Reconciling Top-Down and Bottom-Up Estimates of Ecosystem Respiration in a Mature Eucalypt Forest

Noh, NJ; Renchon, AA; Knauer, J; Haverd, V; Li, J; Griebel, A; Barton, CVM; Yang, J; Sihi, D; Arndt, SK; Davidson, EA; Tjoelker, MG; Pendall, E

Reconciling Top-Down and Bottom-Up Estimates of Ecosystem Respiration in a Mature Eucalypt Forest

Noh, NJ Renchon, AA Knauer, J Haverd, V Li, J Griebel, A

Barton, CVM Yang, J Sihi, D Arndt, SK Davidson, EA Tjoelker, MG Pendall, E

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Publisher:: AMER GEOPHYSICAL UNION
Publication Type:: Journal Article
Citation:: Journal of Geophysical Research: Biogeosciences, 2024, 129, (10)
Issue Date:: 2024-10-01

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Field	Value	Language
dc.contributor.author	Noh, NJ
dc.contributor.author	Renchon, AA
dc.contributor.author	Knauer, J
dc.contributor.author	Haverd, V
dc.contributor.author	Li, J
dc.contributor.author	Griebel, A https://orcid.org/0000-0002-4476-8279
dc.contributor.author	Barton, CVM
dc.contributor.author	Yang, J
dc.contributor.author	Sihi, D
dc.contributor.author	Arndt, SK
dc.contributor.author	Davidson, EA
dc.contributor.author	Tjoelker, MG
dc.contributor.author	Pendall, E
dc.date.accessioned	2024-12-10T23:27:13Z
dc.date.available	2024-12-10T23:27:13Z
dc.date.issued	2024-10-01
dc.identifier.citation	Journal of Geophysical Research: Biogeosciences, 2024, 129, (10)
dc.identifier.issn	2169-8953
dc.identifier.issn	2169-8961
dc.identifier.uri	http://hdl.handle.net/10453/182465
dc.description.abstract	Ecosystem respiration (Reco) arises from interacting autotrophic and heterotrophic processes constrained by distinct drivers. Here, we evaluated up-scaling of observed components of Reco in a mature eucalypt forest in southeast Australia and assessed whether a land surface model adequately represented all the fluxes and their seasonal temperature responses. We measured respiration from soil (Rsoil), heterotrophic soil microbes (Rh), roots (Rroot), and stems (Rstem) in 2018–2019. Reco and its components were simulated using the CABLE–POP (Community Atmosphere-Biosphere Land Exchange–Population Orders Physiology) land surface model, constrained by eddy covariance and chamber measurements and enabled with a newly implemented Dual Arrhenius and Michaelis-Menten (DAMM) module for soil organic matter decomposition. Eddy-covariance based Reco (Reco.eddy, 1,439 g C m−2 y−1) was slightly higher than the sum of the respiration components (Reco.sum, 1,295 g C m−2 y−1) and simulated Reco (1,297 g C m−2 y−1). The largest mean contribution to Reco was from Rsoil (64%) across seasons. The measured contributions of Rh (49%), Rroot (15%), and Rstem (22%) to Reco.sum were very close to model outputs of 46%, 11%, and 22%, respectively. The modeled Rh was highly correlated with measured Rh (R2 = 0.66, RMSE = 0.61), empirically validating the DAMM module. The apparent temperature sensitivities (Q10) of Reco were 2.22 for Reco.sum, 2.15 for Reco.eddy, and 1.57 for CABLE-POP. This research demonstrated that bottom-up respiration component measurements can be successfully scaled to eddy covariance-based Reco and help to better constrain the magnitude of individual respiration components as well as their temperature sensitivities in land surface models.
dc.language	English
dc.publisher	AMER GEOPHYSICAL UNION
dc.relation.ispartof	Journal of Geophysical Research: Biogeosciences
dc.relation.isbasedon	10.1029/2024JG008064
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	0404 Geophysics
dc.subject.classification	3706 Geophysics
dc.title	Reconciling Top-Down and Bottom-Up Estimates of Ecosystem Respiration in a Mature Eucalypt Forest
dc.type	Journal Article
utslib.citation.volume	129
utslib.for	0404 Geophysics
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Science
pubs.organisational-group	University of Technology Sydney/Faculty of Science/School of Life Sciences
utslib.copyright.status	open_access	*
dc.rights.license	This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-nd/4.0/
dc.date.updated	2024-12-10T23:27:10Z
pubs.issue	10
pubs.publication-status	Published
pubs.volume	129
utslib.citation.issue	10

Abstract:

Ecosystem respiration (Reco) arises from interacting autotrophic and heterotrophic processes constrained by distinct drivers. Here, we evaluated up-scaling of observed components of Reco in a mature eucalypt forest in southeast Australia and assessed whether a land surface model adequately represented all the fluxes and their seasonal temperature responses. We measured respiration from soil (Rsoil), heterotrophic soil microbes (Rh), roots (Rroot), and stems (Rstem) in 2018–2019. Reco and its components were simulated using the CABLE–POP (Community Atmosphere-Biosphere Land Exchange–Population Orders Physiology) land surface model, constrained by eddy covariance and chamber measurements and enabled with a newly implemented Dual Arrhenius and Michaelis-Menten (DAMM) module for soil organic matter decomposition. Eddy-covariance based Reco (Reco.eddy, 1,439 g C m−2 y−1) was slightly higher than the sum of the respiration components (Reco.sum, 1,295 g C m−2 y−1) and simulated Reco (1,297 g C m−2 y−1). The largest mean contribution to Reco was from Rsoil (64%) across seasons. The measured contributions of Rh (49%), Rroot (15%), and Rstem (22%) to Reco.sum were very close to model outputs of 46%, 11%, and 22%, respectively. The modeled Rh was highly correlated with measured Rh (R2 = 0.66, RMSE = 0.61), empirically validating the DAMM module. The apparent temperature sensitivities (Q10) of Reco were 2.22 for Reco.sum, 2.15 for Reco.eddy, and 1.57 for CABLE-POP. This research demonstrated that bottom-up respiration component measurements can be successfully scaled to eddy covariance-based Reco and help to better constrain the magnitude of individual respiration components as well as their temperature sensitivities in land surface models.

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http://hdl.handle.net/10453/182465