脂肪酸組成分析を利用した内湾一次生産の制限因子の評価  [in Japanese] EVALUATION OF LIMITING FACTORS OF PRIMARY PRODUCTION OF INNER BAY USING FATTY ACID COMPOSITION ANALYSIS  [in Japanese]

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Abstract

内湾海水に対する栄養塩・金属類の添加培養試験に脂肪酸組成分析を組み合わせ,複数の一次生産者分類群の制限因子を一括で特定することを試みた.2017年9月に志津川湾より採取した海水について評価した結果,POCやクロロフィル <i>a</i>の生産の主たる制限因子は窒素であることが示された.脂肪酸組成分析からは,窒素添加が特に細菌または藍藻による粒子生産を顕著に増大させたこと,珪藻・渦鞭毛藻・緑藻に由来する脂肪酸の生産はリン制限であったことが示された.本手法により,陸域から負荷される物質組成の変化に対する内湾一次生産者の応答の予測に有用であることが示された.今後,マーカー脂肪酸の保存性などを明らかにし本手法により適正な評価が行える条件を引き続き検討する必要がある.

 We propose a new method to simultaneously identify limiting factors for productions of multiple primary producer types in costal planktonic communities. This method combines fatty acid composition analysis with conventional algal growth potential tests in which various combinations of nutrient and metal species are added to coastal waters. For seawater collected from Shizugawa bay in September 2017, it was shown that the production of POC and chlorophyll a were primarily limited by nitrogen. The fatty acid composition analysis indicated that nitrogen addition markedly increased particle productions especially by bacteria or cyanobacteria. Meanwhile, the productions of fatty acid markers of diatoms, dinoflagellates and green algae remarkably increased by phosphorus addition, so production of those algal groups seems to be limited by phosphorus rather than nitrogen. Overall, our method has great potential to bring useful knowledge to help to predict responses of inner bay primary producers to changes in material compositions loaded from watersheds. Concerning the preservability of the marker fatty acid composition, further study is necessary.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research)

    Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) 74(7), III_53-III_61, 2018

    Japan Society of Civil Engineers

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