Book contents
- Frontmatter
- Contents
- Preface
- List of symbols
- 1 The general nature of biosphere-atmosphere fluxes
- 2 Thermodynamics, work, and energy
- 3 Chemical reactions, enzyme catalysts, and stable isotopes
- 4 Control over metabolic fluxes
- 5 Modeling the metabolic CO2 flux
- 6 Diffusion and continuity
- 7 Boundary layer and stomatal control over leaf fluxes
- 8 Leaf structure and function
- 9 Water transport within the soil-plant-atmosphere continuum
- 10 Leaf and canopy energy budgets
- 11 Canopy structure and radiative transfer
- 12 Vertical structure and mixing of the atmosphere
- 13 Wind and turbulence
- 14 Observations of turbulent fluxes
- 15 Modeling of fluxes at the canopy and landscape scales
- 16 Soil fluxes of CO2, CH4, and NOx
- 17 Fluxes of biogenic volatile compounds between plants and the atmosphere
- 18 Stable isotope variants as tracers for studying biosphere-atmosphere exchange
- References
- Index
- Plate Section
17 - Fluxes of biogenic volatile compounds between plants and the atmosphere
Published online by Cambridge University Press: 05 June 2014
- Frontmatter
- Contents
- Preface
- List of symbols
- 1 The general nature of biosphere-atmosphere fluxes
- 2 Thermodynamics, work, and energy
- 3 Chemical reactions, enzyme catalysts, and stable isotopes
- 4 Control over metabolic fluxes
- 5 Modeling the metabolic CO2 flux
- 6 Diffusion and continuity
- 7 Boundary layer and stomatal control over leaf fluxes
- 8 Leaf structure and function
- 9 Water transport within the soil-plant-atmosphere continuum
- 10 Leaf and canopy energy budgets
- 11 Canopy structure and radiative transfer
- 12 Vertical structure and mixing of the atmosphere
- 13 Wind and turbulence
- 14 Observations of turbulent fluxes
- 15 Modeling of fluxes at the canopy and landscape scales
- 16 Soil fluxes of CO2, CH4, and NOx
- 17 Fluxes of biogenic volatile compounds between plants and the atmosphere
- 18 Stable isotope variants as tracers for studying biosphere-atmosphere exchange
- References
- Index
- Plate Section
Summary
The nose can reveal much qualitative information about the release of organic volatiles by plants, but since it is preferentially sensitive to certain terpenes. . . and rather insensitive to others. . . analyses with a gas chromatograph are needed to obtain a quantitative picture of the volatile organics present in the air at all times. Thus we easily detect the aromaticity of a deciduous forest in autumn, and especially the sweet odor of the leaf litter on the forest floor, and we can tell a coniferous forest at a distance. But we are unprepared for the fact that an oak forest produces virtually as many aromatics as a pine forest, only of a lower odor level.
Rasmussen and Went (1965)Plants not only exchange inorganic C with the atmosphere, but also organic C in the form of a broad range of biogenic volatile organic compounds (BVOCs). The magnitude of the global BVOC flux is small compared to the global photosynthetic CO2 flux: ~ 2 Pg of C contained in annual BVOC emissions (including CH4 and CO) compared to global gross primary productivity, which is ~ 120 Pg of CO2. However, the BVOC flux is critical to understanding chemical reactions that occur in the atmosphere, especially those that produce important oxidant compounds, such as ozone, those that determine the oxidation rate of important greenhouse gases, such as methane, and those that determine the production of organic aerosol particles, which affect the earth’s radiation budget. Scientists did not recognize that the emission of compounds from vegetation could have such an important impact on atmospheric chemistry until the mid 1960s when researchers such as Rei Rasmussen and Fritz Went began collecting air samples in remote locations, far from the influences of urban pollution. This effort to describe the volatile chemical “fingerprints” of natural ecosystems revealed the presence of a large outward flux of reactive compounds that had previously been unidentified. For example, as reflected in the quote above, careful analysis using gas chromatography revealed the presence of reactive isoprene and other terpenes in an oak forest, which would have been undiscovered if left to detection by the human nose alone. Once these observations started to accumulate, it became clear that biogenic sources of reactive compounds were even more important than anthropogenic sources in their potential to catalyze oxidative photochemistry and, in many cases, control the overall oxidative capacity of the troposphere.
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- Terrestrial Biosphere-Atmosphere Fluxes , pp. 395 - 414Publisher: Cambridge University PressPrint publication year: 2014
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