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