title: Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses.
abstract: The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.3 (confidence interval: 0.0 to 2.0) megagrams of carbon per hectare per year. Biometric observations confirmed the net loss but imply that it is a transient effect of recent disturbance superimposed on long-term balance. Given that episodic disturbances are characteristic of old-growth forests, it is likely that carbon sequestration is lower than has been inferred from recent eddy covariance studies at undisturbed sites.
authors.affiliation: Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA. saleska@fas.harvard.edu
authors.forename: Scott R
authors.initials: SR
authors.lastname: Saleska
authors.forename: Scott D
authors.initials: SD
authors.lastname: Miller
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Matross
authors.forename: Michael L
authors.initials: ML
authors.lastname: Goulden
authors.forename: Steven C
authors.initials: SC
authors.lastname: Wofsy
authors.forename: Humberto R
authors.initials: HR
authors.lastname: da Rocha
authors.forename: Plinio B
authors.initials: PB
authors.lastname: de Camargo
authors.forename: Patrick
authors.initials: P
authors.lastname: Crill
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Daube
authors.forename: Helber C
authors.initials: HC
authors.lastname: de Freitas
authors.forename: Lucy
authors.initials: L
authors.lastname: Hutyra
authors.forename: Michael
authors.initials: M
authors.lastname: Keller
authors.forename: Volker
authors.initials: V
authors.lastname: Kirchhoff
authors.forename: Mary
authors.initials: M
authors.lastname: Menton
authors.forename: J William
authors.initials: JW
authors.lastname: Munger
authors.forename: Elizabeth Hammond
authors.initials: EH
authors.lastname: Pyle
authors.forename: Amy H
authors.initials: AH
authors.lastname: Rice
authors.forename: Hudson
authors.initials: H
authors.lastname: Silva
mesh_terms: D001938:Brazil; D002244:Carbon / Q000032:analysis* / Q000378:metabolism; D002245:Carbon Dioxide / Q000032:analysis* / Q000378:metabolism; D016001:Confidence Intervals; D017753:Ecosystem; D010101:Oxygen Consumption; D010788:Photosynthesis; D011891:Rain; D012621:Seasons; D014197:Trees / Q000254:growth & development / Q000378:metabolism; D014934:Wood
chemical_list: D002245:Carbon Dioxide; D002244:Carbon