Isotopic composition of respired CO2 and seasonal variability in the Amazon tropical Forest / A composição isotópica do CO2 respirado e sua variabilidade sazonal na Amazônia Oriental

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This study was conducted in 2003 and 2004 at the km 67 old growth forest in the Tapajós National Forest (2 ° 51'S 54 ° 58'W). The objective was measure the carbon isotope ratio (13C/12C) of respired CO2 from the entire ecosystem and isotope composition of organic components leaves, soil, litter and dead wood. The Keeling plot technique and Farquhar's leaf model was used to examine the physiological drivers of the isotopic composition of these components as well as the seasonal response for them. A variation of respired δ13CR - CO2 by the ecosystem was well related with precipitation variation, VPD and PAR, and a significant seasonal difference was found in 2003. The δ13C of leaf organic matter showed a clear stratification along the vertical profile. The estimated ci/ca ratio values showed significant differences between heights and seasons. The results indicated that the isotopic composition of respired CO2 and organic matter was sensitive to microclimatic variations; so far the δ13C values can be used to understand how environmental changes can affect the carbon cycle at ecosystem scale.

ASSUNTO(S)

eastern amazon florestas tropicais amazônia oriental mudanças climáticas. stable isotopes isótopos estáveis climatic changes tropical forests

ACESSO AO ARTIGO

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