000			03756nab a22006617a 4500
001			39649
003			CO-PlCIA
005			20130510170200.0
008			120504t1995 000 0seng d
040			_aCO-PlCIA _cCO-PlCIA
041			_aeng
100			_aLloyd, J. _97299
245			_aA simple calibrated model of Amazon rainforest productivity based on leaf biochemical properties
300			_a18(10):1129-1145
520			_aA simple 'big leaf' ecosystem gas exchange model was developed, using eddy covariance data collected at an undisturbed tropical rainforest in south-western Amazonia (Brazil). The model used mechanistic equations of canopy biochemistry combined with an empirical stomatal model describing responses to light, temperature and humidity. After calibration, the model was driven using hourly data from a weather station at the top of the tower at the measurement site, yielding an estimate of gross primary productivity (annual photosynthesis) in 1992/1993 of about 200 mol C m(-2) year(-1). Although incoming photon flux density emerged as the major control on photosynthesis in this forest, at a given PAR CO2 assimilation rates were higher in the mornings than in the afternoons. This was attributable to stomatal closure in the afternoon in response to increasing canopy-to-air vapour pressure differences. Although most morning gas exchange was clearly limited by the rate of electron transport, afternoon gas exchange was generally observed to be very nearly co-limited by both Rubisco activity (V-max) and electron transport rate. The sensitivity of the model to changes in nitrogen allocation showed that the modelled ratio of V-max to electron transport (J(max)) served nearly to maximize the annual carbon gain, and indeed, would have resulted in almost maximum annual carbon gain at the pre-industrial revolution atmospheric CO2 concentration of 27 Pa. Modelled gross primary productivity (GPP) was somewhat lower at 27 Pa, being about 160 mol C m(-2) year(-1). The model suggests that, in the absence of any negative feedbacks on GPP, future higher concentrations of atmospheric CO2 win continue to increase the GPP of this rainforest, up to about 230 mol C m(-2) year(-1) at 70 Pa
650			_aTropical rain forests _95551
650			_aMathematical models _97285
650			_aBiochemistry _95803
650			_aPhotosynthesis _95535
650			_aStomata _96493
650			_aRubisco _97286
650			_aCanopy _97287
650			_aProductivity _93460
650			_aAmazonia
650			_aBrazil _92487
650			_aBosque tropical húmedo _95556
650			_aModelo matemático _97288
650			_aBioquímica _95804
650			_aFotosíntesis _95540
650			_aEstoma _96495
650			_aRubisco _97289
650			_aCubierta de copas _97290
650			_aProductividad _93466
650			_aAmazonia
650			_aBrasil _92503
653			_aJournal articles
653			_aArtículos en revistas
653			_aElectronic documents
653			_aDocumentos electrónicos
653			_aFisiología y bioquímica de la planta
653			_aMétodos matemáticos y estadisticos
653			_aEcología vegetal
653			_aPlant physiology and biochemistry
653			_aMathematical and statistical methods
653			_aPlant ecology
653			_aJournal article
700			_aGrace, J. _97291
700			_aMiranda, Antônio Carlos _97292
700			_aMeir, P. _97293
700			_aWONG, S.C. _97294
700			_aMiranda, Heloisa S. _97295
700			_aWright, I.R. _97296
700			_aGash, J.H.C. _97297
700			_aMcIntyre, J. _97298
773			_tPlant, Cell and Environment (United Kingdom) _d1995
942			_2lcc _cJA
998			_aCATAL
999			_c62125 _d62125