Limits...
Temperature response of soil respiration in a Chinese pine plantation: hysteresis and seasonal vs. diel Q10.

Jia X, Zha T, Wu B, Zhang Y, Chen W, Wang X, Yu H, He G - PLoS ONE (2013)

Bottom Line: Progress on these issues will contribute to reduced uncertainties in carbon cycle modeling.The hysteresis may be associated with the confounding effects of microbial population dynamics and/or litter input.In addition, daily Q10 decreased with increasing Ts , which may contribute feedback to the climate system under global warming scenarios.

View Article: PubMed Central - PubMed

Affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing, China.

ABSTRACT
Although the temperature response of soil respiration (Rs ) has been studied extensively, several issues remain unresolved, including hysteresis in the Rs -temperature relationship and differences in the long- vs. short-term Rs sensitivity to temperature. Progress on these issues will contribute to reduced uncertainties in carbon cycle modeling. We monitored soil CO2 efflux with an automated chamber system in a Pinus tabulaeformis plantation near Beijing throughout 2011. Soil temperature at 10-cm depth (Ts ) exerted a strong control over Rs , with the annual temperature sensitivity (Q10) and basal rate at 10°C (Rs10) being 2.76 and 1.40 µmol m(-2) s(-1), respectively. Both Rs and short-term (i.e., daily) estimates of Rs10 showed pronounced seasonal hysteresis with respect to Ts , with the efflux in the second half of the year being larger than that early in the season for a given temperature. The hysteresis may be associated with the confounding effects of microbial population dynamics and/or litter input. As a result, all of the applied regression models failed to yield unbiased estimates of Rs over the entire annual cycle. Lags between Rs and Ts were observed at the diel scale in the early and late growing season, but not in summer. The seasonality in these lags may be due to the use of a single Ts measurement depth, which failed to represent seasonal changes in the depth of CO2 production. Daily estimates of Q10 averaged 2.04, smaller than the value obtained from the seasonal relationship. In addition, daily Q10 decreased with increasing Ts , which may contribute feedback to the climate system under global warming scenarios. The use of a fixed, universal Q10 is considered adequate when modeling annual carbon budgets across large spatial extents. In contrast, a seasonally-varying, environmentally-controlled Q10 should be used when short-term accuracy is required.

Show MeSH

Related in: MedlinePlus

Diel soil respiration (Rs) and temperature (Ts) (A–C), diel Rs vs. Ts (D–I), their lag correlations (G–I).Mean values for March, June and October are shown. Grey circles in (A–C): Rs; Black circles in (A–C): Ts. Ts was monitored at 10-cm depth. The dashed lines in (G–I) are reference lines for the zero lag.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3585128&req=5

pone-0057858-g006: Diel soil respiration (Rs) and temperature (Ts) (A–C), diel Rs vs. Ts (D–I), their lag correlations (G–I).Mean values for March, June and October are shown. Grey circles in (A–C): Rs; Black circles in (A–C): Ts. Ts was monitored at 10-cm depth. The dashed lines in (G–I) are reference lines for the zero lag.

Mentions: The lag between diel oscillations in Rs and Ts showed a strong seasonal pattern, with almost no lag in summer but lags up to five hours in the early and late growing season (Fig. 4C). In March and October, Ts reached its daily minimum at 08:00 and peaked at around 15:00 (Fig. 6A, C). In March Rs was out-of-phase with Ts, reaching its daily maximum at 11:00–14:00 and daily minimum at 19:00. In October, Rs was also out-of-phase with Ts, peaking at around 12:00 and reaching a minimum at around 24:00. The lags in March and October led to hysteresis loops (Fig. 6D, F), and the correlation between Rs and Ts was strongest after lagging Rs by three hours (Fig. 6G, I). In contrast, Rs was in phase with Ts in June (Fig. 6B, E), with the zero lag generating the highest correlation coefficient (Fig. 6H).


Temperature response of soil respiration in a Chinese pine plantation: hysteresis and seasonal vs. diel Q10.

Jia X, Zha T, Wu B, Zhang Y, Chen W, Wang X, Yu H, He G - PLoS ONE (2013)

Diel soil respiration (Rs) and temperature (Ts) (A–C), diel Rs vs. Ts (D–I), their lag correlations (G–I).Mean values for March, June and October are shown. Grey circles in (A–C): Rs; Black circles in (A–C): Ts. Ts was monitored at 10-cm depth. The dashed lines in (G–I) are reference lines for the zero lag.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585128&req=5

pone-0057858-g006: Diel soil respiration (Rs) and temperature (Ts) (A–C), diel Rs vs. Ts (D–I), their lag correlations (G–I).Mean values for March, June and October are shown. Grey circles in (A–C): Rs; Black circles in (A–C): Ts. Ts was monitored at 10-cm depth. The dashed lines in (G–I) are reference lines for the zero lag.
Mentions: The lag between diel oscillations in Rs and Ts showed a strong seasonal pattern, with almost no lag in summer but lags up to five hours in the early and late growing season (Fig. 4C). In March and October, Ts reached its daily minimum at 08:00 and peaked at around 15:00 (Fig. 6A, C). In March Rs was out-of-phase with Ts, reaching its daily maximum at 11:00–14:00 and daily minimum at 19:00. In October, Rs was also out-of-phase with Ts, peaking at around 12:00 and reaching a minimum at around 24:00. The lags in March and October led to hysteresis loops (Fig. 6D, F), and the correlation between Rs and Ts was strongest after lagging Rs by three hours (Fig. 6G, I). In contrast, Rs was in phase with Ts in June (Fig. 6B, E), with the zero lag generating the highest correlation coefficient (Fig. 6H).

Bottom Line: Progress on these issues will contribute to reduced uncertainties in carbon cycle modeling.The hysteresis may be associated with the confounding effects of microbial population dynamics and/or litter input.In addition, daily Q10 decreased with increasing Ts , which may contribute feedback to the climate system under global warming scenarios.

View Article: PubMed Central - PubMed

Affiliation: School of Soil and Water Conservation, Beijing Forestry University, Beijing, China.

ABSTRACT
Although the temperature response of soil respiration (Rs ) has been studied extensively, several issues remain unresolved, including hysteresis in the Rs -temperature relationship and differences in the long- vs. short-term Rs sensitivity to temperature. Progress on these issues will contribute to reduced uncertainties in carbon cycle modeling. We monitored soil CO2 efflux with an automated chamber system in a Pinus tabulaeformis plantation near Beijing throughout 2011. Soil temperature at 10-cm depth (Ts ) exerted a strong control over Rs , with the annual temperature sensitivity (Q10) and basal rate at 10°C (Rs10) being 2.76 and 1.40 µmol m(-2) s(-1), respectively. Both Rs and short-term (i.e., daily) estimates of Rs10 showed pronounced seasonal hysteresis with respect to Ts , with the efflux in the second half of the year being larger than that early in the season for a given temperature. The hysteresis may be associated with the confounding effects of microbial population dynamics and/or litter input. As a result, all of the applied regression models failed to yield unbiased estimates of Rs over the entire annual cycle. Lags between Rs and Ts were observed at the diel scale in the early and late growing season, but not in summer. The seasonality in these lags may be due to the use of a single Ts measurement depth, which failed to represent seasonal changes in the depth of CO2 production. Daily estimates of Q10 averaged 2.04, smaller than the value obtained from the seasonal relationship. In addition, daily Q10 decreased with increasing Ts , which may contribute feedback to the climate system under global warming scenarios. The use of a fixed, universal Q10 is considered adequate when modeling annual carbon budgets across large spatial extents. In contrast, a seasonally-varying, environmentally-controlled Q10 should be used when short-term accuracy is required.

Show MeSH
Related in: MedlinePlus