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Detailed Reference Information |
Doughty, C.E., Goulden, M.L., Miller, S.D. and da Rocha, H.R. (2006). Circadian rhythms constrain leaf and canopy gas exchange in an Amazonian forest. Geophysical Research Letters 33: doi: 10.1029/2006GL026750. issn: 0094-8276. |
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We used a controlled-environment leaf gas-exchange system and the micrometeorological technique eddy covariance to determine whether circadian rhythms constrain the rates of leaf and canopy gas exchange in an Amazonian forest over a day. When exposed to continuous and constant light for 20 to 48 hours leaves of eleven of seventeen species reduced their photosynthetic rates and closed their stomata during the normally dark period and resumed active gas exchange during the normally light period. Similarly, the rate of whole-forest CO2 uptake at a predetermined irradiance declined during the late afternoon and early morning and increased during the middle of the day. We attribute these cycles to circadian rhythms that are analogous to ones that have been reported for herbaceous plants in the laboratory. The importance of endogenous gas exchange rhythms presents a previously unrecognized challenge for efforts to both interpret and model land-atmosphere energy and mass exchange. |
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Abstract |
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Keywords
Biogeosciences, Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912), Biogeosciences, Biogeophysics, Biogeosciences, Diel, seasonal, and annual cycles, Biogeosciences, Plant ecology, Global Change, Land/atmosphere interactions (1218, 1843, 3322) |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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