DOI: 10.1073/pnas.0803763105
论文题名: In situ microbial metabolism as a cause of gas anomalies in ice
作者: Rohde R.A. ; Price P.B. ; Bay R.C. ; Bramall N.E.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2008
卷: 105, 期: 25 起始页码: 8667
结束页码: 8672
语种: 英语
英文关键词: Climate
; Ice cores
; N2O
; Proxy for dust storms
; Scanning fluorimetry
Scopus关键词: nitrogen oxide
; article
; flame photometry
; fluorescence analysis
; methanogen
; microbial metabolism
; priority journal
; spectrofluorometry
; turbulent flow
; Bacteria
; Fluorometry
; Greenland
; Ice Cover
; Methane
; Microscopy, Fluorescence
; Nitrogen Dioxide
; Temperature
; Water Microbiology
英文摘要: Isolated spikes of anomalously high concentrations of N2O have been reported at depths in Greenland and Antarctic ice cores corresponding to narrow time intervals over the past ≈105 years. Now, using a calibrated spectrofluorimeter to map protein-bound Trp, a proxy for microbes, versus depth in the 3,053-m GISP2 ice core, we find six depths at which localized spikes of high cell concentrations coincide with N2O spikes. We show that the excess gases are consistent with accumulation of in situ metabolic wastes during residence times of the excess microbes in the ice. Because of sparseness of N2O measurements and our spectrofluorimetry versus depth, the total number of microbially produced N2O spikes in GISP2 is probably much larger than six. Spikes of excess methanogens coincident with CH4 spikes are found at three depths in the bottom 3% of GISP2, most likely because of methanogenic metabolism in the underlying silty ice, followed by turbulent flow of the lowest ≈90 m of ice. The apparent rates of in situ production of N2O and CH4 spikes by metabolism are observed to be consistent with a single activation energy, U, and maintain proportionality to exp(-UIRT) over the entire temperature range down to -40°C. Fluorescence of nonmicrobial aerosols in GISP2 ice is distinguishable from microbial fluorescence by its different emission spectra. Our spectrof luorimetric scans throughout the GISP2 ice core lead us to conclude that both microbes and nonmicrobial aerosols are deposited in discontinuous bursts, which may provide a tool for studying wind storms in the distant past. © 2008 by The National Academy of Sciences of the USA. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/162462
Appears in Collections: 气候变化与战略
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作者单位: Rohde, R.A., Physics Department, University of California, Berkeley, CA 94720, United States; Price, P.B., Physics Department, University of California, Berkeley, CA 94720, United States; Bay, R.C., Physics Department, University of California, Berkeley, CA 94720, United States; Bramall, N.E., Physics Department, University of California, Berkeley, CA 94720, United States, National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA 14035, United States
Recommended Citation:
Rohde R.A.,Price P.B.,Bay R.C.,et al. In situ microbial metabolism as a cause of gas anomalies in ice[J]. Proceedings of the National Academy of Sciences of the United States of America,2008-01-01,105(25)