Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest

A.C. de Araujo, J.P.H.B. Ometto, A.J. Dolman, B. Kruijt, M.J. Waterloo, J.R. Ehleringer

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

The carbon isotope of a leaf (d13Cleaf) is generally more negative in riparian zones than in areas with low soil moisture content or rainfall input. In Central Amazonia, the small-scale topography is composed of plateaus and valleys, with plateaus generally having a lower soil moisture status than the valley edges in the dry season. Yet in the dry season, the nocturnal accumulation of CO2 is higher in the valleys than on the plateaus. Samples of sunlit leaves and atmospheric air were collected along a topographical gradient in the dry season to test whether the d13Cleaf of sunlit leaves and the carbon isotope ratio of ecosystem respired CO2 (d13CReco) may be more negative in the valley than those on the plateau. The d13Cleaf was significantly more negative in the valley than on the plateau. Factors considered to be driving the observed variability in d13Cleaf were: leaf nitrogen concentration, leaf mass per unit area (LMA), soil moisture availability, more negative carbon isotope ratio of atmospheric CO2 (d13Ca) in the valleys during daytime hours, and leaf discrimination (¿leaf). The observed pattern of d13Cleaf might suggest that water-use efficiency (WUE) is higher on the plateaus than in the valleys. However, there was no full supporting evidence for this because it remains unclear how much of the difference in d13Cleaf was driven by physiology or &delta13Ca. The d13CReco was more negative in the valleys than on the plateaus on some nights, whereas in others it was not. It is likely that lateral drainage of CO2 enriched in 13C from upslope areas might have happened when the nights were less stable. Biotic factors such as soil CO2 efflux (Rsoil) and the responses of plants to environmental variables such as vapor pressure deficit (D) may also play a role. The preferential pooling of CO2 in the low-lying areas of this landscape may confound the interpretation of d13Cleaf and d13CReco.
Original languageEnglish
Pages (from-to)779-795
JournalBiogeosciences
Volume5
Issue number3
DOIs
Publication statusPublished - 2008

Fingerprint

ecosystem respiration
respiration
valleys
carbon dioxide
plateaus
valley
plateau
ecosystem
leaves
dry season
isotopes
carbon isotope ratio
soil moisture
carbon
soil water
biotic factor
riparian zone
riparian areas
Amazonia
vapor pressure

Keywords

  • carbon-isotope discrimination
  • rain-forest
  • tropical forest
  • water availability
  • natural-abundance
  • deciduous forest
  • cycle research
  • use efficiency
  • boreal forest
  • french-guiana

Cite this

de Araujo, A. C., Ometto, J. P. H. B., Dolman, A. J., Kruijt, B., Waterloo, M. J., & Ehleringer, J. R. (2008). Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest. Biogeosciences, 5(3), 779-795. https://doi.org/10.5194/bg-5-779-2008
de Araujo, A.C. ; Ometto, J.P.H.B. ; Dolman, A.J. ; Kruijt, B. ; Waterloo, M.J. ; Ehleringer, J.R. / Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest. In: Biogeosciences. 2008 ; Vol. 5, No. 3. pp. 779-795.
@article{ed527ad487134986979fd5b554f62b4e,
title = "Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest",
abstract = "The carbon isotope of a leaf (d13Cleaf) is generally more negative in riparian zones than in areas with low soil moisture content or rainfall input. In Central Amazonia, the small-scale topography is composed of plateaus and valleys, with plateaus generally having a lower soil moisture status than the valley edges in the dry season. Yet in the dry season, the nocturnal accumulation of CO2 is higher in the valleys than on the plateaus. Samples of sunlit leaves and atmospheric air were collected along a topographical gradient in the dry season to test whether the d13Cleaf of sunlit leaves and the carbon isotope ratio of ecosystem respired CO2 (d13CReco) may be more negative in the valley than those on the plateau. The d13Cleaf was significantly more negative in the valley than on the plateau. Factors considered to be driving the observed variability in d13Cleaf were: leaf nitrogen concentration, leaf mass per unit area (LMA), soil moisture availability, more negative carbon isotope ratio of atmospheric CO2 (d13Ca) in the valleys during daytime hours, and leaf discrimination (¿leaf). The observed pattern of d13Cleaf might suggest that water-use efficiency (WUE) is higher on the plateaus than in the valleys. However, there was no full supporting evidence for this because it remains unclear how much of the difference in d13Cleaf was driven by physiology or &delta13Ca. The d13CReco was more negative in the valleys than on the plateaus on some nights, whereas in others it was not. It is likely that lateral drainage of CO2 enriched in 13C from upslope areas might have happened when the nights were less stable. Biotic factors such as soil CO2 efflux (Rsoil) and the responses of plants to environmental variables such as vapor pressure deficit (D) may also play a role. The preferential pooling of CO2 in the low-lying areas of this landscape may confound the interpretation of d13Cleaf and d13CReco.",
keywords = "carbon-isotope discrimination, rain-forest, tropical forest, water availability, natural-abundance, deciduous forest, cycle research, use efficiency, boreal forest, french-guiana",
author = "{de Araujo}, A.C. and J.P.H.B. Ometto and A.J. Dolman and B. Kruijt and M.J. Waterloo and J.R. Ehleringer",
year = "2008",
doi = "10.5194/bg-5-779-2008",
language = "English",
volume = "5",
pages = "779--795",
journal = "Biogeosciences",
issn = "1726-4170",
publisher = "European Geosciences Union",
number = "3",

}

de Araujo, AC, Ometto, JPHB, Dolman, AJ, Kruijt, B, Waterloo, MJ & Ehleringer, JR 2008, 'Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest', Biogeosciences, vol. 5, no. 3, pp. 779-795. https://doi.org/10.5194/bg-5-779-2008

Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest. / de Araujo, A.C.; Ometto, J.P.H.B.; Dolman, A.J.; Kruijt, B.; Waterloo, M.J.; Ehleringer, J.R.

In: Biogeosciences, Vol. 5, No. 3, 2008, p. 779-795.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Implications of CO2 pooling on d13C of ecosystem respiration and leaves in Amazonian forest

AU - de Araujo, A.C.

AU - Ometto, J.P.H.B.

AU - Dolman, A.J.

AU - Kruijt, B.

AU - Waterloo, M.J.

AU - Ehleringer, J.R.

PY - 2008

Y1 - 2008

N2 - The carbon isotope of a leaf (d13Cleaf) is generally more negative in riparian zones than in areas with low soil moisture content or rainfall input. In Central Amazonia, the small-scale topography is composed of plateaus and valleys, with plateaus generally having a lower soil moisture status than the valley edges in the dry season. Yet in the dry season, the nocturnal accumulation of CO2 is higher in the valleys than on the plateaus. Samples of sunlit leaves and atmospheric air were collected along a topographical gradient in the dry season to test whether the d13Cleaf of sunlit leaves and the carbon isotope ratio of ecosystem respired CO2 (d13CReco) may be more negative in the valley than those on the plateau. The d13Cleaf was significantly more negative in the valley than on the plateau. Factors considered to be driving the observed variability in d13Cleaf were: leaf nitrogen concentration, leaf mass per unit area (LMA), soil moisture availability, more negative carbon isotope ratio of atmospheric CO2 (d13Ca) in the valleys during daytime hours, and leaf discrimination (¿leaf). The observed pattern of d13Cleaf might suggest that water-use efficiency (WUE) is higher on the plateaus than in the valleys. However, there was no full supporting evidence for this because it remains unclear how much of the difference in d13Cleaf was driven by physiology or &delta13Ca. The d13CReco was more negative in the valleys than on the plateaus on some nights, whereas in others it was not. It is likely that lateral drainage of CO2 enriched in 13C from upslope areas might have happened when the nights were less stable. Biotic factors such as soil CO2 efflux (Rsoil) and the responses of plants to environmental variables such as vapor pressure deficit (D) may also play a role. The preferential pooling of CO2 in the low-lying areas of this landscape may confound the interpretation of d13Cleaf and d13CReco.

AB - The carbon isotope of a leaf (d13Cleaf) is generally more negative in riparian zones than in areas with low soil moisture content or rainfall input. In Central Amazonia, the small-scale topography is composed of plateaus and valleys, with plateaus generally having a lower soil moisture status than the valley edges in the dry season. Yet in the dry season, the nocturnal accumulation of CO2 is higher in the valleys than on the plateaus. Samples of sunlit leaves and atmospheric air were collected along a topographical gradient in the dry season to test whether the d13Cleaf of sunlit leaves and the carbon isotope ratio of ecosystem respired CO2 (d13CReco) may be more negative in the valley than those on the plateau. The d13Cleaf was significantly more negative in the valley than on the plateau. Factors considered to be driving the observed variability in d13Cleaf were: leaf nitrogen concentration, leaf mass per unit area (LMA), soil moisture availability, more negative carbon isotope ratio of atmospheric CO2 (d13Ca) in the valleys during daytime hours, and leaf discrimination (¿leaf). The observed pattern of d13Cleaf might suggest that water-use efficiency (WUE) is higher on the plateaus than in the valleys. However, there was no full supporting evidence for this because it remains unclear how much of the difference in d13Cleaf was driven by physiology or &delta13Ca. The d13CReco was more negative in the valleys than on the plateaus on some nights, whereas in others it was not. It is likely that lateral drainage of CO2 enriched in 13C from upslope areas might have happened when the nights were less stable. Biotic factors such as soil CO2 efflux (Rsoil) and the responses of plants to environmental variables such as vapor pressure deficit (D) may also play a role. The preferential pooling of CO2 in the low-lying areas of this landscape may confound the interpretation of d13Cleaf and d13CReco.

KW - carbon-isotope discrimination

KW - rain-forest

KW - tropical forest

KW - water availability

KW - natural-abundance

KW - deciduous forest

KW - cycle research

KW - use efficiency

KW - boreal forest

KW - french-guiana

U2 - 10.5194/bg-5-779-2008

DO - 10.5194/bg-5-779-2008

M3 - Article

VL - 5

SP - 779

EP - 795

JO - Biogeosciences

JF - Biogeosciences

SN - 1726-4170

IS - 3

ER -