Contribution of photosynthesis of black spruce under soil-frozen condition on the annual CO2 budget

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K03998
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17030:Human geosciences-related
• Research Institution: Osaka Metropolitan University (2022); Osaka Prefecture University (2019-2021)
• Principal Investigator: Harazono Yoshinobu 大阪公立大学, 大学院農学研究科, 客員研究員 (90137240)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 光合成 / 根圏凍結 / クロトウヒ / 温暖化予測 / 光合成開始(On-Set ) / 炭素収支 / 不凍水

Outline of Final Research Achievements

A photosynthesis measurement system was installed in the forest at the University of Alaska Fairbanks to verify the photosynthesis of black spruce at sub-zero temperatures. The university campus was closed due to the spread of the new coronavirus infection, and the scheduled measurement from March was canceled for two and a half years.
n early April 2022, we resumed observation activities at the site. There was about 1 m of snow at the observation site. Sensors and control devices of chamber system were damaged during two and half years blank. In October 2022, I fixed the wiring of the data logger and the tubing, replaced some of the sensors, and tried to acquire preliminary photosynthesis data. However, the flow-regulating mass flow controller (MFC), which is essential for photosynthesis measurement, did not work completely, and the autumn research was finished without obtaining any preliminary data that could be used for the research.

Free Research Field

生態系の微気象

Academic Significance and Societal Importance of the Research Achievements

高緯度生態系の光合成開始時期（ON-Set）は陸域の炭素収支に重要である。本研究は根圏が凍結し水利用が困難な環境で，光合成が始まっていることを実証する試みである。先行研究で従来のOn-Set以前の光合成開始を把握したので，本研究では反復回数を増やし不凍水による光合成の可能性を実証する計画であったが，2年半に及ぶ学内入構制限のため期間内に実施できなかった。
凍土凍結中の光合成開始によりCO2 固定が増加することから，生態系の炭素固定量の詳細把握につながり，地球温暖化予測モデルの精度向上に有益情報であると共に，人為的排出量の削減指標策定など政策的にも重要な知見を得る予定であった。