Characteristics and behavior of refractory dissolved organic matter produced by bacteria in Lake Biwa

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K21105
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Civil and environmental engineering; Environmental dynamic analysis
• Research Institution: Kyoto University
• Principal Investigator: Kusakabe Taketoshi 京都大学, 工学研究科, 助教 (40462585)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 琵琶湖 / 溶存有機物 / 難分解性有機物 / 微生物群集 / 精密質量分析

Outline of Final Research Achievements

The refractory (non-biodegradable) organic matter has been increasing in lakes, and it is of crucial importance to understand the origin, characteristics, and behavior of natural organic matter. We focused on the refractory dissolved organic matter (R-DOM) produced by microbial communities, and the objective of this research is to demonstrate its chemical characteristics and behavior in the Lake Biwa watershed. The Orbitrap mass spectrometry with electrospray ionization (ESI) was applied to DOM in Lake Biwa and inflowing rivers, and DOM produced by microorganisms and bacterial strains from several organic substrates, e.g., glucose, glutamate, Microcystis aeruginosa. As a result, the role and function of microbial community in Lake Biwa are significant as production of Lake Biwa DOM. And, it was suggested that the contribution of allochthonous DOM is not small.

Free Research Field

環境動態解析

Academic Significance and Societal Importance of the Research Achievements

本研究では、微生物群集が介在する「微生物炭素ポンプ（microbial carbon pump）」が長期的な炭素貯留プロセスとして駆動していることに鑑みて、微生物食物網（microbial food web）の結節点として細菌が重要な鍵になると考え、微生物群集が産出する有機物に注目した。本研究で明らかとなった難分解性有機物の化学的描像や環境動態に関する知見は、湖沼における物質循環や水質形成メカニズムに対する理解の深化のみならず、健全な湖沼生態系の創出、持続可能な水利用、等々に資するものである。