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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

Relationships between diel soil CO2 efflux and soil temperature at 10 cm soil depth on Days 6 and 16 after the rain addition treatments during the growing season.(a,d) Soil CO2 efflux in the vegetated soils (total soil CO2 efflux, RS), (b,e) soil CO2 efflux in the bare soils (heterotrophic respiration, RH), (c,f) calculated autotrophic respiration (RA). Dotted arrows indicate the directions of the hysteresis loop.
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f2: Relationships between diel soil CO2 efflux and soil temperature at 10 cm soil depth on Days 6 and 16 after the rain addition treatments during the growing season.(a,d) Soil CO2 efflux in the vegetated soils (total soil CO2 efflux, RS), (b,e) soil CO2 efflux in the bare soils (heterotrophic respiration, RH), (c,f) calculated autotrophic respiration (RA). Dotted arrows indicate the directions of the hysteresis loop.

Mentions: Plots of the diel dynamics of RS, RH and RA against soil temperature on Day 6 and Day 16 following the rain addition treatments are shown in Fig. 2. A clockwise diel pattern of hysteresis with respect to soil temperature was found for RS and RH on both measurement days, with higher rate of RS and RH when soil temperature was increasing during daytime, and lower rate when temperature was decreasing during nighttime (Fig. 2a,b,d,e). The rate of RS and RH reached the maximum value between 12:00–15:00 and then gradually decreased to minimum value between 3:00–6:00. However, the maximum rate of RA occurred between 18:00–21:00, and the minimum occurred between 6:00–9:00 despite the increase in soil temperature (Fig. 2c,f). Diel rate of RA exhibited a counter-clockwise effect with soil temperature, that is, for a given temperature, the rate of RA at nighttime was higher than at daytime.


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)

Relationships between diel soil CO2 efflux and soil temperature at 10 cm soil depth on Days 6 and 16 after the rain addition treatments during the growing season.(a,d) Soil CO2 efflux in the vegetated soils (total soil CO2 efflux, RS), (b,e) soil CO2 efflux in the bare soils (heterotrophic respiration, RH), (c,f) calculated autotrophic respiration (RA). Dotted arrows indicate the directions of the hysteresis loop.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Relationships between diel soil CO2 efflux and soil temperature at 10 cm soil depth on Days 6 and 16 after the rain addition treatments during the growing season.(a,d) Soil CO2 efflux in the vegetated soils (total soil CO2 efflux, RS), (b,e) soil CO2 efflux in the bare soils (heterotrophic respiration, RH), (c,f) calculated autotrophic respiration (RA). Dotted arrows indicate the directions of the hysteresis loop.
Mentions: Plots of the diel dynamics of RS, RH and RA against soil temperature on Day 6 and Day 16 following the rain addition treatments are shown in Fig. 2. A clockwise diel pattern of hysteresis with respect to soil temperature was found for RS and RH on both measurement days, with higher rate of RS and RH when soil temperature was increasing during daytime, and lower rate when temperature was decreasing during nighttime (Fig. 2a,b,d,e). The rate of RS and RH reached the maximum value between 12:00–15:00 and then gradually decreased to minimum value between 3:00–6:00. However, the maximum rate of RA occurred between 18:00–21:00, and the minimum occurred between 6:00–9:00 despite the increase in soil temperature (Fig. 2c,f). Diel rate of RA exhibited a counter-clockwise effect with soil temperature, that is, for a given temperature, the rate of RA at nighttime was higher than at daytime.

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