Initial characterization of processes of soil carbon stabilization using forest stand-level radiocarbon enrichment [electronic resource].
- Published
- Washington, D.C. : United States. Dept. of Energy, 2004.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Physical Description
- PDF-file: 32 pages; size: 0.4 Mbytes
- Additional Creators
- Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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- Restrictions on Access
- Free-to-read Unrestricted online access
- Summary
- Although the rates and mechanisms of soil organic matter (SOM) stabilization are difficult to observe directly, radiocarbon has proven an effective tracer of soil C dynamics, particularly when coupled with practical fractionation schemes. To explore the rates of C cycling in temperate forest soils, we took advantage of a unique opportunity in the form of an inadvertent stand-level ¹⁴C-labeling originating from a local industrial release. A simple density fractionation scheme separated SOM into inter-aggregate particulate organic matter (free light fraction, free LF), particulate organic matter occluded within aggregates (occluded LF), and organic matter that is complexed with minerals to form a dense fraction (dense fraction, DF). Minimal agitation and density separation was used to isolate the free LF. The remaining dense sediment was subjected to physical disruption and sonication followed by density separation to separate it into occluded LF and DF. The occluded LF had higher C concentrations and C:N ratios than the free LF, and the C concentration in both light fractions was ten times that of the DF. As a result, the light fractions together accounted for less than 4% of the soil by weight, but contained 40% of the soil C in the 0-15 cm soil increment. Likewise, the light fractions were less than 1% weight of the 15-30 cm increment, but contained more than 35% of the soil C. The degree of SOM protection in the fractions, as indicated by Δ¹⁴C, was different. In all cases the free LF had the shortest mean residence times. A significant depth by fraction interaction for ¹⁴C indicates that the relative importance of aggregation versus organo-mineral interactions for overall C stabilization changes with depth. The rapid incorporation of ¹⁴C label into the otherwise depleted DF shows that this organo-mineral fraction comprises highly stable material as well as more recent inputs.
- Report Numbers
- E 1.99:ucrl-jrnl-201893
ucrl-jrnl-201893 - Subject(s)
- Other Subject(s)
- Note
- Published through SciTech Connect.
01/15/2004.
"ucrl-jrnl-201893"
Geoderma 128 1-2 ISSN 0016-7061; GEDMAB FT
Garten, C T; Hanson, P J; Torn, M S; Southon, J R; Hanlon, E M; Swanston, C W; Ganio, L. - Funding Information
- W-7405-ENG-48
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