TY - JOUR
T1 - Modeling and measuring biogeochemical reactions
T2 - System consistency, data needs, and rate formulations
AU - Yeh, Gour Tsyh
AU - Burgos, William D.
AU - Zachara, John M.
N1 - Funding Information:
This research was partially supported by National Science Foundation (NSF) Grant No. EAR-9708494, and by the Natural and Accelerated Bioremediation Research Program (NABIR), Office of Biological and Environmental Research (OBER), US Department of Energy (DOE) Grant No. DE-FG02-98ER62691, both with the Pennsylvania State University. The continued support of Dr Anna Palmisano at DOE is appreciated. We thank Dr Brian Dempsey and Dr Chris Duffy for their review and discussion of the manuscript, and Dr Jim Kubicki for generation of the molecular model used in Fig. 1 .
PY - 2001/8
Y1 - 2001/8
N2 - This paper intends to lay-out a foundation of protocols for planning and analyzing biogeochemical experiments. It presents critical theoretical issues that must be considered for proper application of reaction-based biogeochemical models. The selection of chemical components is not unique and a decomposition of the reaction matrix should be used for formal selection. The decomposition reduces the set of ordinary differential equations governing the production-consumption of chemical species into three subsets of equations: mass action; kinetic-variable; and mass conservation. The consistency of mass conservation equations must be assessed with experimental data before kinetic modeling is initiated. Assumptions regarding equilibrium reactions should also be assessed. For a system with M chemical species involved in N reactions with NI linearly-independent reactions and NE linearly-independent equilibrium reactions, the minimum number of chemical species concentration vs. time curves that must be measured to evaluate the kinetic suite of reactions using a reaction-based model will be (NI-NE). However, for a partial assessment of system consistency, at least one more species must be measured [i.e. (NI-NE+1)]. For a complete assessment of system consistency, (NI-NE+NC) additional species would have to be measured, where NC is the number of chemical components. Reaction rates for kinetic reactions that are linearly independent of other kinetic reactions can be determined based on only one profile of a kinetic-variable concentration vs. time for each kinetic reaction. Reaction rates for parallel kinetic reactions that are linearly dependent on each other cannot be uniquely segregated when they result in production of the same species, however, they must be included for simulation purposes. Kinetic reactions that are linearly dependent only on equilibrium reactions are redundant and do not have to be modeled. The bioreduction of ferric oxide is used as an example to functionally demonstrate these points, and shows that Henri-Michaelis-Benton-Monod kinetics should be applied with care to coupled abiotic and biotic systems.
AB - This paper intends to lay-out a foundation of protocols for planning and analyzing biogeochemical experiments. It presents critical theoretical issues that must be considered for proper application of reaction-based biogeochemical models. The selection of chemical components is not unique and a decomposition of the reaction matrix should be used for formal selection. The decomposition reduces the set of ordinary differential equations governing the production-consumption of chemical species into three subsets of equations: mass action; kinetic-variable; and mass conservation. The consistency of mass conservation equations must be assessed with experimental data before kinetic modeling is initiated. Assumptions regarding equilibrium reactions should also be assessed. For a system with M chemical species involved in N reactions with NI linearly-independent reactions and NE linearly-independent equilibrium reactions, the minimum number of chemical species concentration vs. time curves that must be measured to evaluate the kinetic suite of reactions using a reaction-based model will be (NI-NE). However, for a partial assessment of system consistency, at least one more species must be measured [i.e. (NI-NE+1)]. For a complete assessment of system consistency, (NI-NE+NC) additional species would have to be measured, where NC is the number of chemical components. Reaction rates for kinetic reactions that are linearly independent of other kinetic reactions can be determined based on only one profile of a kinetic-variable concentration vs. time for each kinetic reaction. Reaction rates for parallel kinetic reactions that are linearly dependent on each other cannot be uniquely segregated when they result in production of the same species, however, they must be included for simulation purposes. Kinetic reactions that are linearly dependent only on equilibrium reactions are redundant and do not have to be modeled. The bioreduction of ferric oxide is used as an example to functionally demonstrate these points, and shows that Henri-Michaelis-Benton-Monod kinetics should be applied with care to coupled abiotic and biotic systems.
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U2 - 10.1016/S1093-0191(00)00057-5
DO - 10.1016/S1093-0191(00)00057-5
M3 - Article
AN - SCOPUS:0009028490
SN - 1093-0191
VL - 5
SP - 219
EP - 237
JO - Advances in Environmental Research
JF - Advances in Environmental Research
IS - 3
ER -