Carbon in Amazon forests: unexpected seasonal fluxes and disturbance-induced losses.
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.
Saleska
Scott R
SR
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA. saleska@fas.harvard.edu
Miller
Scott D
SD
Matross
Daniel M
DM
Goulden
Michael L
ML
Wofsy
Steven C
SC
da Rocha
Humberto R
HR
de Camargo
Plinio B
PB
Crill
Patrick
P
Daube
Bruce C
BC
de Freitas
Helber C
HC
Hutyra
Lucy
L
Keller
Michael
M
Kirchhoff
Volker
V
Menton
Mary
M
Munger
J William
JW
Pyle
Elizabeth Hammond
EH
Rice
Amy H
AH
Silva
Hudson
H
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
D002245:Carbon Dioxide; D002244:Carbon