Emissions of Volatile Organic Compounds by Plants Carbon
Metabolism and Atmospheric Chemistry Kolby Jardine Amazon-PIRE
Field Course June 2010
Slide 2
Composition of the Atmosphere Gases
Slide 3
What are VOCs? Atmospheric Concentrations < 20 ppb
Slide 4
Dominant primary VOC sources in the Atmosphere Biomass Burning
Urban/Industrial Emissions Biogenic Emissions VOC: volatile organic
compound e.g. hydrocarbons
Slide 5
From www.igac.noaa.gov Atmospheric Impacts of VOCs 1)Climate
2)Air Quality
Slide 6
Why the interest in BVOCs? Reactive Aerosols Biogenic VOCs
Anthropogenic VOCs
Slide 7
Organic Aerosol TRACE GASES oxidize Ozone H 2 CO CO CH 4
Secondary Organic Aerosol Isoprene Monoterpenes Sesquiterpenes
Oxygenated VOC
Slide 8
Simplified Catalytic Cycle of Tropospheric Ozone Production
Players: VOC: volatile organic compounds NO x : nitrogen oxides RO
2: peroxy radicals hv: radiation RO 2 (HO 2 ) ROVOC emissions OH
O2O2 Fuel NONO 2 NO x emissions OH HNO 3 O2O2 hv Ozone Catalyst
fossil fuel combustion biomass burning (soil, lightning) O*
Slide 9
How Many Species are Produced during the Oxidation of
Hydrocarbons? Aumont et al., ACPD, 2005 Heptane: 10 5 10 6
intermediates >10 6 reactions Isoprene: 10 4 intermediates
>10 4 reactions O 3 + hv O( 1 D) + O 2 O( 1 D) + H 2 O OH + OH
OH The Detergent of the Atmosphere During the 18th century
engineers already knew that coal combustion would release CO as a
toxic substance. They estimated that within ~1000-2000 years the
atmosphere would fill up with high enough levels of CO so that any
life on the planet would die! Luckily this wont happen due to the
presence of OH!
Slide 10
Tower-based flux meas. systems Years Days Hours TIME SCALE
SPATIAL SCALE Leaf Canopy LandscapeRegional/global Enclosure flux
meas. systems Analysis using ambient concentrations, isotopes and
oxidation products Satellite data (e.g. HCHO) Aircraft and
blimp-based flux measurement systems Process studies Tools for
Investigating Trace Gas Fluxes Seconds Regional
Characterization
Slide 11
Measurement techniques
Slide 12
Amazon VOCs Emitted from Vegetation >1000 compounds
identified tropics: 100s species / ha Image from
ksuweb.kennesaw.edu
Slide 13
Ray Fall 1999 Volatile Metabolite Emissions from Plants
1)Environmental Stresses (desiccation, UV light, oxidants) 2)
Reproduction and growth 3) Phytohormones (semiochemicals) 4)
Biological stresses (herbivores) 5) Primary carbon and energy
metabolism
Slide 14
Primary Carbon Metabolism in Plants RUBISCO PEP carboxylase
Respiration Photorespiration Fermentation CO 2 Photosynthesis Are
VOC emissions related to these processes?
Slide 15
Pyruvic acid; the link between primary and secondary carbon
metabolism Ethanol Acetaldehyde Acetic Acid Pyruvic Acid Acetone
Isoprene Sesquiterpenes Monoterpenes
Slide 16
Slide 17
Slide 18
Response of Isoprene Emissions to Temperature Guenther et al.
empirical algorithms
Slide 19
Response of Isoprene Emissions to Light
Slide 20
Response of Isoprene Emissions to Atmospheric CO2
Concentrations
Slide 21
F = g*C, where C = [isoprene] i [isoprene] a atmosphere Leaf
[isoprene] a production [isoprene] i [isoprene] a production
[isoprene] i [isoprene] a production [isoprene] i
Slide 22
F = g*C, where C = [AA] i [AA] a [AA] a atmosphere Leaf
consumption production [AA] i consumption production [AA] i
Slide 23
Summary of Biosphere-Atmosphere Feedbacks From Pasifico et al.,
2009
Slide 24
Thanks! Paulo Artaxo (University of Sao Paulo) Trina Shartsis
(University of Arizona) Scott Saleska (University of Arizona)
Travis Huxman (University of Arizona) Angie Jardine (University of
Arizona) Alex Guenther (NCAR) Thomas Karl (NCAR) Peter Harley
(NCAR)
