Fluxes of CO2 above a plantation of Eucalyptus in southeast Brazil

Autor(es)

Cabral, Osvaldo M. R. ^[1] ; Gash, John H. C. ^{[2, 3]} ; Rocha, Humberto R. ^[4] ; Marsden, Claire ^[5] ; Ligo, Marcos A. V. ^[1] ; Freitas, Helber C. ^[4] ; Tatsch, Jonatan D. ^[4] ; Gomes, Eduardo ^[4]

Afiliação do(s) autor(es)

^[1] Embrapa Meio Ambiente, BR-13820000 Jaguariuna, SP - Brazil

^[2] Ctr Ecol & Hydrol, Wallingford OX10 8BB, Oxon - England

^[3] Vrije Univ Amsterdam, NL-1081 HV Amsterdam - Netherlands

^[4] Univ Sao Paulo, BR-05508090 Sao Paulo - Brazil

^[5] CIRAD, UPR80, UMR Eco&Sols, Montpellier - France

• Tipo de documento: Artigo Científico
• Fonte: Agricultural and Forest Meteorology; v. 151, n. 1, p. 49-59, JAN 15 2011.
• Citações Web of Science: 14

Resumo

Eddy-covariance measurements of net ecosystem exchange of CO(2) (NEE) and estimates of gross ecosystem productivity (GEP) and ecosystem respiration (R(E)) were obtained in a 2-4 year old Eucalyptus plantation during two years with very different winter rainfall In the first (drier) year the annual NEE GEP and RE were lower than the sums in the second (normal) year and conversely the total respiratory costs of assimilated carbon were higher in the dry year than in the normal year Although the net primary production (NPP) in the first year was 23% lower than that of the second year the decrease in the carbon use efficiency (CUE = NPP/GEP) was 11% and autotrophic respiration utilized more resources in the first dry year than in the second normal year The time variations in NEE were followed by NPP because in these young Eucalyptus plantations NEE is very largely dominated by NPP and heterotrophic respiration plays only a relatively minor role During the dry season a pronounced hysteresis was observed in the relationship between NEE and photosynthetically active radiation and NEE fluxes were inversely proportional to humidity saturation deficit values greater than 0 8 kPa Nighttime fluxes of CO(2) during calm conditions when the friction velocity (u) was below the threshold (0 25 ms(-1)) were estimated based on a Q(10) temperature-dependence relationship adjusted separately for different classes of soil moisture content which regulated the temperature sensitivity of ecosystem respiration (C) 2010 Elsevier B V All rights reserved (AU)

• Processo FAPESP: 08/58120-3 - Carbon tracker and water availability controls of land use and climate changes
• Beneficiário: Humberto Ribeiro da Rocha
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático