C/N ratios in a sediment core from Nakaumi Lagoon, southwest Japan—usefulness as an organic source indicator

• Sampei Yoshikazu

  Department of Geoscience, Faculty of Science and Engineering, Shimane University

• Matsumoto Eiji

  Division of Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University

書誌事項

タイトル別名

• C/N ratios in a sediment core from Nakaumi Lagoon, southwest Japan. Usefulness as an organic source indicator.
• C/N ratios in a sediment core from Nakaumi Lagoon, southwest Japan—usefulness as an organic source indicator—

抄録

The weight ratio of total organic carbon to total nitrogen (C/N ratio) in 20 meters of sediment core from Nakaumi Lagoon (coastal brackish lake), Japan is examined for its suitability as an organic source indicator. The C/N ratio depth profile is compared to the depth profiles of other proxies, i.e., weight ratio of total organic carbon to total organic nitrogen (C/N_org. ratio), stanol compositions, n-alkane compositions and the hydrogen-index by Rock-Eval pyrolysis. The C/N ratios of the lagoonal sediments, which have been deposited over the last ca. 8, 000 years, have a different profile from that of the C/N_org. ratio and other proxies due to the effects of a constant level of inorganic nitrogen (N_inorg.: ca. 0.04%) in the sediments. When C_org. content is less than 1 wt%, the presence of N_inorg. lowers the C/N ratio considerably, giving an inaccurate indication of organic source. C-N and C/N ratio–C_org. plots are useful for evaluating the effect of N_inorg.; if the depth profiles of the C/N ratio and C_org. content exhibit similar trends, this is taken as a warning that the apparent variation in the C/N ratio should be carefully examined in conjunction with the other plots and proxies. It is also found that the C/N_org. ratio itself also tends to increase due to the preferential decomposition of nitrogen compounds, and that in sediments containing high proportions of planktonic organic matter (OM), the sensitivity of the C/N ratio to changes in the proportions of planktonic-terrestrial OM is relatively low.

収録刊行物

• ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ

  ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ 35 (3), 189-205, 2001

  一般社団法人日本地球化学会

キーワード

• Geochemistry and Petrology
• Geophysics

詳細情報

• CRID: 1390001204550260224
• NII論文ID: 130003904659
• NII論文ID: 10010161452
• NII書誌ID: AA00654975
• DOI: 10.2343/geochemj.35.189
• COI: 1:CAS:528:DC%2BD3MXkslWqsrs%3D
• ISSN: 18805973
• ISSN: 00167002
• ISSN: http://id.crossref.org/issn/00167002
• NDL書誌ID: 5812896
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I5812896
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可