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Solar radiation effects on decomposition of macrophyte litter in a lake littoral

Denward, C M T; Anesio, Alexandre Magno LU ; Granéli, Wilhelm LU and Tranvik, L J (2001) In Archiv für Hydrobiologie 152(1). p.69-80
Abstract
Ambient solar radiation effects on Phragmites australis leaf and culm litter were investigated in a shallow and eutrophic south Swedish lake littoral. Leaf and culm litter was exposed to natural sunlight in the lake at a water depth of a few centimeters. For the leaf litter, an additional subset of the experiment was exposed to solar radiation in the air, to evaluate effects of the solar radiation on the leaf litter in a dry state. Radiation treatments (shaded, photosynthetic active radiation [PAR], PAR + ultraviolet-A [UVA] and PAR + UVA + ultraviolet-B [UVB]) were achieved by screening with Plexiglas and Mylar film. Decomposition was measured as dry weight loss, and fungal and bacterial abundance on the detritus was estimated as... (More)
Ambient solar radiation effects on Phragmites australis leaf and culm litter were investigated in a shallow and eutrophic south Swedish lake littoral. Leaf and culm litter was exposed to natural sunlight in the lake at a water depth of a few centimeters. For the leaf litter, an additional subset of the experiment was exposed to solar radiation in the air, to evaluate effects of the solar radiation on the leaf litter in a dry state. Radiation treatments (shaded, photosynthetic active radiation [PAR], PAR + ultraviolet-A [UVA] and PAR + UVA + ultraviolet-B [UVB]) were achieved by screening with Plexiglas and Mylar film. Decomposition was measured as dry weight loss, and fungal and bacterial abundance on the detritus was estimated as ergosterol and bacterial numbers, respectively. We found no differences in either weight loss or bacterial abundance among radiation treatments. The fungal biomass in the dry leaf litter was unaffected by the radiation. In the wet leaf litter, however, the ergosterol content in PAR, PAR + UVA and PAR + UVA + UVB treated samples was about one third of the amounts found in the initial material and in the samples kept darkened. Similarly, the fungal biomass associated with the culm litter was negatively affected by solar PAR + UVA + UVB radiation, but in culms exposed only to PAR or to PAR + UVA it was not significantly different from the fungal biomass in darkened samples. These results suggest that the net effects of radiation differ between fungi and bacteria, with the fungi being more susceptible to suppression by solar radiation than the bacteria. Our experiments mimic more closely than previously published studies the conditions that can be expected in natural environments. Hence, we propose that previous reports of strong radiation effects on aquatic liner degradation should be applied very carefully to natural conditions. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
in
Archiv für Hydrobiologie
volume
152
issue
1
pages
69 - 80
publisher
E. Schweizerbart Science Publishers
external identifiers
  • scopus:0034890696
ISSN
0003-9136
language
English
LU publication?
yes
id
755526ba-95c2-48a0-8e39-e272fcae1fb3 (old id 146628)
date added to LUP
2007-06-28 13:07:35
date last changed
2018-05-29 10:42:33
@article{755526ba-95c2-48a0-8e39-e272fcae1fb3,
  abstract     = {Ambient solar radiation effects on Phragmites australis leaf and culm litter were investigated in a shallow and eutrophic south Swedish lake littoral. Leaf and culm litter was exposed to natural sunlight in the lake at a water depth of a few centimeters. For the leaf litter, an additional subset of the experiment was exposed to solar radiation in the air, to evaluate effects of the solar radiation on the leaf litter in a dry state. Radiation treatments (shaded, photosynthetic active radiation [PAR], PAR + ultraviolet-A [UVA] and PAR + UVA + ultraviolet-B [UVB]) were achieved by screening with Plexiglas and Mylar film. Decomposition was measured as dry weight loss, and fungal and bacterial abundance on the detritus was estimated as ergosterol and bacterial numbers, respectively. We found no differences in either weight loss or bacterial abundance among radiation treatments. The fungal biomass in the dry leaf litter was unaffected by the radiation. In the wet leaf litter, however, the ergosterol content in PAR, PAR + UVA and PAR + UVA + UVB treated samples was about one third of the amounts found in the initial material and in the samples kept darkened. Similarly, the fungal biomass associated with the culm litter was negatively affected by solar PAR + UVA + UVB radiation, but in culms exposed only to PAR or to PAR + UVA it was not significantly different from the fungal biomass in darkened samples. These results suggest that the net effects of radiation differ between fungi and bacteria, with the fungi being more susceptible to suppression by solar radiation than the bacteria. Our experiments mimic more closely than previously published studies the conditions that can be expected in natural environments. Hence, we propose that previous reports of strong radiation effects on aquatic liner degradation should be applied very carefully to natural conditions.},
  author       = {Denward, C M T and Anesio, Alexandre Magno and Granéli, Wilhelm and Tranvik, L J},
  issn         = {0003-9136},
  language     = {eng},
  number       = {1},
  pages        = {69--80},
  publisher    = {E. Schweizerbart Science Publishers},
  series       = {Archiv für Hydrobiologie},
  title        = {Solar radiation effects on decomposition of macrophyte litter in a lake littoral},
  volume       = {152},
  year         = {2001},
}