Photosynthesis and sup 13 C/ sup 12 C ratios in Amazonian rain forests

Journal Article · Mon May 01 00:00:00 EDT 1989 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(89)90213-5· OSTI ID:5020446

Van Der Merwe, N J ^[1]; Medina, E ^[2]

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1. Univ. of Cape Town, Rondebosch (South Africa)
2. Instituto Venezolano de Investigaciones Cientificas, Caracas (Venezuela)

Measurements are reported of {sup 13}C/{sup 12}C ratios for air CO{sub 2} at different heights in two Amazonian rain forests. CO{sub 2} emitted from the forest floor is severely depleted in {sup 13}C which produces isotopically light source air throughout the forest. Air {delta}{sup 13}C values vary very little with height above ground, but are about 5 to 6{per thousand} more negative than the open atmosphere. CO{sub 2} recycling under the canopy depletes all leaf {delta}{sup 13}C values by a like amount. Additional factors further deplete leaf {delta}{sup 13}C values by 4 to 5{per thousand} at ground level; this effect decreases with height to zero in the upper canopy, yielding a gradient in {delta}{sup 13}C values.

• OSTI ID: 5020446
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 53:5; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
54 ENVIRONMENTAL SCIENCES
BRAZIL
ATMOSPHERIC CHEMISTRY
SOILS
CARBON DIOXIDE
ISOTOPE RATIO
AMAZON RIVER
CARBON 12
CARBON 13
PHOTOSYNTHESIS
RESPIRATION
SOIL CHEMISTRY
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DEVELOPING COUNTRIES
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
ISOTOPES
LATIN AMERICA
LIGHT NUCLEI
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RIVERS
SOUTH AMERICA
STABLE ISOTOPES
STREAMS
SURFACE WATERS
SYNTHESIS
580000* - Geosciences
540120 - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)