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Diurnal and seasonal variation of carbon dioxide exchange from a former true raised bog
Author(s) -
NIEVEEN JOOST P.,
JACOBS COR. M. J.,
JACOBS ADRIE F. G.
Publication year - 1998
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1998.00189.x
Subject(s) - eddy covariance , peat , environmental science , carbon dioxide , bog , growing season , atmospheric sciences , soil respiration , zoology , ecosystem respiration , ecosystem , agronomy , soil water , ecology , soil science , biology , geology
Carbon dioxide exchange was measured, using the eddy covariance technique, during a one and a half year period in 1994 and 1995. The measurements took place over a former true raised bog, characterized by a shallow peat layer and a vegetation dominated by Molinia caerulea . The growing season extended from May until late October, with a maximum LAI in August of 1.7. The carbon balance shows a net release of 97 g C m –2 y –1 (265 kg C ha –1 y –1 ) from the peat bog ecosystem to the atmosphere. During June, July and August there is net consumption of CO 2 , while during the rest of the year there is net production of CO 2 . The average daytime assimilation rates ranged between – 0.2 and – 0.5 mg CO 2 m –2 s –1 (– 45 and –11.3 μmol CO 2 m –2 s –1 ), in a period where the LAI ranged between 1 and 1.7. A high vapour pressure deficit (> 15 hPa) corresponding with high temperatures was found to reduce the assimilation rate by on average 50%. Apart from these factors, LAI and the soil temperature codetermine the net exchange of CO 2 . The total nocturnal respiration during the growing season lies within the same order as the average daytime net assimilation rate. Temperature was found to be the main factor controlling soil respiration, with a Q 10 of 4.8.