Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-18T10:11:56.715Z Has data issue: false hasContentIssue false

Profiles of CO2 concentration and δ13C values in tropical rain forests of the upper Rio Negro Basin, Venezuela

Published online by Cambridge University Press:  10 July 2009

Ernesto Medina
Affiliation:
Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Aptdo. 1827, Caracas, Venezuela
Gustavo Montes
Affiliation:
Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Aptdo. 1827, Caracas, Venezuela
Elvira Cuevas
Affiliation:
Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Aptdo. 1827, Caracas, Venezuela
Zarko Rokzandic
Affiliation:
Centro de Ecologia, Instituto Venezolano de Investigaciones Cientificas, Aptdo. 1827, Caracas, Venezuela

Abstract

Concentration of CO2, above and below the soil surface and δ13C values of plant tissues, soil litter and organic matter were measured in a caatinga forest of the upper Rio Negro basin in southern Venezuela. CO2, concentrations near the forest floor were consistently higher than in the atmosphere. CO2, gradient in the soil was very steep probably because of the poor aeration in this flood-prone forest. δ13C values of plant tissues showed a clear pattern with lower values in the ground herbaceous plants and under-canopy trees. Tree seedlings showed δ13C values similar to the upper-canopy trees indicating their dependence on reserves carried in the seed from the mother tree. Decomposing litter and soil organic matter also showed δ13C values similar to the upper-canopy trees. It is suggested that lower δ13C values of the shade flora result primarily from the assimilation of CO2, depleted in δ13C originating from soil respiration. Probable effects of low light intensity and physiological factors are discussed.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

LITERATURE CITED

Aoki, M., Yabuki, K. & Koyama, H. 1974. Micrometeorology of Pasoh forest. Mimeographed, IBP-Synthesis Meeting, Kuala Lumpur.Google Scholar
Baumgartner, A. 1968. Ecological significance of the vertical energy distribution in plant stands. Pp. 367374 in Eckardt, F. E. (ed.). Functioning of terrestrial ecosystems at the primary production level Nature Resources Research V, Unesco, Paris.Google Scholar
BjÖrkman, O., Ludlow, M. M. & Morrow, P. A. 1972. Photosynthetic performance of two rainforest species in their natural habitat and analysis of their gas exchange. Carnegie Institution Year Book 71:94102.Google Scholar
Blattner, P. & Hulston, J. R. 1978. Proportional variations of geochemical δ13O scales - an inter-laboratory comparison. Geochimica et cosmochimica acta 42:5962.CrossRefGoogle Scholar
Craig, H. 1957. Isotopic standards for carbon and oxygen and correlation factors for mass-spectrometric analysis of carbon dioxide. Geochimica et cosmochimica acta 12:133149.CrossRefGoogle Scholar
Farquhar, G. D., O'Leary, M. H. & Berry, J. A. 1982. On the relationship between carbon dioxide isotope discrimination and the intercellular carbon dioxide concentration in leaves. Australian Journal of Plant Physiology 9:121137.Google Scholar
Freyer, H. D. 1979. Variations in the atmospheric CO2, content Pp. 79100 in Bolin, B., Degens, E. T., Kempe, S. & Ketner, E. (eds). The global carbon cycle. Scope 13. John Wiley & Sons, Chichester.Google Scholar
Griffiths, H. 1984. Ecological distribution of bromeliads in Trinidad and their δ13C values: implications for the use of δ values to indicate carboxylation pathways in plants. Pp. 145174 in Medina, E. (ed.). Physiological ecology of CAM plants. Ediciones IVIC-CIET, Caracas.Google Scholar
Huber, O. 1978. Light compensation point of vascular plants of a tropical cloud forest and an ecological interpretation. Photosynthetica 12:382390.Google Scholar
Kira, T. 1975. Primary production forests. Pp. 540 in Cooper, J. P. (ed.). Photosynthesis and productivity in different environments. International Biological Programme 3. Cambridge University Press, Cambridge.Google Scholar
Klinge, H., Medina, E. & Herrera, R. 1977. Studies on the ecology of the Amazon Caatinga. Acta Cientifica Venezolana 28:270276.Google Scholar
Lemon, E., Allen, L. H. & Muller, L. 1970. Carbon dioxide exchange of a tropical rain forest Part II. BioScience 20:10541059.CrossRefGoogle Scholar
Medina, E. & Minchin, P. 1980. Stratification of δ13C values in Amazonian rain forests. Oecologia 45:377378.CrossRefGoogle ScholarPubMed
Medina, E., Herrera, R., Jordan, C. F. & Klinge, H. 1977. The Amazon project of the Venezuelan Institute of Scientific Research. Nature and Resources 33:46.Google Scholar
Medina, E., Klinge, H., Jordan, C F. & Herrera, R. 1980. Soli respiration in Amazonian rain forests in the Rio Negro basin. Flora 170:240250.CrossRefGoogle Scholar
Odum, H. T., Drewry, G. & Kline, J. R. 1970. Climate at EI Verde, 1963–68. Pp. B347B418 in Odum, H. T. & Pigeon, R. F. (eds). A tropical rain forest. U.S. Atomic Energy Commission, Oak Ridge, Tennessee.Google Scholar
Osmond, C. B., Valaana, N., Haslam, J. M., Uotila, P. & Roksandic, Z. 1981. Comparisons of δ13C values in leaves of aquatic macrophytes from different habitats in Britain and Finland. Oecologia 50:117124.CrossRefGoogle ScholarPubMed
Pearcy, R. W. & Calkin, H. W. 1983. Carbon dioxide exchange of C3 and C4 tree species in the understory of a Hawaiian forest. Oecologia 58:2632.CrossRefGoogle ScholarPubMed
Richards, P. W. 1952. The tropical rain forest: an ecological study. Cambridge University Press, Cambridge.Google Scholar
Schleser, G. H. & Jayasekera, R. 1985. δ13C-variations of leaves in forests as an indication of reassimilated CO2, from the soil. Oecologia 65:536542.CrossRefGoogle Scholar
Troughton, J. H., Card, K. A. & Hendy, C. H. 1973. Photosynthetic pathways and carbon isotope discrimination by plants. Carnegie Year Book 73:768780.Google Scholar
Vogel, G. C. 1978. Recycling of carbon in a forest environment. Oecologia plantarum 13:8994.Google Scholar
Volkoff, B., Matsui, E. & Cerri, C. C. 1982. Discriminãçao isotópica de carbono nos humus de latossolo e podzol da região Amazónica do Brasil. Pp. 147153 in Cerri, C. C., Athié, D. & Sodrzeieski, D. (eds). Anais do Coloquio Regional sobre matéria orgãnica do solo. Centro de Energia Nuclear na Agriculture CENA/USP, Sao Paulo.Google Scholar