Estimation of the Origin of Dissolved Organic Matter and Biogeochemical Cycles of Nutrients in Osaka Bay, Japan

• KOBAYASHI Shiho

  Field Science Education and Research Center, Kyoto University

• MATSUMURA Yoshitaka

  Graduate School of Agriculture, Kyoto University

• KAWAMURA Koji

  Osaka Institute of Technology

• NAKAJIMA Masaki

  Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture

• YAMAMOTO Keigo

  Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture

• AKIYAMA Satoshi

  Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture

• UETA Yukio

  Tokushima Agriculture, Forestry, and Fisheries Technology Support Center

Bibliographic Information

Other Title

• 大阪湾における溶存有機物の起源推定および栄養塩の形態変化
• オオサカワン ニ オケル ヨウゾンユウキブツ ノ キゲン スイテイ オヨビ エイヨウエン ノ ケイタイ ヘンカ

Abstract

Modeling the processes by which dissolved inorganic nitrogen and phosphorus contribute to biological productivity would be of assistance in restoring the soundness of the material cycles and food web in semi-enclosed seas. In this study, field observations to investigate the biogeochemical cycle of nutrients and the spatial variations were conducted in Osaka Bay in August and November 2015 to obtain basic data for modeling. The observed results for a stable isotope of dissolved organic carbon showed that dissolved organic matter is generated in the bay in summer in addition to those supplied from rivers. The dissolved organic matter spreads along the conservative mixing line toward the shelf sea. These results suggested that dissolved inorganic nitrogen and phosphorus supplied from rivers were assimilated by phytoplankton and transformed into dissolved organic matter, a large part of which flowed out of the bay before degradation into inorganic matter. The abundance of heterotrophic bacteria and cyanobacteria, and the significant correlations between those and heterotrophic nanoflagellates suggested that a significant amount of nitrogen was taken into the microbial loop by heterotrophic bacteria feeding on dissolved organic matter and cyanobacteria consuming the nutrients.

Journal

• Journal of Japan Society on Water Environment

  Journal of Japan Society on Water Environment 40 (2), 97-105, 2017

  Japan Society on Water Environment

Keywords

• Semi-enclosed coastal seas
• Nutrients
• Stable isotope
• Dissolved organic matter
• Microbial loop

Details

• CRID: 1390282680057296000
• NII Article ID: 130005439533
• NII Book ID: AN10372439
• DOI: 10.2965/jswe.40.97
• ISSN: 18813690
• ISSN: 09168958
• NDL BIB ID: 028728566
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I028728566
• Web Site: https://www.jstage.jst.go.jp/article/jswe/40/2/40_97/_pdf
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed