1. Impacts of Nitrogen Deposition on Microbial
Community Carbon Dynamics in Forest Soils
Daniel H. Buckley
School of Integrative Plant Science
Christine Goodale
Ecology and Evolutionary Biology

2. Friedlingstein et al (2006) Journal of Climate. 19:3337
The terrestrial C-cycle is difficult to predict

3. Lin Zhang et al., 2012, Atmos. Chem. Phys., 12, 4539-4554

4. NADP National Trends Network (NTN)

5. Rousk et al. 2010
Soil pH is a Driver of Microbial Diversity

6. Control
(NH4)2SO4
50 kg N
57 kg S
NaNO3
50 kg N
Background Deposition
- 6.6 kg N ha-1 yr-1
- 6.8 kg S ha-1 yr-1
Long Term N x S
Enrichment Experiment
Sulfur
57 kg S
Started 2011, 3 sites x 2 stand ages
40 x 40 m plots + 10 m buffer
Amendments (ha-1 yr-1)

7. Tree Growth Response
Pre-Treatment (2009-2010) Post-Treatment (2011-2014)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Control NaNO3 (NH4)2SO4 Sulfur
Pre-TreatmentOn-growth
2009-2010(tha-1yr-1)
Other
WP
WA
SM
RO
RM
QA
EH
BC
BB
AB
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Control NaNO3 (NH4)2SO4 Sulfur
Post-TreatmentOn-growth
2014-2011(tha-1yr-1)
Other
WP
WA
SM
RO
RM
QA
EH
BC
BB
AB
Species

8. Soil pH at 5 years
3.5
4.0
4.5
5.0
5.5
Control NaNO3 (NH4)2SO4 Sulfur
0-10 cm Mineral
Treatment: p < 0.0001; NO3 > Control > AS, S
Stand: p < 0.0001; CC2, MP2 > CC1, MP1, BH2 > BH1
Treatment x Stand: p < 0.0001

9. 0.2
0.3
0.4
0.5
0.6
0.7
Year 1 Year 2 Year 3 Year 4
LitterDecomp.Rate(kyr-1)
Control
NaNO3
(NH4)2SO4
Sulfur
Litter Decomposition Rate
p = 0.01
p = 0.05
p = 0.001
Year of litter decomposition (t)
p = 0.02
a
b
ab
ab
ab
b
a
ab
ab
b
a
ab

10. Site***
Treatment***
Site x Treatment***
Stand Age***
Site x Stand Age***
Bacterial Community Composition

11. Bacterial Community Composition
Site x Stand Age***
4.7 4.8 4.9 4.7 4.8 4.9
4.6
4.7
4.8
4.6 4.7 4.7
4.5
4.6
4.7
4.6
4.5
4.6
4.3
4.4
4.5
4.5
4.3
4.6
3.9
3.9
4.2
4.4
4.1
4.6
4.4
4.6
4.2
0
20
40
60
80
100
120
BH BH CC CC MP MP
1 2 1 2 1 2
CStocks(t/ha)
40-50 30-40 20-30 10-20 0-10 FF
Bald Hill Carter Creek Mt. Pleasant

12. PrimaryForestSecondaryForest Bald Hill Carter Creek Mount Pleasant

13. Fungal Community Composition

14. 2,724 Total Core OTUs
N + S
372 OTU
S only
169 OTU
N only
164 OTU 62 OTU
~470 Total Responsive OTUs
160-222 (NH4)2SO4 specific
118 N response
94 S/pH response
13-75 NaNO3 specific
0-46 S0 specific
Responsive Bacterial Taxa

16. 13C-Cellulose
Verrucomicrobia
Chloroflexi
Proteobacteria
Bacteroidetes
Planctomycetes
Melainabacteria
Log2FoldChange

17. Impacts of Nitrogen Deposition on Microbial
Community Carbon Dynamics in Forest Soils
School of Integrative Plant Science
Daniel H Buckley
Spencer Debenport
Ecology and Evolutionary Biology
Christine Goodale
Bhavya Sridhar
Charlotte Levy
Guin Fredriksen

19. Foliar Litterfall
Treatments
start
Treatments
start
Treatments
start

20. No pre-treatment differences in soil
properties by later treatment.*
0
20
40
60
80
100
120
Ctrl NO3 AS S
SoilCStock(t/ha)
40-50 30-40 20-30
10-20 0-10 FF
0.0
0.5
1.0
1.5
2.0
Ctrl NO3 AS S
SoilSStock(t/ha)
40-50 30-40 20-30
10-20 0-10 FF
-5
5
15
25
35
45
3.8 4.0 4.2 4.4 4.6 4.8 5.0
pH
Control
NaNO3
(NH4)2SO4
Sulfur
-5
5
15
25
35
45
5 10 15 20 25
C/N Ratio
Control
NaNO3
(NH4)2SO4
Sulfur
*MP1 Control had higher pH
than treatment plots. Other
stands were better-matched.

21. 4.7 4.8 4.9 4.7 4.8 4.9
4.6
4.7
4.8
4.6 4.7 4.7
4.5
4.6
4.7
4.6
4.5
4.6
4.3
4.4
4.5
4.5
4.3
4.6
3.9
3.9
4.2
4.4
4.1
4.6
4.4
4.6
4.2
0
20
40
60
80
100
120
BH BH CC CC MP MP
1 2 1 2 1 2
CStocks(t/ha)
40-50 30-40 20-30 10-20 0-10 FF
Pre-treatment: C stocks varied by site and
stand age, and surface pH varied by site.
Four plots per stand,
Four cores/plot.
Bars labeled with
stand mean pH
Bald Hill Carter Creek Mt. Pleasant
Primary or secondary
 (post-ag.) forest

22. 0
50
100
150
200
Control NaNO3 (NH4)2SO4 Sulfur
CO2Flux(mgC/m2/hr) P = 0.003P = 0.14P = 0.28
-80
-60
-40
-20
0
Control NaNO3 (NH4)2SO4 Sulfur
AverageCH4Flux(ug
C/m2/hr)
P = 0.05
P = 1.0P = 0.64
0
2
4
6
8
10
12
Control NaNO3 (NH4)2SO4 Sulfur
MedianN2OFlux
(ugN/m2/hr)
Gas Flux at 5 years

23. 20%
40%
60%
80%
100%
0 1 2 3 4
LitterCRemaining(%)
Control
NaNO3
(NH4)2SO4
Sulfur
Year of litter decomp.
1 2 3 4 Year of N x S treatment
Litter Carbon Loss
5
P = 0.028
S > AS
(NSD from ctrl)
P = 0.0008
S, AS > Ctrl
(+NO3 NSD)
P = 0.04
S > Ctrl
(+N NSD)