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Titel |
Experimental nitrogen, phosphorus, and potassium deposition decreases summer soil temperatures, water contents, and soil CO2 concentrations in a northern bog |
VerfasserIn |
S. Wendel, T. Moore, J. Bubier, C. Blodau |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 8, no. 3 ; Nr. 8, no. 3 (2011-03-07), S.585-595 |
Datensatznummer |
250005564
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Publikation (Nr.) |
copernicus.org/bg-8-585-2011.pdf |
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Zusammenfassung |
Ombrotrophic peatlands depend on airborne nitrogen (N), whose deposition has
increased in the past and lead to disappearance of mosses and increased
shrub biomass in fertilization experiments. The response of soil water
content, temperature, and carbon gas concentrations to increased nutrient
loading is poorly known and we thus determined these data at the long-term N
fertilization site Mer Bleue bog, Ontario, during a two month period in
summer. Soil temperatures decreased with NPK addition in shallow peat soil
primarily during the daytime (t-test, p < 0.05) owing to increased shading,
whereas they increased in deeper peat soil (t-test, p < 0.05), probably by
enhanced thermal conductivity. These effects were confirmed by RMANOVA,
which also suggested an influence of volumetric water contents as
co-variable on soil temperature and vice versa (p < 0.05). Averaged over all
fertilized treatments, the mean soil temperatures at 5 cm depth decreased by
1.3 °C and by 4.7 °C (standard deviation 0.9 °C) at noon.
Water content was most strongly affected by within-plot spatial heterogeneity but
also responded to both N and PK load according to RMANOVA (p < 0.05).
Overall, water content and CO2 concentrations in the near-surface peat
(t-test, p < 0.05) were lower with increasing N load, suggesting more rapid
soil gas exchange. The results thus suggest that changes in bog ecosystem
structure with N deposition have significant ramifications for physical
parameters that in turn control biogeochemical processes. |
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