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

THE INFLUENCE OF FLOODING ON THE EXCHANGE OF OXYGENATED VOLATILE ORGANICCOMPOUNDS BETWEEN AMAZONIAN FLOODPLAIN TREE SPECIES AND THE ATMOSPHERES. Rottenberger (1), U. Kuhn (1), A. Wolf (1), G. Schebeske (1),O. de Simone (2),W. Schmidt (2), E. Müller (3), M.T.F. Piedade (4), J. Kesselmeier (1)(1) Max Planck Institute for Chemistry, Biogeochemistry Dept., Mainz, Germany(2) University Oldenburg, FB Biology, Germany(3) Max Planck Institute for Limnology, Tropical Ecology Dept., Plön, Germany(4) Instituto Nacional de Pesquisas da Amazonia, Manaus, Brasilrottenbe@mpch-mainz.mpg.de / Fax: +49-6131-305428Plants are known to emit considerable quantities of volatile organic compounds (VOC) to theatmosphere. Among biogenically emitted VOC the oxygenated hydrocarbons acetaldehyde andethanol play an important role in atmospheric chemistry. They participate in regulating theoxidative capacity of the atmosphere, are involved in the production of peroxyacetylnitrates(PAN) and are precursors for short-chain acids contributing to the acidity of the atmosphere.Biogenic emissions of acetaldehyde and ethanol are known to occur when plants are subjected tostress conditions (air pollution, freezing) and to hypoxic conditions of the root system induced byflooding. The Central Amazon floodplain is one of the largest flooding areas in the world andplants are subjected to waterlogging for periods over several month. Hence, it is a potential largesource for acetaldehyde and ethanol. In a greenhouse experiment we simulated the floodingsituation and monitored the acetaldehyde and ethanol exchange of tropical trees representative ofCentral Amazonian floodplain forests over a 6-day flooding period by an enclosure method.Large differences in emission rates, diurnal pattern and temporal behavior were observedbetween species depending on the duration of flooding. Our results indicate that different leafemission response patterns are linked to specific differences in adaptive physiological andmorphological strategies of the roots to overcome hypoxic conditions induced by waterlogging.