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Title: Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities

Abstract

The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on microbial growth, community composition and system geochemistry. The hypothesis is that a thermodynamic analysis of the energy-yielding growth reactions performed by defined groups of microorganisms can be used to make quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
926157
Report Number(s):
CONF-ERSP2007/1025387
R&D Project: ERSD 1025387; TRN: US200807%%382
Resource Type:
Conference
Resource Relation:
Conference: Annual Environmental Remediation Science Program (ERSP) Principal Investigator Meeting, April 16-19, 2007, Lansdowne, VA
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; BIOGEOCHEMISTRY; MICROORGANISMS; THERMODYNAMICS; MATHEMATICAL MODELS; SUBSTRATES; CATALYTIC EFFECTS; POPULATION DYNAMICS

Citation Formats

Jack Istok, Melora Park, James McKinley, Chongxuan Liu, Lee Krumholz, Anne Spain, Aaron Peacock, and Brett Baldwin. Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities. United States: N. p., 2007. Web.
Jack Istok, Melora Park, James McKinley, Chongxuan Liu, Lee Krumholz, Anne Spain, Aaron Peacock, & Brett Baldwin. Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities. United States.
Jack Istok, Melora Park, James McKinley, Chongxuan Liu, Lee Krumholz, Anne Spain, Aaron Peacock, and Brett Baldwin. Thu . "Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities". United States. doi:. https://www.osti.gov/servlets/purl/926157.
@article{osti_926157,
title = {Thermodynamic network model for predicting effects of substrate addition and other perturbations on subsurface microbial communities},
author = {Jack Istok and Melora Park and James McKinley and Chongxuan Liu and Lee Krumholz and Anne Spain and Aaron Peacock and Brett Baldwin},
abstractNote = {The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on microbial growth, community composition and system geochemistry. The hypothesis is that a thermodynamic analysis of the energy-yielding growth reactions performed by defined groups of microorganisms can be used to make quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Apr 19 00:00:00 EDT 2007},
month = {Thu Apr 19 00:00:00 EDT 2007}
}

Conference:
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  • Microbial biomass and activity in subsurface environments is determined by the concentration and flux of a variety of electron acceptors, electron donors, and other nutrients. Perturbations associated with sampling and laboratory handling, and intentional perturbations such as those induced during bioremediation, result in changes in the structure and physiological status of the microbial community. The objective of the research is to characterize these changes for the purpose of (1) ensuring that microbial measurements approximate the in-situ condition as closely as possible, and (2) documenting the progress of in-situ bioremediation. Manipulative experiments were performed in the laboratory to assess the impactmore » of disturbance, increased moisture, and increased O{sub 2} on vadose-zone sediments. DNA probes and enrichments for microbial functional groups were used to assess microbial response in sediments during bioremediation of a trichloroethylene (TCE)-contaminated zone 30 to 43 m below the surface at the Savannah River Site. Microbial populations able to degrade trichloroethylene (TCE) under methane-, propane-, and ammonia-oxidizing enrichment conditions commonly increased a minimum of 10- to >1,000-fold in sediments sampled following injection of air, methane, nitrous oxide, and triethyl phosphate, compared to sediments sampled following injection of air only. Results obtained with the soluble methane monooxygenase gene probe showed that cultural enrichment methods commonly underestimate methane-oxidizing populations by several orders of magnitude.« less
  • Previously published research from in situ field experiments at the NABIR Field Research Center have shown that cooperative metabolism of denitrifiers and Fe(III)/sulfate reducers is essential for creating subsurface conditions favorable for U(VI) and Tc(VII) bioreduction (Istok et al., 2004). The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on the composition and functional stability of subsurface microbial communities. The overall scientific hypothesis is that a thermodynamic analysis of the energy-yielding reactions performed by broadly defined groups of microorganisms can be used to makemore » quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change. An interactive computer program was developed to calculate the overall growth equation and free energy yield for microorganisms that grow by coupling selected combinations of electron acceptor and electron donor half-reactions. Each group performs a specific function (e.g. oxidation of acetate coupled to reduction of nitrate); collectively the groups provide a theoretical description of the entire natural microbial community. The microbial growth data are combined with an existing thermodynamic data base for associated geochemical reactions and used to simulate the coupled microbial-geochemical response of a complex natural system to substrate addition or any other environmental perturbations.« less
  • The project is a collaborative task with a larger project headed by Jack Istok at Oregon State University, which is conducted under the same title. The project was conceptualized as follows. A ''geochemical'' model of microbial communities was hypothesized, in which microbes were characterized as mineral species according to the chemical transformations they used for metabolic function. The iron-reducing bacteria, for example, would be represented by the iron reducing chemical reaction, including a specific electron donor, the fraction of the consumed donor used for biomass maintenance or growth, and a free energy for the reaction. The pseudomineral species would thenmore » be included in a standard geochemical model, and community succession could be calculated according to the thermodynamically favored microbially mediated reactions under progressive consumption of electron donors and receptors, and evolving geochemical conditions. The project includes relatively minor participation by the University of Oklahoma and Pacific Northwest National Laboratory, with the major component at OSU. The PNNL project was funded to provide assistance to Dr. Istok in formulating the appropriate modeling approach and geochemical constraints on the modeling effort.« less
  • Short communication.