Fluxes of isoprene and monoterpenes emitted by Tapajos National Forest, eastern central Amazonian rainforest, Santarem-PA, Brazil

Tuesday, 16 December 2014
Sarah Suely Alves Batalha1, Eliane Gomes Alves2, Jeong-Hoo Park3, Roger Seco4, Julio Tota5, Raoni aquino silva de Santana6, Alex B Guenther7, Saewung Kim8, James N Smith9 and Rodrigo Augusto Ferreira de Souza5, (1)Federal University of West Para, Society, Nature and Development, Santarem, PA, Brazil, (2)INPA National Institute of Amazonian Research, Climate and Environment Department, Manaus, Brazil, (3)National Center for Atmospheric Research, Boulder, CO, United States, (4)University of California Irvine, Department of Earth System Science, Irvine, CA, United States, (5)UEA / INPA / SUNY, Manaus, Brazil, (6)National Institute for Amazon Research (INPA), manaus, Brazil, (7)Pacific Northwest National Laboratory (PNNL), Atmospheric Sciences and Global Change Division, Richland, WA, United States, (8)University of California Irvine, Irvine, CA, United States, (9)NCAR, Boulder, CO, United States
Biogenic Volatile Organic Compounds (BVOCs) play an important role in atmospheric chemistry and biogeochemical cycles. It is known that tropical forests are the biggest source of the dominant BVOCs (i.e. isoprene and monoterpenes) emitted to the atmosphere. Nevertheless, Amazonian rainforest, the world’s largest tropical rainforest, has been poorly explored for isoprene and monoterpene emissions. Recently (June and July 2014), we deployed a PTR-TOF-MS (Proton Transfer Reaction – Time of Flight – Mass Spectrometer) to quantify isoprene and monoterpene emissions using the eddy covariance flux method at the FLONA Tapajos (Floresta Nacional do Tapajos; Tapajos National Forest) in the eastern central Amazon rainforest, Santarem-PA, Brazil. The sample inlet and a 3D-sonic anemometer were located above the forest canopy (~65m), and the air was sampled through a long Teflon tube (100m) with high flow rate (40L/min) to the PTR-TOF-MS. From preliminary results for the first 3 days, concentrations and fluxes of m/z 69 (isoprene; C5H8-H+) and m/z 137 (total monoterpenes; C10H16-H+) showed a clear circadian cycle (high during daytime and low at nighttime), suggesting the emissions of these compounds are light and temperature dependent. Our study provides the first PTR-TOF-MS flux observations of isoprene and total monoterpenes at the Flona Tapajos. Moreover, since there are variations on the emissions, when comparing different environments of the huge Amazon basin, these results from eastern central Amazonia will contribute to improving regional and global BVOC emission model estimates.