Development and application of the compound specific isotope analysis of chlorophylls to elucidate nitrogen cycle in the ocean

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K12199
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: OGAWA Nanako O. 国立研究開発法人海洋研究開発機構, 生物地球化学研究分野, 主任技術研究員 (80359174)
• Co-Investigator(Renkei-kenkyūsha): YOSHIKAWA Chisato 国立研究開発法人海洋研究開発機構, 生物地球化学研究分野, 技術研究員 (40435839)
• Research Collaborator: SUGAHARA Haruna 国立研究開発法人海洋研究開発機構, 生物地球化学研究分野, ポストドクトラル研究員 (50735909)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: クロロフィル / 光合成 / 化合物レベル同位体比 / 海洋表層域 / 窒素循環 / 同位体物質循環モデル / 植物プランクトン

Outline of Final Research Achievements

In this study, to investigate the nitrogen cycle in the modern surface ocean, nitrogen isotopic compositions of chloropigments (chlorophyll and its derivatives) and nitrate in the natural ocean were determined. Chloropigments are a group of nitrogenous compounds produced only by the phototrophic primary producers. As directly involved to the photosynthetic process, and known to be preserved in the sediments for long time, nitrogen isotope information of chlorophyll is regarded to be one of the most useful tool to reconstruct and assess the biogeochemical nitrogen cycle in the surface ocean, both in present and in the past. Suspended particles and water samples were collected from photic zone of Indian Ocean and subtropical sites in the western Pacific Ocean. The observed were applied to the isotopic nitrogen model simulation to elucidate contribution balance of nutrient nitrogen as substrate to the phytoplankton photosynthesis and the nitrogen cycle in the surface ocean.

Free Research Field

生物地球化学