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Contrasting diel hysteresis between soil autotrophic and heterotrophic respiration in a desert ecosystem under different rainfall scenarios.

Song W, Chen S, Zhou Y, Wu B, Zhu Y, Lu Q, Lin G - Sci Rep (2015)

Bottom Line: Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season.We found contrasting responses in the diel hysteresis of R(A) and R(H) to soil temperature, with a clockwise hysteresis loop for R(H) but a counter-clockwise hysteresis loop for R(A).Rain addition significantly increased the magnitude of diel hysteresis for both R(H) and R(A) on Day 6, but had no influence on either on Day 16 when soil moisture was much lower.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084, China.

ABSTRACT
Diel hysteresis occurs often between soil CO2 efflux (R(S)) and temperature, yet, little is known if diel hysteresis occurs in the two components of R(S), i.e., autotrophic respiration (R(A)) and heterotrophic respiration (R(H)), and how diel hysteresis will respond to future rainfall change. We conducted a field experiment in a desert ecosystem in northern China simulating five different scenarios of future rain regimes. Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season. We found contrasting responses in the diel hysteresis of R(A) and R(H) to soil temperature, with a clockwise hysteresis loop for R(H) but a counter-clockwise hysteresis loop for R(A). Rain addition significantly increased the magnitude of diel hysteresis for both R(H) and R(A) on Day 6, but had no influence on either on Day 16 when soil moisture was much lower. These findings underline the different roles of biological (i.e. plant and microbial activities) and physical-chemical (e.g. heat transport and inorganic CO2 exchange) processes in regulating the diel hysteresis of R(A) and R(H), which should be considered when estimating soil CO2 efflux in desert regions under future rainfall regime.

No MeSH data available.


Related in: MedlinePlus

(a) Daily precipitation during the experimental period from 1 May to 1 October. (b,c): Soil water content (SWC) at 10 cm depth in vegetated soil and bare soil of a N tangutorum dominated desert ecosystem. (d) Daily mean air temperature (Ta) during the experimental period. (e,f): Soil temperature at 10 cm depth (Ts) in vegetated and bare soils. Long solid arrows represent the timing of rain addition treatments; short solid and dashed arrows represent the measurement time on Day 6 and Day 16 after the rain addition treatments, respectively.
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f1: (a) Daily precipitation during the experimental period from 1 May to 1 October. (b,c): Soil water content (SWC) at 10 cm depth in vegetated soil and bare soil of a N tangutorum dominated desert ecosystem. (d) Daily mean air temperature (Ta) during the experimental period. (e,f): Soil temperature at 10 cm depth (Ts) in vegetated and bare soils. Long solid arrows represent the timing of rain addition treatments; short solid and dashed arrows represent the measurement time on Day 6 and Day 16 after the rain addition treatments, respectively.

Mentions: We measured the surface (0–10 cm) soil water content (SWC) on Days 6 and 16 following the rain addition treatments each month. As expected, SWC was strongly affected by rain addition treatments in both vegetated and bare soils (Fig. 1). The magnitude of change in SWC depended on the amount of rain added and the measurement day. Day 6 usually showed a higher increase in SWC than Day 16 during the growing season except for August due to a heavy natural rainfall event on 25thAugust (25.8 mm). There was no significant difference in SWC between the vegetated and bare soils under a given rain addition treatment on each measurement day32.


Contrasting diel hysteresis between soil autotrophic and heterotrophic respiration in a desert ecosystem under different rainfall scenarios.

Song W, Chen S, Zhou Y, Wu B, Zhu Y, Lu Q, Lin G - Sci Rep (2015)

(a) Daily precipitation during the experimental period from 1 May to 1 October. (b,c): Soil water content (SWC) at 10 cm depth in vegetated soil and bare soil of a N tangutorum dominated desert ecosystem. (d) Daily mean air temperature (Ta) during the experimental period. (e,f): Soil temperature at 10 cm depth (Ts) in vegetated and bare soils. Long solid arrows represent the timing of rain addition treatments; short solid and dashed arrows represent the measurement time on Day 6 and Day 16 after the rain addition treatments, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663751&req=5

f1: (a) Daily precipitation during the experimental period from 1 May to 1 October. (b,c): Soil water content (SWC) at 10 cm depth in vegetated soil and bare soil of a N tangutorum dominated desert ecosystem. (d) Daily mean air temperature (Ta) during the experimental period. (e,f): Soil temperature at 10 cm depth (Ts) in vegetated and bare soils. Long solid arrows represent the timing of rain addition treatments; short solid and dashed arrows represent the measurement time on Day 6 and Day 16 after the rain addition treatments, respectively.
Mentions: We measured the surface (0–10 cm) soil water content (SWC) on Days 6 and 16 following the rain addition treatments each month. As expected, SWC was strongly affected by rain addition treatments in both vegetated and bare soils (Fig. 1). The magnitude of change in SWC depended on the amount of rain added and the measurement day. Day 6 usually showed a higher increase in SWC than Day 16 during the growing season except for August due to a heavy natural rainfall event on 25thAugust (25.8 mm). There was no significant difference in SWC between the vegetated and bare soils under a given rain addition treatment on each measurement day32.

Bottom Line: Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season.We found contrasting responses in the diel hysteresis of R(A) and R(H) to soil temperature, with a clockwise hysteresis loop for R(H) but a counter-clockwise hysteresis loop for R(A).Rain addition significantly increased the magnitude of diel hysteresis for both R(H) and R(A) on Day 6, but had no influence on either on Day 16 when soil moisture was much lower.

View Article: PubMed Central - PubMed

Affiliation: Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing 100084, China.

ABSTRACT
Diel hysteresis occurs often between soil CO2 efflux (R(S)) and temperature, yet, little is known if diel hysteresis occurs in the two components of R(S), i.e., autotrophic respiration (R(A)) and heterotrophic respiration (R(H)), and how diel hysteresis will respond to future rainfall change. We conducted a field experiment in a desert ecosystem in northern China simulating five different scenarios of future rain regimes. Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season. We found contrasting responses in the diel hysteresis of R(A) and R(H) to soil temperature, with a clockwise hysteresis loop for R(H) but a counter-clockwise hysteresis loop for R(A). Rain addition significantly increased the magnitude of diel hysteresis for both R(H) and R(A) on Day 6, but had no influence on either on Day 16 when soil moisture was much lower. These findings underline the different roles of biological (i.e. plant and microbial activities) and physical-chemical (e.g. heat transport and inorganic CO2 exchange) processes in regulating the diel hysteresis of R(A) and R(H), which should be considered when estimating soil CO2 efflux in desert regions under future rainfall regime.

No MeSH data available.


Related in: MedlinePlus