Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

Warming-induced carbon loss through terrestrial ecosystem respiration (Re) is likely getting stronger in high latitudes and cold regions because of the more rapid warming and higher temperature sensitivity of Re (Q10). However, it is not known whether the spatial relationship between Q10 and temperature also holds temporally under a future warmer climate. Here, we analyzed apparent Q10 values derived from multiyear observations at 74 FLUXNET sites spanning diverse climates and biomes. We found warming-induced decline in Q10 is stronger at colder regions than other locations, which is consistent with a meta-analysis of 54 field warming experiments across the globe. We predict future warming will shrink the global variability of Q10 values to an average of 1.44 across the globe under a high emission trajectory (RCP 8.5) by the end of the century. Therefore, warming-induced carbon loss may be less than previously assumed because of Q10 homogenization in a warming world.

Download Full-text

Global consistency in response of terrestrial ecosystem respiration to temperature

10.5194/egusphere-egu21-9690 ◽

2021 ◽

Author(s):

Huanyuan Zhang ◽

Zhiyuan Zhang ◽

Zikun Cui ◽

Feng Tao ◽

Ziwei Chen ◽

...

Keyword(s):

Temperature Sensitivity ◽

Ecosystem Respiration ◽

Spatial Scales ◽

Terrestrial Ecosystem ◽

Mean Annual Temperature ◽

Global Consistency ◽

S Curve ◽

Warming World ◽

The Relationship ◽

Sigmoid Functions

Many studies have been carried out to quantify the trend of terrestrial ecosystem respiration (Re) in a warming world, but a conclusive answer has not yet been confirmed because the temperature sensitivity of Re was found inconsistent under different scales or regarding different types of respiratory flux. &#160;Aiming at clarifying the relationship between temperature and Re across different scales, we proposed a method to counteract the confounding effect and applied nine empirical models to a 1,387 site-years FLUXNET dataset.&#160; Regarding the temperature sensitivity of half-hourly Re records, we found a surprisingly consistent result that the sigmoid functions outcompeted other statistical models in almost all datasets (account for 82%), and on average, achieved a staggering R2 value of 0.92, indicating the positive correlation between Re and temperature on fine time scale (within one site-year dataset). &#160;Even though Re of all biomes followed sigmoid functions, the parameters of the S-curve varied strongly across sites. &#160;This explains why measured Q10 value (an index denote temperature sensitivity) largely depends on observation season and site. &#160;Furthermore, on the interannual variation of Re, we did not find any relationship between mean annual temperature (MAT) and mean annual Re within any site, which implies that the small year-to-year variation of the sigmoid pattern is large enough to counteract the warming effect on Re. &#160;This study thereby put forward a conceptual model to integrate the relationship between temperature and Re under different scales. It also provided evidences to support the argument that the relationship between MAT and mean annual Re (i.e., respiration under global warming) should not be inferred from studies on other temporal or spatial scales.

Download Full-text

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.

Download Full-text

Bulk partitioning the growing season net ecosystem exchange of CO2 in Siberian tundra reveals the seasonality of its carbon sequestration strength

Biogeosciences Discussions ◽

10.5194/bgd-9-13713-2012 ◽

2012 ◽

Vol 9 (10) ◽

pp. 13713-13742 ◽

Cited By ~ 3

Author(s):

B. R. K. Runkle ◽

T. Sachs ◽

C. Wille ◽

E.-M. Pfeiffer ◽

L. Kutzbach

Keyword(s):

Carbon Sink ◽

Ecosystem Respiration ◽

Growing Season ◽

New Method ◽

Apparent Temperature ◽

The Arctic ◽

Co2 Uptake ◽

Night Time ◽

Tundra Ecosystem ◽

Co2 Sink

Abstract. This paper evaluates the relative contribution of light and temperature on net ecosystem CO2 uptake during the 2006 growing season in a~polygonal tundra ecosystem in the Lena River Delta in Northern Siberia (72°22´ N, 126°30´ E). We demonstrate that the timing of warm periods may be an important determinant of the magnitude of the ecosystem's carbon sink function, as they drive temperature-induced changes in respiration. Hot spells during the early portion of the growing season are shown to be more influential in creating mid-day surface-to-atmosphere net ecosystem CO2 exchange fluxes than those occurring later in the season. In this work we also develop and present a bulk flux partition model to better account for tundra plant physiology and the specific light conditions of the arctic region that preclude the successful use of traditional partition methods that derive a respiration-temperature relationship from all night-time data. Night-time, growing season measurements are rare during the arctic summer, however, so the new method allows for temporal variation in the parameters describing both ecosystem respiration and gross uptake by fitting both processes at the same time. Much of the apparent temperature sensitivity of respiration seen in the traditional partition method is revealed in the new method to reflect seasonal changes in basal respiration rates. Understanding and quantifying the flux partition is an essential precursor to describing links between assimilation and respiration at different time scales, as it allows a more confident evaluation of measured net exchange over a broader range of environmental conditions. The growing season CO2 sink estimated by this study is similar to those reported previously for this site, and is substantial enough to withstand the long, low-level respiratory CO2 release during the rest of the year to maintain the site's CO2 sink function on an annual basis.

Download Full-text

Towards a standardized processing of Net Ecosystem Exchange measured with eddy covariance technique: algorithms and uncertainty estimation

Biogeosciences ◽

10.5194/bg-3-571-2006 ◽

2006 ◽

Vol 3 (4) ◽

pp. 571-583 ◽

Cited By ~ 866

Author(s):

D. Papale ◽

M. Reichstein ◽

M. Aubinet ◽

E. Canfora ◽

C. Bernhofer ◽

...

Keyword(s):

Eddy Covariance ◽

Ecosystem Respiration ◽

Gross Primary Production ◽

Net Ecosystem Exchange ◽

Terrestrial Ecosystem ◽

Climatic Conditions ◽

High Temporal Resolution ◽

Eddy Covariance Technique ◽

Forest Sites ◽

European Database

Abstract. Eddy covariance technique to measure CO2, water and energy fluxes between biosphere and atmosphere is widely spread and used in various regional networks. Currently more than 250 eddy covariance sites are active around the world measuring carbon exchange at high temporal resolution for different biomes and climatic conditions. In this paper a new standardized set of corrections is introduced and the uncertainties associated with these corrections are assessed for eight different forest sites in Europe with a total of 12 yearly datasets. The uncertainties introduced on the two components GPP (Gross Primary Production) and TER (Terrestrial Ecosystem Respiration) are also discussed and a quantitative analysis presented. Through a factorial analysis we find that generally, uncertainties by different corrections are additive without interactions and that the heuristic u*-correction introduces the largest uncertainty. The results show that a standardized data processing is needed for an effective comparison across biomes and for underpinning inter-annual variability. The methodology presented in this paper has also been integrated in the European database of the eddy covariance measurements.

Download Full-text

On quantifying the apparent temperature sensitivity of plant phenology

New Phytologist ◽

10.1111/nph.16114 ◽

2019 ◽

Vol 225 (2) ◽

pp. 1033-1040 ◽

Cited By ~ 7

Author(s):

Trevor F. Keenan ◽

Andrew D. Richardson ◽

Koen Hufkens

Keyword(s):

Temperature Sensitivity ◽

Plant Phenology ◽

Apparent Temperature

Download Full-text

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

Forests ◽

10.3390/f11020140 ◽

2020 ◽

Vol 11 (2) ◽

pp. 140

Author(s):

Yonggang Chi ◽

Qingpeng Yang ◽

Lei Zhou ◽

Ruichang Shen ◽

Shuxia Zheng ◽

...

Keyword(s):

Loblolly Pine ◽

Temperature Sensitivity ◽

Ecosystem Respiration ◽

Terrestrial Ecosystems ◽

Vertical Gradient ◽

Central China ◽

Masson Pine ◽

Stem Respiration ◽

Crucial Parameter ◽

Process Based Models

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.

Download Full-text

McGill wetland model: evaluation of a peatland carbon simulator developed for global assessments

Biogeosciences ◽

10.5194/bg-7-3517-2010 ◽

2010 ◽

Vol 7 (11) ◽

pp. 3517-3530 ◽

Cited By ~ 65

Author(s):

F. St-Hilaire ◽

J. Wu ◽

N. T. Roulet ◽

S. Frolking ◽

P. M. Lafleur ◽

...

Keyword(s):

Water Table ◽

Ecosystem Respiration ◽

Gross Primary Production ◽

General Structure ◽

Terrestrial Ecosystem ◽

Ecosystem Model ◽

Terrestrial Ecosystem Model ◽

Use Efficiency ◽

One Year ◽

Anoxic Zones

Abstract. We developed the McGill Wetland Model (MWM) based on the general structure of the Peatland Carbon Simulator (PCARS) and the Canadian Terrestrial Ecosystem Model. Three major changes were made to PCARS: (1) the light use efficiency model of photosynthesis was replaced with a biogeochemical description of photosynthesis; (2) the description of autotrophic respiration was changed to be consistent with the formulation of photosynthesis; and (3) the cohort, multilayer soil respiration model was changed to a simple one box peat decomposition model divided into an oxic and anoxic zones by an effective water table, and a one-year residence time litter pool. MWM was then evaluated by comparing its output to the estimates of net ecosystem production (NEP), gross primary production (GPP) and ecosystem respiration (ER) from 8 years of continuous measurements at the Mer Bleue peatland, a raised ombrotrophic bog located in southern Ontario, Canada (index of agreement [dimensionless]: NEP = 0.80, GPP = 0.97, ER = 0.97; systematic RMSE [g C m−2 d−1]: NEP = 0.12, GPP = 0.07, ER = 0.14; unsystematic RMSE: NEP = 0.15, GPP = 0.27, ER = 0.23). Simulated moss NPP approximates what would be expected for a bog peatland, but shrub NPP appears to be underestimated. Sensitivity analysis revealed that the model output did not change greatly due to variations in water table because of offsetting responses in production and respiration, but that even a modest temperature increase could lead to converting the bog from a sink to a source of CO2. General weaknesses and further developments of MWM are discussed.

Download Full-text