ISSN:
1365-2427
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Biologie
Notizen:
1. The effects of solar radiation on bacterial and fungal growth on aquatic macrophyte detritus were studied in a microcosm experiment. Senescent leaves of Phragmites australis were incubated for 63 days in shallow water in the shade under photosynthetically active radiation (PAR) together with ultraviolet radiation, or under filters removing either ultraviolet B (UVB) or both UVB and ultraviolet A (UVA).2. Bacterial abundance and bacterial 3H-leucine incorporation in the water were measured, together with α- and β-D-glucosidase activity. In addition, bacterial abundance and fungal biomass associated with the litter were measured.3. The results indicate that both PAR and UVA affect the micro-organisms involved in the decomposition of leaf litter. The α/β-D-glucosidase activity ratio was less than one in irradiated and more than one in shaded microcosms, suggesting a change in the substrate dissolved organic matter composition towards more β- than α-glycosidic linkages as a result of solar radiation.4. Microcosms receiving UVB displayed a significantly higher β-D-glucosidase activity than shaded microcosms, and those exposed to PAR or PAR + UVA, demonstrating the potential importance of UVB radiation.5. The free-living bacteria tended to be dominated by filamentous forms in microcosms subject to solar radiation, especially PAR, and attached microbial communities showed a greater tendency to be dominated by bacteria in irradiated microcosms than in shaded microcosms.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1046/j.1365-2427.1999.00407.x
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