| Autor: |
Sylvie Drahorad, Peter Felix-Henningsen, K.-U. Eckhardt, P. Leinweber |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Journal of Arid Environments. 94:18-26 |
| ISSN: |
0140-1963 |
| DOI: |
10.1016/j.jaridenv.2013.02.006 |
| Popis: |
In arid and semi-arid areas biological soil crusts are main contributors to C and N-cycles and the origin of organic matter. Nevertheless systematic studies on the spatial distribution of total organic carbon (TOC) and nitrogen (N) and a characterization of crust organic matter composition are missing. To describe the spatial distribution of TOC and N we examined three soil depths and three relief positions along a steep rainfall gradient. In addition the molecular composition of organic matter was characterized by Pyrolysis-field ionization mass spectrometry. TOC and N concentrations decreased with increasing depth, the effects of the relief followed no clear trend. Surprisingly the amount of TOC and N decreased with increasing rainfall. Stable organic matter compounds were reduced with increasing rainfall. Topcrusts (0–2 mm) showed a relative enrichment in bacteria, as indicated by proportionally larger contents in N-acetylmuramic acid (m/z 167 + 276) than the subcrusts (2–40 mm). These were enrichment in cyanobacteria, as indicated by proportionally larger contents of hexadecadienoic acid (m/z 252). We conclude that the spatial distribution of TOC and N is related to sampling depth and annual precipitation. Organic matter composition and the main biomass contributors in crusts are successfully identified by pyrolysis-field ionization mass spectrometry. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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