HR: 1340h
AN: B43A-0256 [Abstracts]
TI: Comparison of Two Chamber Methods for Measuring Soil CO2 Fluxes
AU: * McDermitt, D
EM: dmcdermitt@licor.com
AF: LI-COR Biosciences, 4421 Superior Street, Lincoln, NE 68504
United States
AU: Xu, L
EM: lxu@licor.com
AF: LI-COR Biosciences, 4421 Superior Street, Lincoln, NE 68504
United States
AU: Welles, J
EM: jwelles@licor.com
AF: LI-COR Biosciences, 4421 Superior Street, Lincoln, NE 68504
United States
AU: Demetriades-shah, T
EM: tdshah@licor.com
AF: LI-COR Biosciences, 4421 Superior Street, Lincoln, NE 68504
United States
AU: Furtaw, M
EM: mfurtaw@licor.com
AF: LI-COR Biosciences, 4421 Superior Street, Lincoln, NE 68504
United States
AB:
Soil CO2 emissions are a large and important component of the global carbon cycle. However chamber soil CO2 flux measurements
are subject to various influences which can lead to misunderstandings and disagreements. The disagreements stem from the
fact that soil is typically porous with a high concentration of CO2 just below the surface so that the slightest disturbances
in the chamber pressure or the chamber to soil CO2 concentration gradient can significantly suppress or enhance the measured
flux. In this presentation we show examples of soil CO2 flux measurement variations caused by chamber design features and
measurement protocols. We discuss differences between a protocol which maintains the chamber CO2 concentration close to the
ambient atmospheric concentration using a CO2 chemical scrubber with a method which does not require any scrubbing but allows
the chamber CO2 concentration to rise above the ambient. We also present an innovative chamber pressure equilibration vent
which minimizes pressure disturbances during windy conditions and discuss some of the reasons why measured soil CO2 fluxes
might be varying between different researchers.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0428 Carbon cycling (4806)
DE: 0486 Soils/pedology (1865)
SC: Biogeosciences [B]
MN: Fall Meeting 2005