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Carbon dioxide budget in a temperature grassland ecosystemEddy correlation measurements of CO2 flux made during May-October 1987 and June-August 1989 were employed, in conjunction with simulated data, to examine the net exchange of CO2 in a temperature grassland ecosystem. Simulated estimates of CO2 uptake were used when flux measurements were not available. These estimates were based on daily intercepted photosynthetically active radiation, air temperature, and extractable soil water. Soil CO2 flux and dark respiration of the aerial part of plants were estimated using the relationships developed by Norman et al. (1992) and Polley et al. (1992) at the study site. The results indicate that the CO2 exchange between this ecosystem and the atmosphere is highly variable. The net ecosystem CO2 exchange reached its peak value (12-18 g/sq m d) during the period when the leaf area index was maximum. Drought, a frequent occurrence in this region, can change this ecosystem from a sink to a source for atmospheric CO2. Comparison with data on dry matter indicated that the aboveground biomass accounted for about 45-70 percent of the net carbon uptake, suggesting the importance of the below ground biomass in estimating net primary productivity in this ecosystem.
Document ID
19920053497
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kim, Joon
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Verma, Shashi B.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Clement, Robert J.
(Nebraska, University Lincoln, United States)
Date Acquired
August 15, 2013
Publication Date
April 20, 1992
Publication Information
Publication: Journal of Geophysical Research
Volume: 97
Issue: D5 A
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
92A36121
Funding Number(s)
CONTRACT_GRANT: NAG5-890
CONTRACT_GRANT: NSF ATM-85-19026
Distribution Limits
Public
Copyright
Other

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