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|Variações Sazonais De Fluxo E Concentração De Dióxido De Carbono Sobre Uma Área De Floresta Na Região Central Da Amazônia|
Autoria: Rafael Ferreira da Costa
Coautoria: Sylvia Elaine Marques de Farias
Abstract: The measurements of CO2 have been collected during the period of Feb 15-22, 1996 (total rainfall of 109.8 mm) and in Oct 21-28, 1995 (rainfall of 12.6 mm) in central Amazonia, in order to characterize the behavior of the CO2 exchange for wet and dry conditions. During the dry season the maximum CO2 concentration was 418 ppm at 7:00 Local Time (LT), with a minimum of 363 ppm at 12:00 LT. For the wet season, maximum CO2 concentration was 394 ppm at 5:00 Local Time (LT), with a minimum of 351 ppm at 17:00 LT. On average the CO2 concentrations are higher during the dry season (4,7 %). During the nighttime conditions and until early morning, the CO2 fluxes are from the forest to the atmosphere. During the dry season, there was a maximum of +7,2 mmol m-2s-1 at 8:00 LT, while at the wet season this maximum was +9,9 mmol m-2s-1 at 7:00 LT. The flux changes sign (from positive values during the night to negative values during daytime), according to the uptake of CO2 for photosynthesis. During the dry season, the minimum flux was -13,5 mmol m-2s-1 at 11:00 LT, decreasing this value to - 14,5 mmol m-2s-1 at 12 LT for the wet season. The carbon (C) budget for the forest shows that there is a sequestration of -3,98 ton C ha-1 year-1 from the dry season, increasing this number to 4,26 ton C ha-1 year-1 for the wet season.