HAREN, J. van

HUETE, A.

KELLER, M.

OLIVEIRA, R. C.

SALESKA, S.

RCAAP - Repositório Científico de Acesso Aberto de Portugal

Amazon forest tree species composition influences soil fluxes of CO2 and N2O.

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C lose WindowAmazon forest tree species composition influences soil fluxes of CO2 and N2OJoost van Haren, University of Arizona, jvanhare@email.arizona.edu (Presenting) Scott Saleska, University of Arizona, saleska@email.arizona.edu Alfredo Huete, University of Arizona, ahuete@Ag.arizona.edu Michael Keller, USDA Forest Service, michael@kaos.sr.unh.edu Raimundo Cosme Oliveira, Empresa, Brasileira de Pesquisa Agropecuária - EMBRAPA,,cosme@lbasantarem.com.br Carbon dioxide (CO2) and nitrous oxide (N2O) are important greenhouse gases, but themechanisms controlling their emissions from tropical systems are still poorly understood. Forexample, models using soil microclimate variables typically fail to capture large spatial andtemporal variability, especially in N2O. We tested the hypothesis that tree speciescomposition influences trace gas emission, possibly through its effects on local litterchemistry, root chemistry, and root exudation. We established a spatially distributed samplingscheme (across 50 ha in the Tapajós National Forest near Santarém, Brazil) w ith fluxmeasurement points located near a stratified sample of 10 different canopy and emergenttree species. Our initial results indicate that the species identify of individual treessignificantly influenced the magnitude of nearby N2O fluxes, and that soil parameters like bulkdensity, moisture and temperature could not by account for observed flux variability. We alsofound evidence that species-specific leaf hyperspectral reflectance spectra that have beenused to predict leaf nitrogen variations may also be useful in predicting the magnitude of N2Ofluxes observed near different species. These results suggest that information on speciesdistributions may improve estimates of ecosystem scale fluxes of important trace gases, andthat hyperspectral remote sensing techniques may be useful in acquiring the relevantecosystem-scale information to make such estimates.Science Theme:  TG (Trace Gases)Session:  2C: Trace Gases and AerosolsPresentation Type:  OralAbstract ID: 90View presentationC lose Windowconverted by Web2PDFConvert.com

Amazon forest tree species composition influences soil fluxes of CO2 and N2O.

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RCAAP - Repositório Científico de Acesso Aberto de Portugal

Repository Open Access to Scientific Information from Embrapa