M.S. Thesis Research Presentation at The Ohio State University School for Environment and Natural Resources

1. Soil respiration response to canopy disturbance in a Northern Michigan Forest
Conor Flynn
The Ohio State University

2. Outline: Definitions Hypotheses Methods Results & Discussion Conclusion Future directions

3. Soil respiration response to canopy disturbance in a Northern Michigan Forest

4. Soil respiration response to canopy disturbance in a Northern Michigan Forest
Ryan MG, Law BE. Interpreting, measuring, and modeling soil respiration.
Biogeochemistry. 2005.

5. Aspen/maple/oak
Even-aged
Disturbance/mortality
releases understory
Pine/maple/oak
Uneven-aged
Forest age (yrs)
0
10
20
30
40
50
60
70
80
90
100
110
120
Soil respiration response to canopy disturbance in a Northern Michigan Forest:

6. Soil respiration response to canopy disturbance in a Northern Michigan Forest:
The Forest Accelerated Succession ExperimenT (FASET)
Nave LE, Gough CM, Maurer KD, Bohrer G, Hardiman BS, Moine JL, Munoz AB, Nadelhoffer KJ, Sparks JP, Strahm BD, Vogel CS, Curtis PS. Disturbance and the resilience of coupled carbon and nitrogen cycling in a north temperate forest. Journal of Geophysical Research. 2011

7. Soil respiration response to canopy disturbance in a Northern Michigan Forest
Ryan MG, Law BE. Interpreting, measuring, and modeling soil respiration.
Biogeochemistry. 2005.

8. Soil respiration response to canopy disturbance in a Northern Michigan Forest
Ryan MG, Law BE. Interpreting, measuring, and modeling soil respiration.
Biogeochemistry. 2005.

9. Aspen
Oak
FASET
(treatment)
GIRDLED
(released from competition)
Ameriflux
(control)
no change
no change
Experiment Design: 4 Sites

10. Aspen
Oak
FASET
(treatment)
↓ Total Soil Respiration
↓ Rs Sensitivity to Temperature
↑ Total Soil Respiration
↑ Rs Sensitivity to Temperature
Ameriflux
(control)
no change
no change
Hypotheses

11. Aspen
Oak
FASET
(treatment)
↓ Total Soil Respiration
↓ Rs Sensitivity to Temperature
↑ Total Soil Respiration
↑ Rs Sensitivity to Temperature
Ameriflux
(control)
no change
no change
Hypotheses

12. Aspen
Oak
FASET
(treatment)
↓ Total Soil Respiration
↓ Rs Sensitivity to Temperature
↑ Total Soil Respiration
↑ Rs Sensitivity to Temperature
Ameriflux
(control)
no change
no change
Hypotheses

13. Aspen
Oak
FASET
(treatment)
↓ Total Soil Respiration
↓ Rs Sensitivity to Temperature
↑ Total Soil Respiration
↑ Rs Sensitivity to Temperature
Ameriflux
(control)
no change
no change
Hypotheses

14. Methods:
Automated Soil CO2 efflux Measurement

15. Methods:
Automated Soil CO2 efflux Measurement
FASET Aspen Site (FAS)

16. Methods:
Manual Soil CO2 efflux
Measurement

17. Results

18. Results:
Growing Season Soil Respiration - Manual
0
1
2
3
4
5
6
7
8
9
10
153
180
194
208
230
244
Soil CO2 Efflux μmol m-2 s-1
Day of Year
AF EFFLUX
FASET EFFLUX

19. Results:
Growing Season Soil Respiration - Autochambers
0
1
2
3
4
5
6
7
8
9
10
153
180
194
208
230
244
Soil CO2 Efflux μmol m-2 s-1
Day of Year
AF EFFLUX
FASET EFFLUX

20. -3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
129
149
169
189
209
229
Soil CO2 Efflux μmol m-2 s-1
Difference
Day of Year
Difference
FAS-AAS
Results:
Growing Season Soil Respiration - Autochambers

21. -3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
129
149
169
189
209
229
Soil CO2 Efflux μmol m-2 s-1
Difference
Day of Year
Difference
FAS-AAS
FOS-AOS
Results:
Growing Season Soil Respiration - Autochambers

22. Results:
Q10: Soil Respiration Temperature Sensitivity
y = 1.3944e0.0592x R² = 0.465
0
1
2
3
4
5
6
7
8
8
10
12
14
16
18
20
22
Soil CO2 Efflux μmol m-2 s-1
15cm Soil Temperature C
FAS Efflux Q10= 1.81

23. Results:
Q10: Soil Respiration Temperature Sensitivity
y = 1.3944e0.0592x R² = 0.465
0
2
4
6
8
8
10
12
14
16
18
20
22
Soil CO2 Efflux μmol m-2 s-1
15cm Soil Temperature C
FAS Efflux Q10= 1.81
Control
Treatment
AAS
AOS
FAS
FOS
Q10
(r2)
2.93a (0.68)
2.84b
(0.59)
1.81c
(0.47)
2.39d
(0.75)

24. -3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
129
149
169
189
209
229
Soil CO2 Efflux μmol m-2 s-1
Difference
Day of Year
Difference
FAS-AAS
FOS-AOS
Results:
Phenoperiod 1

25. -3.5
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
129
149
169
189
209
229
Soil CO2 Efflux μmol m-2 s-1
Difference
Day of Year
Difference
FAS-AAS
FOS-AOS
Results:
Phenoperiod 2

26. Results:
Soil Respiration Sensitivity:
Phenoperiods
Control
Treatment
AAS
AOS
FAS
FOS
Q10
(r2)
2.93a (0.68)
2.84b
(0.59)
1.81c
(0.47)
2.39d
(0.75)
Phenoperiod 1 Q10
(r2)
2.31a
(0.37)
3.86b
(0.74)
3.12c
(0.68)
2.97c
(0.74)
Phenoperiod 2 Q10
(r2)
2.37a
(0.35)
2.28a
(0.25)
1.27b
(0.04)
1.86a
(0.32)

27. Results:
Soil Respiration Sensitivity:
Phenoperiods
Control
Treatment
AAS
AOS
FAS
FOS
Q10
(r2)
2.93a (0.68)
2.84b
(0.59)
1.81c
(0.47)
2.39d
(0.75)
Phenoperiod 1 Q10
(r2)
2.31a
(0.37)
3.86b
(0.74)
3.12c
(0.68)
2.97c
(0.74)
Phenoperiod 2 Q10
(r2)
2.37a
(0.35)
2.28a
(0.25)
1.27b
(0.04)
1.86a
(0.32)

28. Aspen
Oak
FASET
(treatment)
↓ Total Respiration
(↑ PP1 ; ↓ PP2)
↓ Total Rs Sensitivity to Temperature
(↑PP1; ↓PP2)
↔ Total Respiration
↓ Total Rs Sensitivity to Temperature
(↓PP1; ↓PP2)
Ameriflux
(control)
no change
no change
Conclusions

29. Aspen
Oak
FASET
(treatment)
↓ Total Respiration
(↑ PP1 ; ↓ PP2)
↓ Total Rs Sensitivity to Temperature
(↑PP1; ↓PP2)
↔ Total Respiration
↓ Total Rs Sensitivity to Temperature
(↓PP1; ↓PP2)
Ameriflux
(control)
no change
no change
Conclusions

30. Aspen
Oak
FASET
(treatment)
↓ Total Respiration
(↑ PP1 ; ↓ PP2)
↓ Total Rs Sensitivity to Temperature
(↑PP1; ↓PP2)
↔ Total Respiration
↓ Total Rs Sensitivity to Temperature
(↓PP1; ↓PP2)
Ameriflux
(control)
no change
no change
Conclusions

31. Aspen
Oak
FASET
(treatment)
↓ Total Respiration
(↑ PP1 ; ↓ PP2)
↓ Total Rs Sensitivity to Temperature
(↑PP1; ↓PP2)
↔ Total Respiration
↓ Total Rs Sensitivity to Temperature
(↓PP1; ↓PP2)
Ameriflux
(control)
no change
no change
Conclusions

32. Aspen
Oak
FASET
(treatment)
↓ Total Respiration
(↑ PP1 ; ↓ PP2)
↓ Total Rs Sensitivity to Temperature
(↑PP1; ↓PP2)
↔ Total Respiration
↓ Total Rs Sensitivity to Temperature
(↓PP1; ↓PP2)
Ameriflux
(control)
no change
no change
Conclusions

33. Conclusions
Soil respiration reflects total belowground activity, and responds strongly to aboveground disturbance: less C in, less C out.
Carbon cycle is resistant to natural disturbance as compared to anthropogenic.
In undisturbed forests, root-derived respiration can contribute as much as 50% of total soil respiration.
Heterotrophic respiration can be more sensitive to temperature than autotrophic, but depends on time of year – different drivers.

34. Problems and Solutions:
Future Directions

35. 0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
-3
-2
-1
0
1
2
3
129
149
169
189
209
229
Volumetric Soil Water Content %
FAS Residual Unexplained Soil Respiration
Doy of Year
residuals
SM_15cm2
R² = 0.1422
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
0
0.05
0.1
0.15
0.2
Volumetric Soil Water Content %
Problem:
Soil Respiration Sensitivity to Change in Soil Moisture

36. Problem: Diurnal time-delay (Hysteresis)
3.5
3.7
3.9
4.1
4.3
4.5
4.7
4.9
5.1
5.3
5.5
17.4
17.6
17.8
18
18.2
18.4
18.6
Soil Respiration
Soil Temperature (15cm)
Time
Time
Midnight
Noon
6:00 PM
6:00 AM
6:00 PM
0
1
2
3
4
5
6
7
8
8
13
18
Efflux
15cm Soil Temperature

37. 8
13
18
23
129
149
169
189
209
229
Soil Temperature, C
DOY
15cm Soil Temperature
AAS ST_15cm2
Continuous Wavelet Transform (CWT)
•Can be interpreted as time-localized power spectra (CF Fourier Transform)
•Indicates time, period (i.e. wavelength), and power of signal

38. 8
13
18
23
129
149
169
189
209
229
Soil Temperature, C
DOY
15cm Soil Temperature
AAS ST_15cm2
Continuous Wavelet Transform (CWT)
•Can be interpreted as time-localized power spectra (CF Fourier Transform)
•Indicates time, period (i.e. wavelength), and power of signal

39. Cross-Wavelet Transform (CXT) CXT indicates time-period domains of shared power between two signals CXT also includes phase (lag) information with arrows CXT AAS efflux and ST 15cm:

40. Continuous Wavelet Transform (CWT)
•Can be interpreted as time-localized power spectra (CF Fourier Transform)
•Indicates time, period, and power of signal
0
0.05
0.1
0.15
0.2
129
149
169
189
209
229
Volumetric water content %/%
DOY
15cm Soil Moisture
AAS SM_15cm

41. Cross-Wavelet Transform (CXT) CXT indicates time-period domains of shared power between two signals CXT also includes phase (lag) information with arrows CXT AAS efflux and SM 15cm:

42. Wavelet Analysis: CXT can identify: -Hysteresis time-lags -Variable (episodic, pulsed) controls of soil respiration -CorrelationCausation

43. Acknowledgments
Dr. Peter Curtis
Dr. Gil Bohrer
Dr. Richard Dick
Jen Nietz
Dr. Chris Vogel, UMBS
Dr. Valeriey Ivanov, UM
Lingli He, UM
Alexandra Permar, UNC
…and many other collaborators!

44. Soil respiration is Important
Carbon Neutral?
Questions?

45. Results:
Growing Season Soil Respiration - Autochambers
-1
0
1
2
3
4
129
139
149
159
169
189
199
209
219
230
Soil Respiration Difference
DOY
Soil Respiration Difference AAS-FAS
significant
not significant

47. 0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
-3
-2
-1
0
1
2
3
169
179
189
199
209
219
229
residuals
SM_15cm2
Phenoperiod Residual Analysis
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
-3
-2
-1
0
1
2
3
129
139
149
159
169
y = 2.4628x - 0.2188 R² = 0.0112
-1.5
-1
-0.5
0
0.5
1
1.5
2
0
0.05
0.1
0.15
0.2
y = 0.5907ln(x) + 2.0034 R² = 0.1899
-3
-2
-1
0
1
2
3
4
0
0.05
0.1
0.15

48. Growing Season Soil Respiration
Driver: Soil Temperature
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
129
149
169
189
209
229
Soil Water Potential, Kpa
SWC %
SM_15cm2
convert 15cm SM to
Matric

49. Growing Season Soil Respiration
Driver: Soil Temperature
0
5
10
15
20
25
0
1
2
3
4
5
6
7
8
129
149
169
189
209
229
Soil CO2 Efflux μmol m-2 s-1
Day of Year
FAS efflux
ST_15cm2

50. Phenoperiods:
Growing Season

51. -2
0
2
4
6
8
10
12
14
129
149
169
189
209
229
AF C Fluxes
Average of REgf
NEE
GPP
AAS efflux
AOS efflux

52. Substituting Rs for modeled Re in GPP calculations
-4
-2
0
2
4
6
8
10
12
14
16
129
149
169
189
209
229
NEEgf
REgf
GPP (NEE+Regf)
GPP (NEE+Rs)

53. Soil respiration response to canopy disturbance in a Northern Michigan Forest

54. Heterotrophic Soil Respiration:
Biodiversity

55. Modified from Smith P, Fang C. Carbon cycle: A warm response by soils. Nature. 2010 March 24
What is the soil respiration response to succession?