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Titel |
Eutrophication and warming effects on long-term variation of zooplankton in Lake Biwa |
VerfasserIn |
C. H. Hsieh, Y. Sakai, S. Ban, K. Ishikawa, T. Ishikawa, S. Ichise, N. Yamamura, M. Kumagai |
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. 5 ; Nr. 8, no. 5 (2011-05-30), S.1383-1399 |
Datensatznummer |
250005828
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Publikation (Nr.) |
copernicus.org/bg-8-1383-2011.pdf |
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Zusammenfassung |
We compiled and analyzed long-term (1961–2005) zooplankton community data in
response to environmental variations in Lake Biwa. Environmental data
indicate that Lake Biwa had experienced eutrophication (according to the total
phosphorus concentration) in the late 1960s and recovered to a normal
trophic status around 1985, and then has exhibited warming since 1990. Total
zooplankton abundance showed a significant correlation with total
phytoplankton biomass. Following a classic pattern, the cladoceran/calanoid and
cyclopoid/calanoid abundance ratio was related positively to eutrophication.
The zooplankton community exhibited a significant response to the boom and bust
of phytoplankton biomass as a consequence of
eutrophication-reoligotriphication and warming. Moreover, our analyses
suggest that the Lake Biwa ecosystem exhibited a hierarchical response
across trophic levels; that is, higher trophic levels may show a more
delayed response or no response to eutrophication than lower ones.
We tested the hypothesis that the phytoplankton community can better explain the
variation of the zooplankton community than bulk environmental variables,
considering that the phytoplankton community may directly affect the zooplankton
succession through predator-prey interactions. Using a variance partition
approach, however, we did not find strong evidence to support this
hypothesis. We further aggregated zooplankton according to their feeding
types (herbivorous, carnivorous, omnivorous, and parasitic) and taxonomic
groups, and analyzed the aggregated data. While the pattern remains similar,
the results are less clear comparing the results based on finely
resolved data. Our research suggests that zooplankton can be bio-indicators
of environmental changes; however, the efficacy depends on data resolution. |
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