impacts of nitrogen deposition on microbial community carbon dynamics in forest soils
TRANSCRIPT
Impacts of Nitrogen Deposition on Microbial Community Carbon Dynamics in Forest Soils
Daniel H. BuckleySchool of Integrative Plant Science
Christine GoodaleEcology and Evolutionary Biology
Friedlingstein et al (2006) Journal of Climate. 19:3337
The terrestrial C-cycle is difficult to predict
Lin Zhang et al., 2012, Atmos. Chem. Phys., 12, 4539-4554
NADP National Trends Network (NTN)
Rousk et al. 2010
Soil pH is a Driver of Microbial Diversity
Control
(NH4)2SO4
50 kg N57 kg S
NaNO350 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
Sulfur57 kg S
Started 2011, 3 sites x 2 stand ages40 x 40 m plots + 10 m bufferAmendments (ha-1 yr-1)
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-
Trea
tmen
t On-
grow
th20
09-2
010
(t h
a-1yr
-1)
Other
WP
WA
SM
RO
RM
QA
EH
BC
BB
AB0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
Control NaNO3 (NH4)2SO4 Sulfur
Post
-Tre
atm
ent O
n-gr
owth
2014
-201
1 (t
ha-1
yr-1
)
Other
WP
WA
SM
RO
RM
QA
EH
BC
BB
AB
Species
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
0.2
0.3
0.4
0.5
0.6
0.7
Year 1 Year 2 Year 3 Year 4
Litt
er D
ecom
p. R
ate
(k y
r-1) Control
NaNO3(NH4)2SO4Sulfur
Litter Decomposition Rate
p = 0.01
p = 0.05
p = 0.001
Year of litter decomposition (t)
p = 0.02
a
b
abab
ab
b
aab
ab
b
aab
Site*** Treatment*** Site x Treatment*** Stand Age*** Site x Stand Age***
Bacterial Community Composition
Bacterial Community Composition
Site x Stand Age***
4.7 4.8 4.9 4.7 4.8 4.9
4.6 4.74.8 4.6 4.7 4.7
4.54.6
4.74.6 4.5
4.6
4.3
4.4
4.5
4.54.3
4.6
3.9
3.9
4.2
4.4
4.14.6
4.44.6
4.2
0
20
40
60
80
100
120
BH BH CC CC MP MP
1 2 1 2 1 2
C St
ocks
(t/h
a)
40-50 30-40 20-30 10-20 0-10 FF
Bald Hill Carter Creek Mt. Pleasant
Prim
ary
Fore
stSe
cond
ary
Fore
stBald Hill Carter Creek Mount Pleasant
Fungal Community Composition
2,724 Total Core OTUs
N + S372 OTU
S only169 OTU
N only164 OTU
94 OTU
118 O
TU
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
13C-Cellulose
VerrucomicrobiaChloroflexi
Proteobacteria
BacteroidetesPlanctomycetes
Melainabacteria
Log
2 Fol
d C
hang
e
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
Foliar Litterfall
Treatments start
Treatments start
Treatments start
No pre-treatment differences in soil properties by later treatment.*
0
20
40
60
80
100
120
Ctrl NO3 AS S
Soil
C St
ock
(t/h
a)
40-50 30-40 20-3010-20 0-10 FF
0.0
0.5
1.0
1.5
2.0
Ctrl NO3 AS S
Soil
S St
ock
(t/h
a)
40-50 30-40 20-3010-20 0-10 FF
-5
5
15
25
35
45
3.8 4.0 4.2 4.4 4.6 4.8 5.0pH
ControlNaNO3(NH4)2SO4Sulfur
-5
5
15
25
35
45
5 10 15 20 25C/N Ratio
ControlNaNO3(NH4)2SO4Sulfur
*MP1 Control had higher pH than treatment plots. Other stands were better-matched.
4.7 4.8 4.9 4.7 4.8 4.9
4.6 4.74.8 4.6 4.7 4.7
4.54.6
4.74.6 4.5
4.6
4.3
4.4
4.5
4.54.3
4.6
3.9
3.9
4.2
4.4
4.14.6
4.44.6
4.2
0
20
40
60
80
100
120
BH BH CC CC MP MP
1 2 1 2 1 2
C St
ocks
(t/h
a)
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
0
50
100
150
200
Control NaNO3 (NH4)2SO4 Sulfur
CO2
Flux
(mg
C/m
2/hr
)P = 0.003P = 0.14P = 0.28
-80
-60
-40
-20
0
Control NaNO3 (NH4)2SO4 Sulfur
Aver
age
CH4
Flux
(ug
C/m
2/hr
)
P = 0.05P = 1.0P = 0.64
0
2
4
6
8
10
12
Control NaNO3 (NH4)2SO4 Sulfur
Med
ian
N2O
Flu
x (u
g N
/m2/
hr)
Gas Flux at 5 years
20%
40%
60%
80%
100%
0 1 2 3 4
Litt
er C
Rem
aini
ng (%
)
ControlNaNO3(NH4)2SO4Sulfur
Year of litter decomp. 1 2 3 4 Year of N x S treatment
Litter Carbon Loss
5
P = 0.028S > AS
(NSD from ctrl)
P = 0.0008S, AS > Ctrl
(+NO3 NSD)P = 0.04S > Ctrl
(+N NSD)