Regenerace lesních ekosystémů z
antropogenní acidifikace
- dlouhodobý monitoring, experimenty a
biogeochemické modelování
Filip Oulehle, Jakub Hruška, Pavel Krám, Tomáš Chuman, Oldřich Myška,
Tomáš Kolář, Jiří Kopáček, Jack Cosby, Dick Wright, Chris Evans
Filip.Oulehle@geology.cz
Six things that I am going to talk about:
• Global extent of acid deposition (S and N)
• Chemical recovery of surface waters
• Effects of acid deposition on forest soil carbon
accumulation
• Effects of acid deposition on DOC leaching from
soils
• Effects of acid deposition on forest productivity
• Coupled C and N dynamics in MAGIC model
Global extent of sulphur and nitrogen deposition
Simulation of future (2030) S deposition using CLE
(Current Legislation scenario)
Total S deposition (mg m-2 yr-1)
2000
Total N deposition (mg m-2 yr-1)
Smith S.J. et al., 2011, ATMOSPHERIC CHEMISTRY AND PHYSICS, 11, 1101–1116
Ratio of total N deposition for scenario CLE (2030)
compared to base simulation (2000)
2000
Dentener F. et al., 2006, GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 20, GB4003
Acidifikace půd
H2SO4 + BC = (BC)SO4 + 2H+
Al(OH)3 + 3H+ = Al3+ + 3H2O
KH
Ca
H
H
Mg
H
Mg
H
Mg
H
Mg
H
H
Ca
H
K
Al
MgAl
Ca
H
Ca
Na
Na
Na
MgAl
H
K
Al
Ca
Ca
Al
Ca
K
K
K
Mg
(1)
(2)
Ca
H
Na
H
H
Mg
H
Chemical recovery of surface waters
• Glacial lakes in the Sumava Mts.
– Monitoring since 1984
Oulehle F., Chuman T., Majer V., Hruška J. (2013). Biogeochemistry 116 (1-3): 83-101.
Chemical recovery of surface waters
Hruška J. et al. (2009). Živa 4: 189-192. Oulehle F., et al. (2013). Biogeochemistry 116 (1-3): 83-101.
Z Score
4
3
2
1
0
-1
-2
-3
SO4
4
3
2
1
0
-1
-2
1984
1990
1995
2000
3
2005
2010
Al
-3
1984
1990
3
2
1995
2000
2005
2010
2000
2005
2010
DOC
2
1
1
0
-1
0
-2
-1
-3
4
pH
1984
1990
1995
2000
2005
2010
NO3
3
2
1
0
-1
-2
1984
1990
1995
2000
2005
2010
-2
1984
1990
1995
Soil Carbon Cycle
Plants
3
CO2
litter C
1
Soil Organic
Matter
(SOM)
respiration
Decomposer
Turnover
4
2
Dissolved
Organic
Material
(DOM)
DOC DON
Effects of acid deposition on soil C accumulation
Experimental evidence:
- Suppression of litter decomposition under simulated acid (S) deposition (e.g. Pennanen et
al., 1998; Persson et al., 1989)
- Adverse effect of aluminium on C availability for microorganisms (e.g. Scheel et al., 2007)
- pH effect on microbial enzyme activity (e.g. Sinsabaugh, 2010)
Al addition (as AlCl3):
Al addition:
effects on soil water
chemistry
effects on soil
respiration
C
A2
Mulder J. et al., 2001, WATER, AIR AND SOIL POLLUTION 130: 989-994
Effects of acid deposition on soil C accumulation
S and N deposition (kg ha-1 yr-1)
Long-term evidence:
- Across Czech forest catchments (n=14), S bulk deposition explained 32% variability in
soil C/N ratio and 50% variability in forest floor depth (Oulehle et al., 2008)
Nacetin spruce forest research plot:
Wet deposition of sulphur (top) and nitrogen (bottom) in
Europe based on the EMEP model
60
S throughfall
N bulk
50
40
30
20
10
0
Source www.emep.int
Forest floor OM pool (kg m-2)
1994
1999
20
2004
2009
Forest floor mass
Forest floor C pool
15
10
5
5.80
5.33
4.18
3.74
1994
1997
2003
2010
0
Oulehle F, Evans C.D., Hofmeister J et al., 2011, GLOBAL CHANGE BIOLOGY 17, 3115-3129
S and N deposition (kg ha-1 yr-1)
Effects of acid deposition on soil C accumulation
Nacetin spruce forest research plot:
-Forest floor C pool reduced by 47% since 1994
60
S throughfall
N bulk
50
40
y = -2.60x + 48.85
R² = 0.89
30
20
10
0
1994
1999
2004
2009
dC/dS = 509
Forest floor OM pool (kg m-2)
-Total S deposition reduced by 77% since 1994
Forest floor mass
Forest floor C pool
20
y=-0.133x + 269.83
R2=0.95
15
10
5
5.80
5.33
4.18
3.74
1994
1997
2003
2010
0
Oulehle F, Evans C.D., Hofmeister J et al., 2011, GLOBAL CHANGE BIOLOGY 17, 3115-3129
Conclusions
• It appears that past acidification caused the suppression of decomposition leading to the
accumulation of a large pool of organic matter on the forest floor. The alleviation of this
acidification pressure over the last two decades appears to have triggered the remobilisation
of the soil C pool.
Soil Carbon Cycle
Plants
3
CO2
litter C
1
Soil Organic
Matter
(SOM)
respiration
Decomposer
Turnover
4
2
Dissolved
Organic
Material
(DOM)
DOC DON
Effects of acid deposition on DOC
Why is dissolved organic carbon (DOC)
important ?
• Important feature of many aquatic ecosystems with
wide-ranging ecological impacts
– Effects on aquatic metabolism as a substrate for
heterotrophic production
– Influence on primary production through light
availability
– Resposible for transport of many organic pollutants
and heavy metals
– Effects on water chemistry, e.g. pH
Vinnetou and Plitvice Lakes
National Park in Croatia
Why is dissolved organic carbon (DOC) important ?
DOC has increased:
4.0
In much of Europe and North America
•
In lakes and streams
•
In forests and moorlands
•
In waterlogged and aerated soils
•
At high and low flows
DOC (standardised
concentrations)
•
3.0
Acid Water Monitoring Network (UK)
2.0
1.0
0.0
-1.0
-2.0
1988
1993
1998
2003
2008
COD (standardised
concentrations)
3.0
2.0
Drinking Water Reservoirs (CZ)
1.0
0.0
-1.0
-2.0
Prague 2002
-3.0
1988
1993
1998
2003
2008
Effects of acid deposition on DOC
Strong evidence of a relationship between acid deposition and organic matter solubility
Solubility of DOC is dependent on:
• Acidity
• Ionic strength
• Aluminium concentration
Results from acidity manipulation
experiment in UK
Acid treatment – H2SO4
Alkaline treatment - NaOH + MgCl2
2.2
Decomposition of organic matter (which
produces DOC) also affected by pH, …and N
Temporal coherence between SO4 declines and
DOC increases in Central European catchments
Treatment/control standardised DOC
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2
Treatment/control standardised H
Oulehle F. and Hruska J., 2009, ENVIRONMENTAL POLLUTION 157: 3433-3439
Consistent, positive DOC response to pH
change at all sites, which can be described
by a simple, general relationship, such that a
1 unit increase in soil solution pH is sufficient
to more than double DOC concentrations.
Evans C.D. ,2012, GLOBAL CHANGE BIOLOGY 18: 3317-3331
Linkages between DOC availability and soil heterotrophic respiration
Three mechanisms could lead to lower amount of bioavailable dissolved organic C (DOC) for
the microbial community (Kopáček et al., 2013)
(1) Increased abundance of N for plant uptake, causing lower C allocation to plant roots
(2) Chemical suppression of DOC solubility by soil acidification
(3) Enhanced mineralisation of DOC due to increased abundance of electron acceptors in the
form of sulphate and nitrate - in anoxic soil micro-sites.
CO2 measurements
Treatment addition
Week 1
Treatment addition
Treatment addition
Week 2
Week 3
Leachate analysis
Leachate analysis
Week 4
Leachate analysis
Soil analysis
Soil analysis
800 ueq L-1
Control
H2SO4 HCl
NaOH
NaCl
Linkages between DOC availability and soil heterotrophic respiration
Linkages between DOC availability and soil heterotrophic respiration
200
soilwater DOC
180
160
1st treat
2nd treat
3rd treat
140
mg/L
120
100
80
60
40
20
0
Ctrl
H2SO4
HCl
NaOH
NaCl
Solution applications had immediate effect on DOC concentration in soil water.
Linkages between DOC availability and soil heterotrophic respiration
Standardized soil respiration (CO2 flux)
1.3
1.2
NaOH
1.1
1.0
NaCl
0.9
H2SO4
0.8
1st treatment
0.7
1
49
97
145
2nd treatment
193
Hour
241
3rd treatment
289
337
Solution applications had immediate effect on DOC concentration in soil water and on soil
respiration. In the end of the experiment, alkaline solution enhanced soil respiration by 20%
compared to control, whereas acid treatment suppressed soil respiration by 15% compared
to control. Neutral treatment has only short-term effect (suppression) on soil respiration.
Conclusions
• It appears that past acidification caused the suppression of decomposition leading to the
accumulation of a large pool of organic matter on the forest floor. The alleviation of this
acidification pressure over the last two decades appears to have triggered the remobilisation
of the soil C pool.
•Declining S deposition appears able to explain a large part of observed DOC trends.
• Therefore, rising DOC in well studied areas (Europe, USA) should not be misconstrued as
evidence of rising DOC in unmonitored waters globally.
- threats of widespread destabilization of terrestrial carbon reserves by gradual
rises in air temperature or CO2 concentration may have been overstated in
those areas.
• Past acid conditions may have reduced decomposition rates, allowing a pool of relatively
labile organic matter to accumulate, from which DOC is generated as acidity decreases.
Soil Carbon Cycle
Plants
3
CO2
litter C
1
Soil Organic
Matter
(SOM)
respiration
Decomposer
Turnover
4
2
Dissolved
Organic
Material
(DOM)
DOC DON
Tree ring increments (forest productivity) over
the last century
Mean N deposition (bulk) 1994-2013
13 kg N/ha/year
Mean S deposition (bulk) 1994-2013
10 kg S/ha/year
Mean N-NO3 leaching 1994-2013
6 kg N/ha/year
Elevation
1000 - 1300 m a.s.l.
Precipitation
≈1750 mm
Tree ring width index
250
200
10thdata
percentile
Tree line
since 1690
(V. Treml, unpublished results)
n = ≈100
median
90th percentile
150
100
50
0
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Conclusions
• It appears that past acidification caused the suppression of decomposition leading to the
accumulation of a large pool of organic matter on the forest floor. The alleviation of this
acidification pressure over the last two decades appears to have triggered the remobilisation
of the soil C pool.
•Declining S deposition appears able to explain a large part of observed DOC trends.
• Therefore, rising DOC in well studied areas (Europe, USA) should not be misconstrued as
evidence of rising DOC in unmonitored waters globally.
- threats of widespread destabilization of terrestrial carbon reserves by gradual
rises in air temperature or CO2 concentration may have been overstated in
those areas.
• Past acid conditions may have reduced decomposition rates, allowing a pool of relatively
labile organic matter to accumulate, from which DOC is generated as acidity decreases.
• Altered soil respiration is probably a direct result of DOC bioavailability for microbes under
different treatments, rather then direct pH effect on soil microbial communities.
• Growth reduction of conifer forests in Central Europe has been observed between the
1960s and 1980s.
• During recent decades a distinct increasing growth trends were observed. This trend might
only be explained if climate, fertilization by N-deposition, and the strong reduction of SO2
pollution are taken into account.
Modelling nitrogen with MAGIC
MAGIC (Model for Acidification of Groundwater In Catchments)
-Developed to predict the long-term effects of acidic deposition on surface water
chemistry
-Model simulates soil and surface water chemistry in response to changes in drivers such
as deposition of S and N, land use practices, climate…
- As sulphate concentrations have decreased, in response to the decreased S deposition,
nitrate (NO3) has become increasingly important. In acid soils much of the NO3 leached
from soil is accompanied by the acid cations H+ and inorganic aluminium (Ali)
-In the early versions of MAGIC (version 1-5) retention of N was calculated empirically as
a fraction of N deposited from input-output budgets
-Later on fraction N retained was described as a function of the N richness of the
ecosystem (soil C/N ratio in this case) – version 7
Soil C/N and N leaching - empirical evidence
Soil C/N seems to be a good predictor
of N leaching on a spatial scale
Lovett et al., Ecosystems (2002) 5: 712-718
Oulehle et al. Ecosystems (2008) 11: 410–425
Some limitations
- Soil C/N is vegetation specific
- C/N ratio does not necessarily reflect the N-richness of the actively cycling
component of the organic matter
- C/N ratio does not appear to be useful in understanding relatively short-term
changes in N dynamics
- „hard“ to detect changes in soil C/N under field conditions
Modelling nitrogen with MAGIC
Alternative formulation of N retention in new version of MAGIC (MAGIC v7ext) is based
directly on the microbial processes which determine the balance of N mineralization and
immobilization.
Conceptually developed by Jack Cosby
- Inorganic N enters the model as
deposition (wet and dry)
- Time series of plant litter and N fixation
(litter C and N) are external inputs to
SOM. At each time step, decomposers
process some of the C and N content of
SOM (FC1 and FN1). A portion of this C
and N turnover returns to the SOM as
decomposer biomass (FC2 and FN2), while
the remainder is lost from SOM as CO2
and NH4 (FC3 and FN3) or as DOC and
DON (FC4 and FN4).
Modelling nitrogen with MAGIC
• Preliminary testing of MAGIC performance in monthly time step
• Soil organic matter decomposition and N uptake driven by changes in soil
temperature – Q10 fce (calculated externaly)
• potential application in climate change scenario assessment
Čertovo lake
Soil temp
Air temp
6000
20
C mmol m-2 month-1
15
°C
10
5
0
-5
5000
140
C decomp (Q10=3)
120
N uptake (Q10=4)
100
4000
80
3000
60
2000
40
1000
20
-10
-15
2003
0
1997
2004
2005
2006
0
2000
2003
2006
2008
2011
N mmol m-2 month-1
25
Modelling nitrogen with MAGIC
45
N-NO3 (mmol m-2 month-1)
Čertovo Lake inlet
30
15
0
1997
1999
2001
2003
2005
2007
2009
Conclusions
• It appears that past acidification caused the suppression of decomposition leading to the
accumulation of a large pool of organic matter on the forest floor. The alleviation of this
acidification pressure over the last two decades appears to have triggered the remobilisation
of the soil C pool.
•Declining S deposition appears able to explain a large part of observed DOC trends.
• Therefore, rising DOC in well studied areas (Europe, USA) should not be misconstrued as
evidence of rising DOC in unmonitored waters globally.
- threats of widespread destabilization of terrestrial carbon reserves by gradual
rises in air temperature or CO2 concentration may have been overstated in
those areas.
• Past acid conditions may have reduced decomposition rates, allowing a pool of relatively
labile organic matter to accumulate, from which DOC is generated as acidity decreases.
• Altered soil respiration is probably a direct result of DOC bioavailability for microbes under
different treatments, rather then direct pH effect on soil microbial communities.
• Growth reduction of conifer forests in Central Europe has been observed between the
1960s and 1980s.
• During recent decades a distinct increasing growth trends were observed. This trend might
only be explained if climate, fertilization by N-deposition, and the strong reduction of SO2
pollution are taken into account.
• Acidity changes in forest ecosystems might have a strong confounding influence on
ecosystem sensitivity to eutrophication, with acidification accelerating N saturation (nitrate
leaching), and recovery potentially resulting in reversion to N limitation (nitrate retention).
Conclusions
• It appears that past acidification caused the suppression of decomposition leading to the
accumulation of a large pool of organic matter on the forest floor. The alleviation of this
acidification pressure over the last two decades appears to have triggered the remobilisation
of the soil C pool.
•Declining S deposition appears able to explain a large part of observed DOC trends.
• Therefore, rising DOC in well studied areas (Europe, USA) should not be misconstrued as
evidence of rising DOC in unmonitored waters globally.
- threats of widespread destabilization of terrestrial carbon reserves by gradual
rises in air temperature or CO2 concentration may have been overstated in
those areas.
Děkuji za
pozornost
• Past acid conditions may have reduced decomposition rates, allowing a pool of relatively
labile organic matter to accumulate, from which DOC is generated as acidity decreases.
• Altered soil respiration is probably a direct result of DOC bioavailability for microbes under
different treatments, rather then direct pH effect on soil microbial communities.
• Growth reduction of conifer forests in Central Europe has been observed between the
1960s and 1980s.
• During recent decades a distinct increasing growth trends were observed. This trend might
only be explained if climate, fertilization by N-deposition, and the strong reduction of SO2
pollution are taken into account.
• Acidity changes in forest ecosystems might have a strong confounding influence on
ecosystem sensitivity to eutrophication, with acidification accelerating N saturation (nitrate
leaching), and recovery potentially resulting in reversion to N limitation (nitrate retention).
MODELOVÁNÍ
Oulehle F., Cosby B.J., Wright R.F., Hruška J., Kopáček J., Krám P., Evans C.D., and Moldan F. (2012). Modeling soil
nitrogen: the MAGIC model with nitrogen retention linked to carbon turnover using decomposer dynamics.
Environmental Pollution 165: 158-166.
Rowe E.C., Tipping E., Posch M., Oulehle F., Cooper D.M., Jones T.G., Burden A., Hall J., Evans C.D. (2014).
Predicting nitrogen and acidity effects on long-term dynamics of dissolved organic matter. Environmental
Pollution184: 271-282.
ACIDIFKACE POVRCHOVÝCH VOD
Oulehle F., Chuman T., Majer V., Hruška J. (2013). Chemical recovery of acidified Bohemian lakes between 1984 and
2012: The role of acid deposition and bark beetle induced forest disturbance. Biogeochemistry 116 (1-3): 83-101.
ROZPUŠTĚNÝ ORGANICKÝ UHLÍK
Oulehle F., Jones T.G., Burden A., Cooper M.D.A., Lebron I., Zieliński P., Evans C.D. (2013). Soil-solution partitioning
of DOC in acid organic soils: Results from a UK field acidification and alkalization experiment. European Journal of
Soil Science 64 (6): 787-796.
Oulehle F. and Hruška J. (2009) Rising trends of dissolved organic matter in drinking-water reservoirs as a result of
recovery from acidification in the Ore Mts., Czech Republic. Environmental Pollution 157: 3433-3439.
Evans C.D., Jones T.G., Burden A., Ostle N., Zielinski P., Cooper M.D.A., Peacock M., Clark J.M., Oulehle F., Cooper
D., Freeman C. (2012). Acidity controls on dissolved organic carbon mobility in organic soils. Global Change
Biology 18: 3317-3331.
VZTAH MEZI ACIDIFIKACÍ A C A N KOLOBĚHEM V LESNÍCH PŮDÁCH
Oulehle F., Evans C.D., Hofmeister J., Krejci R., Tahovska K., Persson T., Cudlin P., Hruska J. (2011) Major changes
in forest carbon and nitrogen cycling caused by declining sulphur deposition. Global Change Biology 17: 31153129.
Kopáček J., Cosby B.J., Evans C.D., Hruška J., Moldan F., Oulehle F., Šantrůčková H., Tahovská K., Wright R.F.
(2013). Nitrogen, organic carbon and sulphur cycling in terrestrial ecosystems: Linking nitrogen saturation to carbon
limitation of soil microbial processes. Biogeochemistry 115 (1-3): 33-51.
Tahovská K., Kaňa J., Bárta J., Oulehle F., Richter A., Šantrůčková H. (2013). Microbial N immobilization is of great
importance in acidified mountain spruce forest soils. Soil Biology & Biochemistry 59: 58-71