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Contribution of transpiration to forest ambient vapour based on isotopic measurements
Author(s) -
MOREIRA MARCELO,
STERNBERG LEONEL,
MARTINELLI LUIZ,
VICTORIA REYNALDO,
BARBOSA EDELCILIO,
BONATES LUIZ,
NEPSTAD DANIEL
Publication year - 1997
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1997.00082.x
Subject(s) - transpiration , environmental science , amazon rainforest , rainforest , atmospheric sciences , deforestation (computer science) , evaporation , hydrology (agriculture) , canopy , dry season , water vapor , water content , tropical rainforest , ecology , geography , geology , botany , biology , meteorology , photosynthesis , geotechnical engineering , computer science , programming language
Using a simple isotope mixing model, we evaluated the relative proportion of water vapour generated by plant transpiration and by soil evaporation at two sites in the Amazon basin. Sampling was carried out at two different soil covers (forest and pasture), in a seasonal tropical rainforest at eastern Amazon where major deforestation is the result of land‐use change, and compared to a less seasonal central Amazon forest. In both forests, vapour from transpiration was responsible for most, if not all, of the water vapour generated in the forest, while it could not be detected above the grassy pastures. Thus the canopy transpiration may be a major source of water vapour to the forest and perhaps to the atmosphere during the dry season. The results are discussed in relation to predictive models based on net radiation that usually are not able to distinguish between transpiration and evaporation.