Document Detail

Dynamics of a pasture soil microbial community after deposition of cattle urine amended with [13C]urea.
MedLine Citation:
PMID:  15528493     Owner:  NLM     Status:  MEDLINE    
Within grazed pastures, urine patches are hot spots of nitrogen turnover, since dietary N surpluses are excreted mainly as urea in the urine. This short-term experiment investigated 13C uptake in microbial lipids after simulated deposition of cattle urine at 10.0 and 17.1 g of urea C m(-2). Confined field plots without or with cattle urine amendment were sampled after 4 and 14 days, and soil from 0- to 5-cm and 10- to 20-cm depths was analyzed for content and composition of phospholipid fatty acids (PLFAs) and for the distribution of urea-derived 13C among individual PLFAs. Carbon dioxide emissions were quantified, and the contributions derived from urea were assessed. Initial changes in PLFA composition were greater at the lower level of urea, as revealed by a principal-component analysis. At the higher urea level, osmotic stress was indicated by the dynamics of cyclopropane fatty acids and branched-chain fatty acids. Incorporation of 13C from [13C]urea was low but significant, and the largest amounts of urea-derived C were found in common fatty acids (i.e., 16:0, 16:1omega7c, and 18:1omega7) that would be consistent with growth of typical NH4(+)-oxidizing (Nitrosomonas) and NO2(-)-oxidizing (Nitrobacter) bacteria. Surprisingly, a 20 per thousand depletion of 13C in the cyclopropane fatty acid cy17:0 was observed after 4 days, which was replaced by a 10 to 20 per thousand depletion of that in cy19:0 after 14 days. Possible reasons for this pattern are discussed. Autotrophic nitrifiers could not be implicated in urea hydrolysis to any large extent, but PLFA dynamics and the incorporation of urea-derived 13C in PLFAs indicated a response of nitrifiers which differed between the two urea concentrations.
Søren O Petersen; Peter Roslev; Roland Bol
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  70     ISSN:  0099-2240     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  2004 Nov 
Date Detail:
Created Date:  2004-11-05     Completed Date:  2005-02-28     Revised Date:  2013-04-18    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6363-9     Citation Subset:  IM    
Department of Agroecology, Danish Institute of Agricultural Sciences, Tjele, Denmark.
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MeSH Terms
Carbon Dioxide / metabolism
Carbon Isotopes / metabolism
Fatty Acids / metabolism
Nitrobacter / growth & development,  metabolism
Nitrosomonas / growth & development,  metabolism
Phospholipids / metabolism
Quaternary Ammonium Compounds / metabolism
Soil Microbiology*
Urea / metabolism*
Urine* / chemistry
Reg. No./Substance:
0/Carbon Isotopes; 0/Fatty Acids; 0/Phospholipids; 0/Quaternary Ammonium Compounds; 124-38-9/Carbon Dioxide; 57-13-6/Urea

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