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Moisture availability influences the effect of ultraviolet-B radiation on leaf litter decomposition.
- Source :
-
Global Change Biology . Jan2010, Vol. 16 Issue 1, p484-495. 12p. 3 Charts, 6 Graphs. - Publication Year :
- 2010
-
Abstract
- Altered surface ultraviolet-B (UV-B) radiation resulting from a combination of factors that include changes in stratospheric ozone concentrations, cloud cover, and aerosol conditions may affect litter decomposition and, thus, terrestrial nutrient cycling on a global scale. Although litter decomposition rates vary across biomes, patterns of decomposition suggest that UV-B radiation accelerates litter decay in xeric environments where precipitation is infrequent. However, under more frequent precipitation regimes where litter decay rates are characteristically high, the effect of UV-B radiation on litter decomposition has not been fully elucidated. To evaluate this association between moisture regime and UV-B exposure, a litter decomposition experiment was designed for aspen ( Populus tremuloides) leaf litter, where conditions that influence both abiotic (photodegradation) and biotic (microbial) processes could be manipulated quantitatively. We found that experimentally increasing UV-B exposure (0, 7.4, and 11.2 kJ m−2 day−1, respectively) did not consistently increase litter decomposition rates across simulated precipitation frequencies of 4, 12, and 24 days. Instead, a UV-B exposure of 11.2 kJ m−2 day−1 resulted in a 13% decrease in decomposition rates under the 4-day precipitation frequency, but an increase of 80% under the 24-day frequency. Furthermore, the same UV-B dose increased litter decomposition rates under the 24-day precipitation frequency by 78% even in conditions where microbial activity was suppressed. Therefore, under more xeric conditions, greater exposure to UV-B radiation increased decomposition rates, presumably through photodegradation. In contrast, when decomposition was not moisture-limited, greater UV-B exposure slowed decomposition rates, most likely from the resulting inhibition of microbial activity. Ultimately, these experimental results highlight UV-B radiation as a potential driver of decomposition, as well as indicate that both the direction and magnitude of the UV-B effect is dependent on moisture availability, a factor that may change according to future patterns in global precipitation. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13541013
- Volume :
- 16
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Global Change Biology
- Publication Type :
- Academic Journal
- Accession number :
- 45546412
- Full Text :
- https://doi.org/10.1111/j.1365-2486.2009.01973.x