Fire effect on lipid composition and hydrophobicity of sandy soils
Low soil-water affinity and soil water repellence (SWR, hydrophobicity) prevents water from wetting or infiltrating soils in burnt and unburnt ecosystems, causing changes on their hydrology, geomorphology, geochemistry, and biochemistry. A wildfire may destroy, develop or enhance SWR in previously wettable or water-repellent soils (e.g., Doerr et al., 2009; Jordán et al., 2013 and references therein). Hydrophobicity is at least in part attributed to a lipid-like cover, rich in fatty acids (FAs). Recently, we have shown that FAs had a major role in the water repellency observed in sandy soils in Doñana National Park (DNP, SW-Spain) under trees (Quercus suber, Pinus pinea) and shrubs (Pteridium aquilinum, Halimium halimifolium) vegetation (Jiménez-Morillo et al., 2016). To get further insight into how fire affect the distribution of soil lipids and their role in SWR, a study was performed on different size fractions of a DNP sandy soil under Quercus suber cover. Two soil samples were taken, one in a burnt site and another in an adjacent unburnt (control) one, both having the same physiographic characteristics. SWR was determined using water-drop-penetration-time test in the <2 mm sieved (bulk) soils and in six size fractions: 1-2 mm, 0.5-1 mm, 0.25-0.5 mm, 0.1-0.25 mm, 0.05-0.1 mm and <0.05 mm. Lipids were extracted from all samples (n = 14), and the FAs and neutral lipids identified and quantified by GC/MS and GC/FID, and the carbon isotope composition (¿13C values in ¿ vs. VPDB) of the individual saponifiable compounds determined by GC/C/IRMS.
| Main Authors: | , , , , , |
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| Format: | póster de congreso biblioteca |
| Published: |
European Association of Organic Geochemists
2017-09-17
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| Online Access: | http://hdl.handle.net/10261/163162 http://dx.doi.org/10.13039/501100003329 |
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| Summary: | Low soil-water affinity and soil water repellence (SWR, hydrophobicity) prevents water from wetting or infiltrating soils in burnt and unburnt ecosystems, causing changes on their hydrology, geomorphology, geochemistry, and biochemistry. A wildfire may destroy, develop or enhance SWR in previously wettable or water-repellent soils (e.g., Doerr et al., 2009; Jordán et al., 2013 and references therein). Hydrophobicity is at least in part attributed to a lipid-like cover, rich in fatty acids (FAs). Recently, we have shown that FAs had a major role in the water repellency observed in sandy soils in Doñana National Park (DNP, SW-Spain) under trees (Quercus suber, Pinus pinea) and shrubs (Pteridium aquilinum, Halimium halimifolium) vegetation (Jiménez-Morillo et al., 2016). To get further insight into how fire affect the distribution of soil lipids and their role in SWR, a study was performed on different size fractions of a DNP sandy soil under Quercus suber cover. Two soil samples were taken, one in a burnt site and another in an adjacent unburnt (control) one, both having the same physiographic characteristics. SWR was determined using water-drop-penetration-time test in the <2 mm sieved (bulk) soils and in six size fractions: 1-2 mm, 0.5-1 mm, 0.25-0.5 mm, 0.1-0.25 mm, 0.05-0.1 mm and <0.05 mm. Lipids were extracted from all samples (n = 14), and the FAs and neutral lipids identified and quantified by GC/MS and GC/FID, and the carbon isotope composition (¿13C values in ¿ vs. VPDB) of the individual saponifiable compounds determined by GC/C/IRMS. |
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