Supplementary material to "Ecosystem carbon transit versus turnover times in response to climate warming and rising atmospheric CO2 concentration"

Abstract. Ecosystem carbon (C) transit time is a critical diagnostic parameter to characterize land C sequestration. This parameter has different variants in the literature, including a commonly used turnover time. However, we know little about how different transit time and turnover time are in representing carbon cycling through multiple compartments under a non-steady state. In this study, we estimate both C turnover time as defined by the conventional stock over flux and mean C transit time as defined by the mean age of C mass leaving the system. We incorporate them into the Community Atmosphere Biosphere Land Exchange (CABLE) model to estimate C turnover time and transit time in response to climate warming and rising atmospheric [CO2]. Modelling analysis shows that both C turnover time and transit time increase with climate warming but decrease with rising atmospheric [CO2]. Warming increases C turnover time by 2.4 years and transit time by 11.8 years in 2100 relative to that at steady state in 1901. During the same period, rising atmospheric [CO2] decreases C turnover time by 3.8 years and transit time by 5.5 years. Our analysis shows that 65 % of the increase in global mean C transit time with climate warming results from the depletion of fast-turnover C pool. The remaining 35 % increase results from accompanied changes in compartment C age structures. Similarly, the decrease in mean C transit time with rising atmospheric [CO2] results approximately equally from replenishment of C into fast-turnover C pool and subsequent decrease in compartment C age structure. Greatly different from the transit time, the turnover time, which does not account for changes in either C age structure or composition of respired C, underestimated impacts of warming and rising atmospheric [CO2] on C diagnostic time and potentially led to deviations in estimating land C sequestration in multi-compartmental ecosystems.

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Supplementary material to "Simulating climate warming scenarios with intentionally biased bootstrapping and its implications for precipitation"

10.5194/gmd-2016-188-supplement ◽

2016 ◽

Author(s):

Taesam Lee

Keyword(s):

Climate Warming ◽

Supplementary Material

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Supplementary material to "Simulating measurable ecosystem carbon and nitrogen dynamics with the mechanistically-defined MEMS 2.0 model"

10.5194/bg-2020-493-supplement ◽

2021 ◽

Author(s):

Yao Zhang ◽

Jocelyn M. Lavallee ◽

Andy D. Robertson ◽

Rebecca Even ◽

Stephen M. Ogle ◽

...

Keyword(s):

Nitrogen Dynamics ◽

Carbon And Nitrogen ◽

Ecosystem Carbon ◽

Carbon And Nitrogen Dynamics ◽

Supplementary Material

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Experimental warming increases ecosystem respiration by increasing above-ground respiration in alpine meadows of Western Himalaya

Scientific Reports ◽

10.1038/s41598-021-82065-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Pankaj Tiwari ◽

Pamela Bhattacharya ◽

Gopal Singh Rawat ◽

Ishwari Datt Rai ◽

Gautam Talukdar

Keyword(s):

Climate Warming ◽

Ecosystem Respiration ◽

Western Himalaya ◽

Experimental Warming ◽

Alpine Ecosystems ◽

Alpine Meadows ◽

Respiration Rates ◽

Ecosystem Carbon ◽

Plant Respiration ◽

The Himalaya

AbstractAlpine ecosystems in the Himalaya, despite low primary productivity, store considerable amount of organic carbon. However, these ecosystems are highly vulnerable to climate warming which may stimulate ecosystem carbon efflux leading to carbon-loss and positive feedback. We used open-top chambers to understand warming responses of ecosystem respiration (ER) and soil respiration (SR) in two types of alpine meadows viz., herbaceous meadow (HM) and sedge meadow (SM), in the Western Himalaya. Experimental warming increased ER by 33% and 28% at HM and SM, respectively. No significant effect on SR was observed under warming, suggesting that the increase in ER was primarily due to an increase in above-ground respiration. This was supported by the warming-induced increase in above-ground biomass and decrease in SR/ER ratio. Soil temperature was the dominant controlling factor of respiration rates and temperature sensitivity of both ER and SR increased under warming, indicating an increase in contribution from plant respiration. The findings of the study suggest that climate warming by 1.5–2 °C would promote ER via increase in above-ground respiration during the growing season. Moreover, net C uptake in the alpine meadows may increase due to enhanced plant growth and relatively resistant SR under warming.

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Supplementary material to "Variations in diurnal and seasonal net ecosystem carbon dioxide exchange in a semiarid sandy grassland ecosystem in China's Horqin Sandy Land"

10.5194/bg-2020-89-supplement ◽

2020 ◽

Author(s):

Yayi Niu ◽

Yuqiang Li ◽

Hanbo Yun ◽

Xuyang Wang ◽

Xiangwen Gong ◽

...

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Exchange ◽

Horqin Sandy Land ◽

Sandy Land ◽

Grassland Ecosystem ◽

Ecosystem Carbon ◽

Supplementary Material ◽

Sandy Grassland

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Ecosystem carbon transit versus turnover times in response to climate warming and rising atmospheric CO2 concentration

10.5194/bg-2018-175 ◽

2018 ◽

Author(s):

Xingjie Lu ◽

Ying-Ping Wang ◽

Yiqi Luo ◽

Lifen Jiang

Keyword(s):

Transit Time ◽

Climate Warming ◽

Age Structure ◽

C Sequestration ◽

Turnover Time ◽

Atmospheric Co2 ◽

Ecosystem Carbon ◽

Subsequent Decrease ◽

Modeling Analysis ◽

Diagnostic Time

Abstract. Ecosystem carbon (C) transit time is a critical diagnostic parameter to characterize land C sequestration. This parameter has different variants in literatures, including a commonly used turnover time. However, neither of them has been carefully examined under transient C dynamics in response to climate change. In this study, we estimated both C turnover time as defined by the conventional stock-over-flux (i.e., Olson method) and mean C transit time as defined by the mean age of C mass leaving the system (i.e., Rasmussen method). We incorporated them into Community Atmosphere-Biosphere-Land Exchange model (CABLE) to estimate C turnover time and transit time, respectively, in response to climate warming and rising atmospheric [CO2]. Modeling analysis showed that both C turnover time and transit time increased with climate warming but decreased with rising atmospheric [CO2]. The increase of C turnover time with warming was estimated to be 2.4 years with Olson method whereas the transit time increased by 11.8 years with Rasmussen method. The decrease with rising atmospheric [CO2] was estimated to be 3.8 years with Olson method and 5.5 years with Rasmussen method. Our analysis based on Rasmussen method showed that 65 % of the increase in global mean C transit time with climate warming results from the depletion of fast-turnover C pool. The remaining 35 % increase results from accompanied changes in compartment C age structures. Similarly, the decrease in mean C transit time with rising atmospheric [CO2] results approximately equally from replenishment of C into fast-turnover C pool and subsequent decrease in compartment C age structure. Greatly different from the Rasmussen method, the Olsen method, which does not account for changes in either C age structure or composition of respired C, underestimated impacts of either warming or rising atmospheric [CO2] on C diagnostic time and potentially lead to biases in estimating land C sequestration.

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