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Impacts of acid rain and ozone on vegetation in the
Greater Mekong Sub region
Lisa Emberson
Patrick Büker, Tim Morrissey, Kevin Hicks, Johan Kuylenstierna,
Steve Cinderby, Mike Ashmore, David Simpson, Juha-Pekka
Tuovinen, Mark Zunckel, Miles Sowden, Barabara Badu,
Vanessa Walsh
[email protected]
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Modelling methods
- Experimental methods
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Modelling methods
- Experimental methods
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
Why worry about air pollution impacts on vegetation ?
Air pollutant
Gas, particle, aerosol, solute
Stomatal
flux/uptake/deposition
Direct
Non-stomatal
flux/uptake/deposition
External plant
surfaces
Indirect
Soil
[email protected]
Why worry about air pollution impacts on vegetation ?
Pollutant
Impact mode
Impact
Scale
Ozone (O3)
Direct (stomates)
Visible injury, growth & yield reductions,
chemical quality
Regional
Sulphur dioxide
(SO2)
Direct (stomates
& cuticle)
* Visible injury, growth & yield reductions
Local
Indirect
Soil acidification (growth & yield reductions)
Regional
Direct (stomates)
* Growth & yield reductions
Local
Indirect
Soil acidification (growth & yield reductions)
Regional
Hydrogen Fluorides
(HF)
Direct (stomates
& cuticle)
Visible injury, growth & yield reductions.
Fluorosis in grazing animals
Local
Suspended
Particulate Matter
(SPM)
Direct
**Phytotoxicity, abrasive action, reduced
light transmission, occlusion of stomates
Local /
Regional
Nitrogen oxides
(NOx)
* At low concentrations can stimulate growth via fertilization effect
** Dependant upon chemical composition of particles
[email protected]
Why worry about air pollution impacts on vegetation ?
Pollutant
Impact mode
Impact
Scale
Ozone (O3)
Direct (stomates)
Visible injury, growth & yield reductions,
chemical quality
Regional
Sulphur dioxide
(SO2)
Direct (stomates
& cuticle)
* Visible injury, growth & yield reductions
Local
Indirect
Soil acidification (growth & yield reductions)
Regional
Direct (stomates)
* Growth & yield reductions
Local
Indirect
Soil acidification (growth & yield reductions)
Regional
Hydrogen Fluorides
(HF)
Direct (stomates
& cuticle)
Visible injury, growth & yield reductions.
Fluorosis in grazing animals
Local
Suspended
Particulate Matter
(SPM)
Direct
**Phytotoxicity, abrasive action, reduced
light transmission, occlusion of stomates
Local /
Regional
Nitrogen oxides
(NOx)
* At low concentrations can stimulate growth via fertilization effect
** Dependant upon chemical composition of particles
[email protected]
Why worry about air pollution impacts on vegetation ?
Decline of Veitch’s silver fir and maries fir. Japan
(courtesy of T. Izuta)
Annual average
pH of P
Rodhe et al. 2002
Soil sensitivity to
acidic deposition
Kuylenstierna et al. 2001
Observational evidence of soil acidification in
China similar to Europe
The decrease in soil pH between
1927 to 1982-83 in a beech and
spruce forest in southern Sweden
(Hallbäcken and Tamm, 1985)
Change in soil pH 1960 – 1994
at Zhurongfeng in S. China
Dai et al. 1998
No real evidence in other parts of Asia
[email protected]
Why worry about air pollution impacts on vegetation ?
O3 injury to rice, Pakistan
(courtesy of A. Wahid)
Current surface ozone in 2000
Europe
United states
South East Asia
36.6 ppb ± 4.2
38.7 ppb ± 4.9
31.5 ppb ± 4.4
Dentener et al. (2006)
Δ in surface ozone between 2000 and 2030
current legislation scenario
Europe
United states
South East Asia
CLE2000 – CLE2030
+1.8 ± 1.5
+1.3 ± 2.4
+3.8 ± 0.7
Dentener et al. (2006)
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Modelling methods – Acid Deposition
- Experimental methods
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
What methods exist to estimate risk?
1. Critical Load approach: deposition compared to threshold
(CL)
2. Dynamic models – limited application except in China for
some sites
[email protected]
Exceedance of critical loads a static
expression of risk but is it real?
time dimension issue: acidification has not occurred for
long enough for clear impacts to be seen?
Estimated exceedance of acidification CL of S only (Kuylenstierna et al.
2000)
[email protected]
“Serious acidification effects not likely to occur in next
few decades in Asia except in China”
Henning Rodhe
[email protected]
Estimates time development of acidification as a function of continued
acidic deposition and variation in soil sensitivity over time
Hicks et al. in prep
[email protected]
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Modelling methods
- Experimental methods – surface ozone
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
Assessing O3 impacts to species/ cultivars
Response
Dose
Experimental Methods
Disturbance
•
•
•
•
•
Controlled exposure
Free Air Concentration Enrichment (FACE)
Temporary chambers
Open Top Chambers
Solardomes
Indoor fumigation chambers / glasshouses
• individual pollutants & pollutant combinations
• establish dose response relationships
• pollutant interactions with other stresses
Experimental Methods
Disturbance
•
•
•
•
•
Controlled exposure
Free Air Concentration Enrichment (FACE)
Temporary chambers
Open Top Chambers
Solardomes
Indoor fumigation chambers / glasshouses
• individual pollutants & pollutant combinations
• establish dose response relationships
• pollutant interactions with other stresses
Assessing O3 impacts to species/ cultivars
Response
Yield
Nutritional quality
Visible injury
Dose
Concentration
Flux
Ozone characterization indices
100
12000
10000
80
8000
(53 ppb)
60
6000
40
4000
20
AOT40 (ppb.hrs)
Ozone conc (ppb)
Growing season
2000
0
0
0
50
100 150 200 250 300 350
Year day
* Annual mean
* 7hr growing season mean
* 7hr annual mean
* AOT40
7 hr mean dose response relationships for different species
including rice
cf. Wang & Mauzerall 2004
AOT40 relationship with wheat (Triticum aestivum) grain yield
(Fuhrer, 1996)
• Most robust AOT40 relationship
• 17 experiments, 6 countries, 10 growing seasons, 10 cultivars
• Critical Level : AOT40 of 3, 000 ppb.h. corresponding to 5% yield loss (99%
confidence) calculated over a 3 month growing period
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Experimental methods
- Modelling methods – surface ozone
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
How can we
estimate air
pollution impacts?
Dose-Response
Relationships
Modelling methods
3 month AOT40 simulations calculated with the MATCH model
Engardt pers. comm., Emberson et al. in press
Modelling methods
BUT
Are these areas identified as being at risk
from ground level ozone correct?
How good is the provisional risk assessment
modelling?
[email protected]
Modelling methods
How good is the regional
ozone concentration data?
What are the receptors most
at risk?
How well can AQGs protect
local species and varieties?
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Experimental methods
- Modelling methods
- Bio-monitoring methods – surface ozone
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
Bio-monitoring
Bio-monitoring and Chemical Protectant Studies
Buse et al. 2002/2003
• Established bio-indicator in Europe and North America
• Sensitive and resistant clones so can assess magnitude of air pollution
impacts on visible injury & biomass.
Bio-monitoring
Bio-monitoring and Chemical Protectant Studies
Structural formula for N-(2-(2-oxo-1imadazolidinyl)ethyl)-N’-phenylurea
abbreviated as EDU for ethylenediurea
Pakistan soybean cv. NARC-1 showing protective
effect of EDU at a roadside rural site in Lahore,
Pakistan (photo courtesy of A. Wahid)
EDU suppresses acute and chronic ozone injury on a variety of plants
under ambient O3 conditions (Godzik & Manning, 1998)
Bio-monitoring
All Bio-monitoring sites:
• Microloggers for ToC & RH % (30 min)
• Ozone passive samplers (2 week)
At select sites:
• Solar radiation, photosynthetically active radiation (PAR)
• Continuous ozone monitoring (hourly)
• Soil water content
•
Plant physiological parameters
e.g. Photosynthesis, stomatal conductance, leaf area index,
biochemical analysis (e.g. heavy metals, protein content….)
Bio-monitoring
RAPIDC Project funded by Sida
“Regional Air Pollution in Developing Countries”
Europe & North America
Provisional Risk Assessment
Clover clone bio-monitoring
e.g. Maize
staple Pulse
6 sites
EDU chemical protectant study
Southern Africa
South Africa, Botswana,
Zimbabwe, Mozambique
Zambia, Tanzania
South Asia
Wheat
Mung bean
5 sites
India, Pakistan, Sri Lanka,
Bangladesh, Nepal
Bio-monitoring
How good is the regional
ozone concentration data?
Passive samplers, O3
monitors
What are the receptors most
at risk?
Local agricultural expertise
How well can AQGs protect
local species and varieties?
Bio-monitoring evaluation of
damage occurring within and
outside provisionally
assessed risk areas
Bio-monitoring
How good is the regional
ozone concentration data?
Passive samplers, O3
monitors
What are the receptors most
at risk?
Local agricultural expertise
How well can AQGs protect
local species and varieties?
Bio-monitoring evaluation of
damage occurring within and
outside provisionally
assessed risk areas
Modelling methods
• Species type / cultivar
Climate
Precipitation patterns
Sunshine hours
Higher temperatures
Atmospheric humidity
Soil Moisture deficit
Dose modifiers
Flux
Vegetation sensitivity
Cropping patterns (growing season)
Pollutant dispersion
O3 formation
• Agronomic practices
Irrigation
Fertilizer
Breeding programmes (selecting increased / reduced crop sensitivity)
Assessing O3 impacts to species/ cultivars
AOTx
“Concentration”
AFstY
“Flux”
Surface Resistance
Rsur
Bio-monitoring
The Air Pollution Crop Effect
(APCEN) network
1. Advise on methodological development
2. To capacity build in the regions –provide technical
support to the bio-monitoring campaigns
3. To help in translation of science to policy
RAPIDC
Regional air pollution in developing countries
[email protected]
The APCEN Network
Region
Network
Members
Africa
8
Egypt, Kenya, Mozambique, South Africa,
Zimbabwe
43
India, Japan, Nepal, Pakistan, P.R. China,
Philippines, South Korea, Sri Lanka,
Taiwan, Thailand
16
Australia, Chile, Sweden, UK, USA
Asia
The Americas,
Europe and
Australia
Countries / regions represented
The APCEN network
2nd APCEN workshop held in Stellenbosch, South Africa 2006
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Experimental methods
- Modelling methods
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
Why worry about surface ozone concentrations ?
Δ in surface ozone between 2030clim change and 2030
current legislation scenario and projected 2030 climate
South East Asia
CLE2030c – CLE2030
-0.2 ± 0.6
Dentener et al. (2006)
Fuhrer et al. 2005
• FACE soybean (glycine max) experiment
• Increased O3 concentrations over two
growing seasons by 23 % - mimicking
projections for 2050
O3
• Resulted in 20% loss in seed yield
• Results suggest even greater losses
than those previously predicted by
closed chamber studies
O3
Morgan et al. 2006
Rsto = 1/ (gmax * fphen * flight * max {fmin, (ftemp * fVPD * fSWP)})
Generic gage function
1.2
Gmax mmol O3
m-2
s-1
Relative g
1
*
Phenology
0.8
0.6
0.4
gage_c
gage_b
0.2
gage_a
0
0
100
200
300
Year day
1
0.8
0.8
Relative g
Relative g
1
0.6
glight = 1 - exp (- * PAR)
0.4
0.2
0.6
T_min
0.4
0
0
500
1000
1500
2000
10
Irradiance (umol m-2 s-1 PAR)
Generic gVPD function
1
1
0.8
0.8
0.6
VPD_min
VPD_max
0.4
15
20
25
30
35
Temperature (oC)
40
Generic gSWP functions
Relative g
Relative g
T_max
T_opt
0.2
0
VPD
ToC
Generic gtemp function
Generic glight function
PAR
0.6
SMD
SWP_min
SWP_max
0.4
0.2
0.2
0
0
0
1
2
3
VPD (kPa)
4
5
-2
-1.5
-1
-0.5
Soil water potential (MPa)
0
Talk outline
Why worry about air pollution impacts on vegetation ?
Air pollution risk assessment methods for application in GMS :
- Experimental methods
- Modelling methods
- Bio-monitoring methods
Application incorporating additional stresses ?
- Climate change
- Hydrological stress
[email protected]
Future applications ?
1000.00
Modelled ozone concentrations across Southern Africa
0.00
-1000.00
-2000.00
100
80
-3000.00
60
40
-4000.00
-5000.00
-1000.00
0.00
1000.00
2000.00
Zunckel
et al 2004
3000.00
Future applications ?
Growing season length and risk of drought in southern Africa
PEt : AEt
Soil water
PEt & AEt
f(Ra, Rb, Rsto)
VPD & Net
radiation
Relative yield
P Ei
Drought related yield losses
O3 related yield losses
Compare ozone and drought stress to maize across region
Conclusions
Acid deposition may be a problem in the future in parts of south east Asia
O3 is likely to be already causing damage to crops and forests in the GMS ?
O3 concentrations are projected to increase relatively rapidly over the next 20
to 50 years in this region
As such, there is an urgent need to develop methods for O3 risk assessment
for the GMS region :
These methods can be founded on existing experimental and modelling
techniques which would ideally be supported by bio-monitoring evaluation
In addition, methodological selection and development should ensure
assessments can incorporate additional stresses such as climate change and
hydrological related stresses
[email protected]
Acknowledgements
This research is supported by Sida and
Defra
Related projects are also supported by the
EU and START PACOM.
[email protected]