PARENT SESSION
Oral Session #62: Forest Carbon Dynamics.
Presiding: R. Norby
Wednesday, August 7. 1:00 PM to 4:45 PM. Greenlee Meeting Room, TCC.
Effect of labile carbon additions on N2O emissions from forest soils in southwestern Brazilian Amazon.
GARCIA-MONTIEL, Diana*,1, MELILLO, JERRY1, STEUDLER, PAUL1, NEILL, CHRISTOPHER1, CERRI, CARLOS2, FEIGL, BRIGETTE2, PICCOLO, MARISA2, 1 The Ecosystems Center, MBL, Woods Hole, MA, US2 The Ecosystems Center, MBL, Woods Hole, MA, US
ABSTRACT- The availability of labile organic carbon for microbial metabolic processes could be an important factor regulating N2O emissions from tropical soils. We investigated how an increase in labile C affects N2O and CO2 emissions from forest soils in the southwestern Brazilian Amazon State of Rondonia. Experimental manipulations included the addition of NO3- or glucose to field plots in the forest and of NH4+, NO3- and/or glucose to laboratory incubations of soils. The addition of labile carbon dramatically increased the emissions N2O and CO2 from the forest soils. These results indicate a strong C limitation of forest N2O production. In this study and related field observations, we have observed a positive linear correlation between the emissions of N2O and CO2 from forest soils in Rondonia. We have used this relationship together with our process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM), to predict N2O emissions for the Amazon Basin. For the period 1980-1995, we estimate annual basin-wide N2O-N emissions of between 0.74 and 0.83 Tg.
KEY WORDS: AMAZON, NITROUS OXIDE, SOIL RESPIRATION, CARBON DIOXIDE