Monitoring observation aimed at elucidating of a new phenomena in the phytoplankton community dynamics using the optical measurement methods

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K12311
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: The University of Shiga Prefecture
• Principal Investigator: GOTO Naoshige 滋賀県立大学, 環境科学部, 教授 (40336722)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 植物プランクトン / 一次生産 / 栄養塩 / 琵琶湖

Outline of Final Research Achievements

It is clarified by mooring, ship and satellite observation that community dynamics of phytoplankton (biomass, species composition, primary production) was greatly affected by a meteorological phenomena each year in the north basin of Lake Biwa. In particularly, strengthening and lengthening in the stratification, which is thought to be caused by global warming, decreases the supply of nutrients from deep layer to surface layer, resulting the fall phytoplankton bloom has become smaller compared with other year. In addition, the supply of nutrients from the inside and outside of Lake Biwa is almost cut off when the strengthened and lengthened stratification together with a decrease in precipitation. These phenomena caused the dominance of smaller-celled phytoplankton in Lake Biwa. Optical measurement methods that enable high-resolution spatiotemporal observation are expected to continue to show a new community dynamics of phytoplankton in Lake Biwa.

Free Research Field

環境動態解析、陸水学、生物地球化学

Academic Significance and Societal Importance of the Research Achievements

本研究では、温暖化に起因する水循環の停滞が、栄養塩動態の変化を介して、琵琶湖北湖の植物プランクトン群集に大きく影響することを示した。温暖化の進行は、琵琶湖における大型植物プランクトンの秋季ブルームを消失させ、一次生産力の低下を引き起こす可能性がある。これらの研究成果は、今後の温暖化に対する湖沼生態系の応答や保全・修復を考える上で重要な知見である。