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On the variability of the ecosystem response to elevated atmospheric CO2 across spatial and temporal scales at the Duke Forest FACE experiment

On the variability of the ecosystem response to elevated atmospheric CO2 across spatial and temporal scales at the Duke Forest FACE experiment
On the variability of the ecosystem response to elevated atmospheric CO2 across spatial and temporal scales at the Duke Forest FACE experiment
While the significance of elevated atmospheric CO2 concentration on instantaneous leaf-level processes such as photosynthesis and transpiration is rarely disputed, its integrated effect at ecosystem level and at long-time scales remains a subject of debate. In part, the uncertainty stems from the inherent leaf-to-leaf variability in gas exchange rates. By combining 10 years of leaf gas exchange measurements collected during the Duke Forest Free Air CO2 Enrichment (FACE) experiment and three different leaf-scale stomatal conductance models, the leaf-to-leaf variability in photosynthetic and stomatal conductance properties is examined. How this variability is then reflected in ecosystem water vapor and carbon dioxide fluxes is explored by scaling up the leaf-level process to the canopy using model calculations. The main results are: (a) the space-time variability of the photosynthesis and stomatal conductance response is considerable as expected. (b) Variability of the calculated leaf level fluxes is dependent on both the meteorological drivers and differences in leaf age, position within the canopy, nitrogen and CO2 fertilization, which can be accommodated in model parameters. (c) Meteorological variability is playing the dominant role at short temporal scales while parameter variability is significant at longer temporal scales. (d) Leaf level results do not necessarily translate to similar ecosystem level responses due to indirect effects and other compensatory mechanisms related to long-term vegetation dynamics and ecosystem water balance.
0168-1923
367-383
Paschalis, Athanasios
e7626e9f-172b-4da2-882c-bddb219f3fb6
Katul, Gabriel G.
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Fatichi, Simone
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Palmroth, Sari
fed9ca64-1d85-4946-b845-e22bb6a2241c
Way, Danielle
c7795749-c9c9-4669-9e27-7d6aac3be593
Paschalis, Athanasios
e7626e9f-172b-4da2-882c-bddb219f3fb6
Katul, Gabriel G.
5f0cb2ab-2d91-4cc4-9ac2-e5c2eaf928f9
Fatichi, Simone
2a12468d-8094-495b-922d-4d00aa0afb11
Palmroth, Sari
fed9ca64-1d85-4946-b845-e22bb6a2241c
Way, Danielle
c7795749-c9c9-4669-9e27-7d6aac3be593

Paschalis, Athanasios, Katul, Gabriel G., Fatichi, Simone, Palmroth, Sari and Way, Danielle (2017) On the variability of the ecosystem response to elevated atmospheric CO2 across spatial and temporal scales at the Duke Forest FACE experiment. Agricultural and Forest Meteorology, 232, 367-383. (doi:10.1016/j.agrformet.2016.09.003).

Record type: Article

Abstract

While the significance of elevated atmospheric CO2 concentration on instantaneous leaf-level processes such as photosynthesis and transpiration is rarely disputed, its integrated effect at ecosystem level and at long-time scales remains a subject of debate. In part, the uncertainty stems from the inherent leaf-to-leaf variability in gas exchange rates. By combining 10 years of leaf gas exchange measurements collected during the Duke Forest Free Air CO2 Enrichment (FACE) experiment and three different leaf-scale stomatal conductance models, the leaf-to-leaf variability in photosynthetic and stomatal conductance properties is examined. How this variability is then reflected in ecosystem water vapor and carbon dioxide fluxes is explored by scaling up the leaf-level process to the canopy using model calculations. The main results are: (a) the space-time variability of the photosynthesis and stomatal conductance response is considerable as expected. (b) Variability of the calculated leaf level fluxes is dependent on both the meteorological drivers and differences in leaf age, position within the canopy, nitrogen and CO2 fertilization, which can be accommodated in model parameters. (c) Meteorological variability is playing the dominant role at short temporal scales while parameter variability is significant at longer temporal scales. (d) Leaf level results do not necessarily translate to similar ecosystem level responses due to indirect effects and other compensatory mechanisms related to long-term vegetation dynamics and ecosystem water balance.

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Accepted/In Press date: 12 September 2016
e-pub ahead of print date: 17 September 2016
Published date: 15 January 2017
Organisations: Water & Environmental Engineering Group

Identifiers

Local EPrints ID: 400572
URI: http://eprints.soton.ac.uk/id/eprint/400572
ISSN: 0168-1923
PURE UUID: c265aa62-646c-4623-a3f2-b15c6b6fcc51
ORCID for Athanasios Paschalis: ORCID iD orcid.org/0000-0003-4833-9962

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Date deposited: 19 Sep 2016 13:01
Last modified: 15 Mar 2024 05:54

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Contributors

Author: Athanasios Paschalis ORCID iD
Author: Gabriel G. Katul
Author: Simone Fatichi
Author: Sari Palmroth
Author: Danielle Way

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