A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Variations in Isoprene Emission Capacity among Neotropical Forest SitesPeter Harley 1 , Pérola Vasconcellos 2 , Lee Vierling 4 , Alex Guenther 1 , Jim Greenberg 1 ,3 Carlos Cleomir de S. Pinheiro, Lee Klinger1 Atmospheric Chemistry Division, NCAR, 1850 Table Mesa Drive, Boulder CO, USA, harley@ucar.edu2 IPEN, Departamento de Química e Meio Ambiente, São Paulo, SP, Brazil3 INPA –Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil4 South Dakota School of Mines and Technology, Rapid City, SD, USAIsoprene (C 5 H 8 ) is a hydrocarbon produced and emitted by leaves of many tree species, andis the most important volatile organic compound in most rural atmospheres. It is animportant participant in tropospheric chemistry, and carbon losses in the form of isopreneare a small but significant component of the carbon budget in some forest ecosystems.Isoprene emission capacity of sun leaves, defined as the emission rate of isoprene measuredat 30 o C under photosynthetically active radiation of 1000 µmol m -2 s -1 , varies acrossspecies by three orders of magnitude. Approximately 2/3 of those tree species examinedappear to emit very little isoprene (