Estimation of stream ecosystems by <SUP>13</SUP>C and <SUP>15</SUP>N natural abundances

DOI 6 Citations 20 References
  • KOHZU Ayato
    Japan Science and Technology Agency, Kyoto University
  • KAWAGUCHI Yôichi
    Aqua Restoration Research Center, Public Works Research Institute
  • NUNOKAWA Masanori
    Department of Forest Science, Graduate School of Agriculture, Hokkaido University
  • NAKAMURA Futoshi
    Department of Forest Science, Graduate School of Agriculture, Hokkaido University

Bibliographic Information

Other Title
  • 標津川再生事業の概要と再蛇行化実験の評価　　炭素，窒素安定同位体自然存在比による河川環境の評価

Description

Stream restoration has been conducted in the Shibetsu River in northern Japan, which aims at the recovery of its river-floodplain ecosystem altered dramatically in the last 40 years. Well-designed monitoring before and after restoration should be conducted to evaluate the effects of the stream restoration on its ecosystem. An analysis of stable isotope ratios (δ-values) is one of the most effective methods for monitoring material cycling in river ecosystems. Because product δ-values are roughly dependent upon their source δ-values, we can trace material flows by comparing the δ-values of various compounds. In the first section of this review, we introduced a basic concept of the δ-value analysis by using an analogy from various diffusion patterns of salt water. The second section described how to calculate δ-values and discussed the difference between the analyses of natural stable isotope ratios and the tracer analyses (another powerful tool for material flow analysis). The third section presented the theoretical basis of mechanisms which change the δ-values. A product δ-value becomes different from its source δ-value in two kinds of processes: isotope exchange equilibrium and kinetic isotope fractionation. The magnitude of this difference (Δδ-value: δproduct-δsource) tells us about the processes and activities of the reactions. The fourth section introduced specific examples from the carbon and nitrogen δ-values (δ13C, δ15N) of aquatic organisms to infer the degree of eutrophication and carbon recycling at ecosystem levels as well as to determine food web structures and photosynthetic activities at biological interaction levels. In the fifth section, we presented the result of our study indicating differences in food web structure between a main-stream channel and oxbow lake in the Shibetsu River watershed when their δ13C and δ15N values of diverse aquatic organisms were compared. The advantages and limitations of the stable isotope analysis in environmental assessment were also discussed.

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Details 詳細情報について

  • CRID
    1390282679450024960
  • NII Article ID
    130004541684
  • DOI
    10.3825/ece.7.201
  • ISSN
    18825974
    13443755
    http://id.crossref.org/issn/13443755
  • Text Lang
    ja
  • Data Source
    • JaLC
    • Crossref
    • CiNii Articles
  • Abstract License Flag
    Disallowed

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