Ecosystem-scale trade-offs between impacts of ozone and reactive nitrogen Ed Rowe, Felicity Hayes,...
If you can't read please download the document
Ecosystem-scale trade-offs between impacts of ozone and reactive nitrogen Ed Rowe, Felicity Hayes, Kasia Sawicka, Gina Mills, Laurence Jones, Filip Moldan,
Ecosystem-scale trade-offs between impacts of ozone and
reactive nitrogen Ed Rowe, Felicity Hayes, Kasia Sawicka, Gina
Mills, Laurence Jones, Filip Moldan, Sereina Bassin, Netty van Dijk
& Chris Evans EGU, Vienna, 13th April 2015
Slide 2
Nitrogen is an acidifying pollutant Giant Mountains, Czech
Republic, 2005 UK NO x emissions UK NH 3 emissions RoTAP report,
CEH, 2012 Temporal deposition sequence from GANE project (Fowler et
al 2004 WASP:Focus 4: 9-23) UK SO 2 emissions Many systems are
recovering from acid rain But reductions in reactive-nitrogen (NO
x, NH y ) emissions have been small, compared to reductions in S
emissions
Slide 3
Nitrogen is also a fertiliser End of the fertiliser bag,
Mutare, Zimbabwe, 2002 Ammonium nitrate delivery, Gwynedd, UK, 2006
Current Legislated [N] Emissions Maximum Feasible [N] Reduction de
Vries & Posch (2011) Env Poll 159: 2289-2299 Additional
European C sequestration due to N pollution
Slide 4
not good for species that need ground-level light Hodgson et
al. (2014) Functional Ecology 28: 1284-1291. more N -->
increasing productivity ground-level shade litterfall Drosera
rotundifolia Urtica dioica Lotus corniculatus
Slide 5
N deposition reduces species-richness Acid grassland, UK
Heathland, UK Stevens et al. (2004) Science 303: 1876-1879 Maskell
et al. (2010) Global Change Biol.16: 671679 kg N ha -1 y -1 Number
of species 0 5 30 40 0 45 Number of species
Slide 6
Global reactive-N deposition Dentener et al. 2006 Global
Biogeochem Cycles 20: GB4003 mg N m -2 yr -1 For terrestrial
ecosystems, land-use change probably will have the largest effect
[on biodiversity], followed by climate change, nitrogen deposition,
biotic exchange, and elevated carbon dioxide concentration. Sala et
al 2000, Science 287: 1770-1774 kg N ha -1 yr -1 60 20 5 1 0.1
Slide 7
Predicting effects of N and S (MADOC) N14C: Tipping et al. 2012
Ecological Modelling 247:11-26 VSD: Posch & Reinds 2009 Env
Modelling and Software 24: 329-340 DyDOC: Michalzik et al. 2003
Biogeochemistry 66, 241-264 N14C: vegetation growth and soil
organic matter development VSD: cation exchange and pH DyDOC:
dissolution of organic matter MADOC: dynamic integration, allowing
feedback between pH and DOC
Predicting effects on plant species and biodiversity Floristic
response MultiMOVE Vegetation and soil biogeochemistry MADOC Total
N deposition Indicators of environmental conditions e.g. pH,
mineral N, light Habitat suitability for individual species Other
drivers Biogeochemistry Plant ecology Quantity Model Key: Other
drivers Rhynchospora alba Smart et al. 2010 J Veg Sci 21: 643:656
Henrys et al. New J Bot in prep.
Slide 10
Summarising effects on biodiversity Rowe et al. (submitted)
Ecological Indicators
Slide 11
How will ozone pollution interact? Ozone in the stratosphere
protects the planet from ultraviolet radiation but tropospheric
i.e. ground-level ozone is a problem. Formed in reactions involving
nitrogen oxides and Volatile Organic Compounds European NO x and
VOC emissions controls decreasing peak concentrations Hemispheric
transport increasing background concentrations Effects on human
health Damage to plants increasing crop losses Photo: Gina Mills
Tropospheric ozone formation diagram:
http://keutsch.chem.wisc.edu/
Slide 12
Ozone effects supported by evidence 1.Decreasing plant
productivity (NPP) at greater ozone concs. reduced productivity,
reduced carbon inputs 2.Reduced translocation of N out of senescing
leaves at greater ozone concs. more potential for N loss e.g.
leaching, N 2 O
Slide 13
Ozone effects added into MADOC 1.Reduction in NPP with
increasing ozone concentration
Slide 14
Ozone effects added into MADOC 2. Reduced translocation of N
out of senescing leaves with increasing ozone conc.
Responses to N treatments Whim Moss Scotland heath exposed to
dry NH 3 or wet NaNO 3 or wet NH 4 Cl Symbols = Modelled Lines =
observed
Slide 17
Responses to N treatments Grdsjn Sweden coniferous forest
subcatchments Treatments: Control; +40 kg N ha -1 yr -1 (wet NH 4
NO 3 ) Symbols = Modelled Lines = observed
Slide 18
Responses to N x O 3 treatments AlpFlix Switzerland Alpine
grassland, extremely low N deposition, but chronically exposed to
ozone Experimental responses (circles): Strong productivity
response to N No significant productivity response to ozone Bassin
et al (2007) New Phytologist 175, 523-534. Modelled responses
(lines): responses to N and ozone negative interaction (ozone
limits response to N, and vice versa) Symbols = Modelled Lines =
observed
Slide 19
Sensitivity of productivity to N and Ozone i.e. ozone reduces
plant productivity by a greater proportion at greater N deposition
Could it be said that ozone pollution moderates the effects of N
pollution?
Slide 20
Direct ozone effects on biodiversity Hayes et al. (unpublished)
Effect of ozone exposure on cover of Campanula rotundifolia in
calcareous grassland
Slide 21
Conclusions We need more ecosystem-level experiments on N-ozone
interactions Simulations are the best available basis for assessing
ecosystem effects of O 3 and N N is likely to increase productivity
benefits for agriculture and forestry, C storage disbenefits for
biodiversity Ozone is likely to decrease productivity benefits for
biodiversity? likely to be outweighed by direct adverse effects of
O 3 N and ozone together are likely to increase soil N cycling
rates disbenefits due to N leaching and NOx emissions
Acknowledgements This work was funded by the UK Government (Defra)
and by the European Union (FP7 ECLAIRE project)