Carbon budget at tropical forest in the Amazon region

The CO2 gas has an important role for the climate change issue due to the greenhouse effect. Several experiments have been conducted to estimate the impact of the CO2 exchange between vegetation and the atmosphere. The Jacarex/Macoe Project is a british-brazilian cooperation done during 1995-1996 in a tropical undisturbed forest in the central Amazon (Reserva Biologica Cuieiras, Manaus-AM). The measurements were collected at the top of a micromet tower (45 m height). The CO2 concentration shows values ranging from 363 ppm (at 12 LT) to 418 ppm (7 LT) during the dry season, decreasing these values to a range of 351 ppm (17 LT) to 394 ppm (5 LT) at the wet period. On average the CO2 concentration was higher during the dry season (4.7 %). At nighttime conditions and early morning there is a realease of CO2 from the vegetation to the atmosphere with a maximum turbulent flux of CO2 of +12.9 µmol.m-2.s-1 (8 LT) at the dry season and +11.4 µmol.m-2.s-1 (7 LT) during the wet season. During the daytime there is an uptake of CO2 from the atmosphere with values of -14.5 µmol.m-2.s-1 during the dry season and - 16.4 µmol.m-2.s-1 for the wet conditions. A preliminary carbon budget has shown that the forest is doing a sequestration of -4.97 ton C.ha-1.year-1 for the dry season and increasing this value to -5.84 ton C.ha-1.year-1 during the wet season.