This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Aumen, N. G.
Right arrow Articles by Gregory, S. V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Aumen, N. G.
Right arrow Articles by Gregory, S. V.
Agricola
Right arrow Articles by Aumen, N. G.
Right arrow Articles by Gregory, S. V.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1985 May; 49(5): 1119-1123
Copyright © 1985, American Society for Microbiology. All Rights Reserved.

Nitrogen Dynamics in Stream Wood Samples Incubated with [14C]Lignocellulose and Potassium [15N]Nitrate {dagger}

Nicholas G. Aumen*,{ddagger}, Peter J. Bottomley and Stan V. Gregory

1 Departments of Microbiology, Soil Science, 2 and Fisheries and Wildlife, 3 Oregon State University, Corvallis, Oregon 97331-3804

ABSTRACT

Surface wood samples obtained from a Douglas fir log (Pseudotsuga menziesii) in a Pacific Northwest stream were incubated in vitro with [14C]lignocellulose in a defined mineral salts medium supplemented with 10 mg of N liter–1 of 15N-labeled NO3– (50 atom% 15N). Evolution of 14CO2, distribution and isotopic dilution of 15N, filtrate N concentrations, and the rates of denitrification, N2 fixation, and respiration were measured at 6, 12, and 18 days of incubation. The organic N content of the lignocellulose-wood sample mixture had increased from 132 µg of N to a maximum of 231 µg of N per treatment after 6 days of incubation. Rates of [14C]lignocellulose decomposition were greatest during the first 6 days and then began to decline over the remaining 12 days. Total CO2 evolution was also highest at day 6 and declined steadily over the remaining duration of the incubation. Filtrate NH4+-N increased from background levels to a final value of 57 µg of N per treatment. Filtrate NO3– N completely disappeared by day 6, and organic N showed a slight decline between days 12 and 18. The majority of the 15N that could be recovered appeared in the particulate organic fraction by day 6 (41 µg of N), and the filtrate NH4+ N fraction contained 11 µg of 15N by day 18. The 15N enrichment values of the filtrate NH4+ and the inorganic N associated with the particulate fraction had increased to approximately 20 atom% 15N by 18 days of incubation, whereas the particulate organic fraction reached its highest enrichment by day 6. Measurements of N2 fixation and denitrification indicated an insignificant gain or loss of N from the experimental system by these processes. The data show that woody debris in stream ecosystems might function as a rapid and efficient sink for exogenous N, resulting in stimulation of wood decomposition and subsequent activation of other N cycling processes.

FOOTNOTES

* Corresponding author.

{ddagger} Present address: Department of Biology, The University of Mississippi, University, MS 38677.

{dagger} Oregon State University Agricultural Experiment Station Technical Paper no. 7377.

Appl Environ Microbiol. 1985 May; 49(5): 1119-1123
Copyright © 1985, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»