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Quantitative determination of microbial activity and community nutritional status in estuarine sediments: evidence for a disturbance artifactIn estuarine sediments with a high degree of vertical heterogeneity in reduced substrate and terminal electron acceptor concentrations, the method of exposure of the microbiota to labeled substrates can introduce a "disturbance artifact" into measures of metabolic activity. The detection of this artifact is based on quantitative measurement of the relative rates of incorporation of [14C]acetate into phospholipid fatty acids (PLFA) and endogenous storage lipid, poly-beta-hydroxyalkanoate (PHA). Previous studies have shown that PLFA synthesis measures cellular growth and that PHA synthesis measures carbon accumulation (unbalanced growth). The "disturbance artifact" of exposure to [14C]acetate was demonstrated by comparing injection of a core with the usual or pore-water replacement or slurry techniques. Only injection of labeled substrate allowed detection of preassay disturbance of the sediment with a garden rake. The raking increased PLFA synthesis with little effect to differences in concentration or distribution of [14C]acetate in the 10-min incubation. Bioturbation induced by sand dollar feeding in estuarine sediment could be detected in an increased PLFA/PHA ratio which was due to decreased PHA synthesis if the addition of labeled substrate was by the injection technique. Addition of labeled precursors to sediment by slurry or pore-water replacement induces greater disturbance artifacts than injection techniques.
Document ID
20040121474
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Findlay, R. H.
(Florida State University Tallahassee 32306, United States)
Pollard, P. C.
Moriarty, D. J.
White, D. C.
Date Acquired
August 22, 2013
Publication Date
January 1, 1985
Publication Information
Publication: Canadian journal of microbiology
Volume: 31
ISSN: 0008-4166
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG2-149
CONTRACT_GRANT: OCE-80-19757
CONTRACT_GRANT: N001482-0404
Distribution Limits
Public
Copyright
Other

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