1. Continuous Measurements of Fluxes of Biogenic VOCs in the Amazon Basin L.V. Gatti 1, C. R. Trostdorf 1, A. M. Cordova 1, A. Yamazaki 1, C.A.B.Aquino 2, N. Bonelli 2, W. C. Martins 3, A. Guenther 4 1 - Instituto de Pesquisas Energéticas e Nucleares (IPEN), Travessa R, 400, Cidade Universitária, São Paulo, Brazil, CEP: 05508-900. lvgatti@net.ipen.br 2 - ULBRA Instituto Luterano de Ensino Superior de Ji-Parana, Brazil 3 - Universidade Federal do Para, Santarem, Brazil 4 - NCAR – Atmospheric Chemistry Division, Boulder, CO, USA Laboratório de Química Atmosférica Figure 7 - Fazenda Nossa Sra Ouro Preto do Oeste - Rondônia samples to 3m and 8m height Figure 5 - Reserva Biológica do Jarú - Rondônia samples to 56 m and 66 m height Figure 6 - Satelate Image of Rondonia State INTRODUCTION It is well recognized that the tropical forests are an important global source of VOC (volatile organic compounds), as well as a number of other atmospheric trace gases. The high biodiversity in tropical rainforests complicates the extrapolation of biogenic volatile organic compound (BVOC) emissions from leaf-level measurements to landscape and regional or global scales. In Amazonia, a significant fraction of the carbon emitted from the biosphere to the atmosphere is emitted in the form of VOCs, and the knowledge of these fluxes is important to our understanding of the tropical and global atmospheric chemistry and carbon cycling. As part of the LBA (The Large Scale Biosphere-Atmosphere Experiment in Amazonian) experiment, continuous VOCs gradient measurements are being performed in four sites in Amazonia. The first two sites are located at the National Forest of Tapajós, Pará State, Santarém, Km 67 of BR 163, one at a primary forest (Figure 1), and other at a forest were selective logging is taking place, Km 83 of BR 163 (Figure 3 and 4). The other two sites are located in the Rondonia state, at a primary forest and also at a pasture site (Figure 5 and 6 respectively). Figure 1- National Forest of Tapajós, Pará State, Santarém, Km 67 of BR 163 Figure 2- National Forest of Tapajós, Pará State Figure 3- National Forest of Tapajós, Pará State, Santarém, Km 83 of BR 163 Figure 4- National Forest of Tapajós, Pará State, Santarém, Km 83 of BR 163 RESULTS The average isoprene flux in Santarem is around 2 mg m -2 h -1, with an average concentration of about 2 ppb in the Km 67 site. For the selective logging forest, at the Km 83, the average flux is about 1 mg m -2 h -1, with an average concentration ~ 2 ppb. The measurements were made at 65 and 55 m heights simultaneously in an LBA Tower (25 and 15 meters above forest canopy, respectively – Figure 8). The forest site in Rondonia is the Biological Reserve of Jaru, a primary forest. The flux obtained at Rondonia is about 3 mg m -2 h -1. The gradient measurements are taking place at 65 and 55 m above the ground (30 and 20 m above forest canopy, respectively). The average isoprene concentration is about 5 ppb. In the pasture site (grassland site), the gradient measurements are taking place at 8 and 3 m above the ground and the flux results for the pasture site is around 0.5 mg m -2 h -1. The average isoprene concentration at the pasture is ~1.7 ppb. The expected seasonality of VOC fluxes and emissions are being captured. Figure 8 – Canister collecting system CONCLUSIONS The preliminary results indicates that the perturbed forest respond with smaller isoprene emission. Isoprene fluxes at the pasture site are around 4 times smaller than primary forest. With extensive land use change in Amazonia, significant lower isoprene concentrations will be observed. Finantial suport Finantial suport FAPESP- Fundação de Amparo à Pesquisa do Estado de São Paulo and CNPq - MilenioLBA Figure 11 - Fazenda Nossa Sra Ouro Preto do Oeste - Rondônia samples to 3m and 8m height Figure 12 – Fluxes gradiente measurements in pasture site at Rondônia Figure 9 - Reserva Biológica do Jarú - Rondônia samples to 56 m and 66 m height Figure 10 - Fluxes Gradiente measurements in Rebio Jarú - samples to 56 m and 66 m height Figure 13- National Forest of Tapajós, Pará State, Santarém, Km 67 of BR 163 samples in 64 and 54 m Figure 14- Fluxes Gradiente measurements in National Forest of Tapajós, Pará State, Santarém, Km 67 of BR 163 samples in 64 and 54 m Figure 15 - National Forest of Tapajós, Pará State, Santarém, Km 83 of BR 163 samples in 64 and 54 m Figure 16 - Fluxes Gradiente measurements in National Forest of Tapajós, Pará State, Santarém, Km 83 of BR 163 samples in 64 and 54 m