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1997 Fiscal Year Final Research Report Summary

Secondary biological pump driven by food web interactions : A case study in Lake Biwa for gloval environmental issues

Research Project

Project/Area Number 08308031
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field Environmental dynamic analysis
Research InstitutionKYOTO UNIVERSITY

Principal Investigator

NAKANISHI Masami  Center for Ecological Research, Kyoto Univ., Professor, 生態学研究センター, 教授 (60025434)

Co-Investigator(Kenkyū-buntansha) SUGIYAMA Masato  Department of Natural Environment Sciences, Faculty of Integrated Hu Studies, Ky, 総合人間学部, 助教授 (10179179)
NAKAYAMA Eiitirou  School of environmental science, Shiga prefectural Univ., Associate Prof., 環境科学部, 助教授 (50108982)
OOKUBO Keizi  Faculty of environmental science and technology, Okayama Univ., Associate Profes, 環境理工学部, 助教授 (50135612)
URABE Zyoutarou  Center for Ecological Research, Kyoto Univ., Associate Professor, 生態学研究センター, 助教授 (50250163)
Project Period (FY) 1996 – 1997
KeywordsLake Biwa / sedimentation flux / biological production-decomposition / zooplankton / phytoplankton / bacteria / climate change / food chain
Research Abstract

To understando responses of aquatic ecosystems to global environmental change, we studied biological and decomposition processes in relation to environmental variables such as nutrients, light and water temperature, and relations between sedimentation flux of biological products and food chains.
1) Primary production of phytoplankton was limited by phosphorus in the layr above 5 m deep but by light intensity below 5 m deep. 2) Decomposition rate by bacteria was limited by phosphorus in the epilimnion and by water temperature in the hypolimnion.
3) Sedimentation flux corresponded with 12% of daily production of phytoplankton and most of the phytoplankton production were consumed by zooplankton and bacteria in the epilimnion. 4) 20-30% of the sedimentation flux were assimilated by Amphipoda gammarid in the aphotic zone. 5) The sedimentation flux changed seasonally depending on precipitation and propagation of microplanktonic algae such as Fragilaria crotonensis.
Biological production-decomposition rates and the sedimentation flux in Lake Biwa were strongly influensed by physical variable like light and water temperature, and food web structure. Further, they related closely to nutrients inflowing from rivers. These results suggest that climate change controlling precipitation, light, water temperature and nutrients influences directly acquatic ecosystems through processes of biological production-decomposition and vertical transportation of particulate organic matter.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Nakanishi, M.and T.Sekino: "Recent drastic changes in Lake Biwabio-Communities,with special attention to exploitation of the littoral zone." GeoJournal. 40.1-2. 63-67 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Urabe, J., J.Clasen and R.W.Sterner: "Phosphorus limitation of Daphnia growht:is it real?" Limnol.Oceanogr.,. 42:. 1436-1443 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Trevorrow, M.and Tanaka, Y.: "Acoustic and in-situ measurements of freshwater amphipods(Jesogam marus annandalei)in Lake Biwa,Japan" Limnol.Oceanogr.42(1). 121-132 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Tanaka, Y.and Tsuda, R.: "Daily fluctuations in thermal stratification,chlorophyll a,turb idity and dissolved oxygen concentration in Lake Biwa" Jap.J.Limnol.57,(4(2)). 377-393 (1997)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Nakanishi, M.and T.Sekino: "Recent drastic changes in LakeBiwa bio-communities, with special attention to exploitation of the littoral zone." GeoJournal. 40.1-2. 63-67 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Urabe, J., J.Clasen and R.W.Sterner: "Phosphorus limitation of Daphnia growht : is it real?" Limnol.Oceanogr.42. 1436-1443 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Trevorrow, M.and Tanaka, Y.: "Acoustic and in-situ measurements of freshwater amphipods (Jesogam marus annandalei) in Lake Biwa, Japan." Limnol.Oceanogr.42 (1). 121-132 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Tanaka, Y.and Tsuda, R.: "Daily fluctuations in thermal stratification, chlorophyll a, turb idity and dissolved oxygen concentration in Lake Biwa." Jap.J.Limnol. 57, (4(2)). 377-393 (1997)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-16  

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