Premium
NOCTURNAL ACCUMULATION OF CO 2 UNDERNEATH A TROPICAL FOREST CANOPY ALONG A TOPOGRAPHICAL GRADIENT
Author(s) -
Araújo Alessandro C.,
Kruijt Bart,
Nobre Antonio D.,
Dolman Albertus J.,
Waterloo Maarten J.,
Moors Eddy J.,
Souza Juliana S.
Publication year - 2008
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/06-0982.1
Subject(s) - eddy covariance , environmental science , atmospheric sciences , dry season , canopy , wet season , altitude (triangle) , rainforest , carbon dioxide , diurnal temperature variation , seasonality , terrain , daytime , hydrology (agriculture) , ecosystem , ecology , geology , biology , geometry , mathematics , geotechnical engineering
Flux measurements of carbon dioxide and water vapor above tropical rain forests are often difficult to interpret because the terrain is usually complex. This complexity induces heterogeneity in the surface but also affects lateral movement of carbon dioxide (CO 2 ) not readily detected by the eddy covariance systems. This study describes such variability using measurements of CO 2 along vertical profiles and along a toposequence in a tropical rain forest near Manaus, Brazil. Seasonal and diurnal variation was recorded, with atmospheric CO 2 concentration maxima around dawn, generally higher CO 2 build‐up in the dry season and stronger daytime CO 2 drawdown in the wet season. This variation was reflected all along the toposequence, but the slope and valley bottom accumulated clearly more CO 2 than the plateaus, depending on atmospheric stability. Particularly during stable nights, accumulation was along lines of equal altitude, suggesting that large amounts of CO 2 are stored in the valleys of the landscape. Flushing of this store only occurs during mid‐morning, when stored CO 2 may well be partly transported back to the plateaus. It is clear that, for proper interpretation of tower fluxes in such complex and actively respiring terrain, the horizontal variability of storage needs to be taken into account not only during the night but also during the mornings.