Study on the mechanism of Metallogenium-particle formation at bottom layer of Lake Biwa and qualitative evaluation of the bottom environment

2016 Fiscal Year Final Research Report

• Project/Area Number: 26281042
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Modeling and technologies for environmental conservation and remediation
• Research Institution: Akita Prefectural University
• Principal Investigator: MIYATA Naoyuki 秋田県立大学, 生物資源科学部, 教授 (20285191)
• Co-Investigator(Kenkyū-buntansha): 古田 世子 滋賀県琵琶湖環境科学研究センター, その他部局等, 専門員 (00508476) ; 岡野 邦宏 秋田県立大学, 生物資源科学部, 助教 (30455927) ; 桐山 徳也 滋賀県琵琶湖環境科学研究センター, その他部局等, 専門員 (40723862) ; 高田 潤 岡山大学, 自然科学研究科, 特任教授 (60093259)
• Co-Investigator(Renkei-kenkyūsha): ICHISE Satoshi 滋賀県琵琶湖環境科学研究センター, 環境監視部門, 専門員 (10508443)
• Research Collaborator: IKEGAYA Hisato 兵庫県立大学, 生命理学研究科, 研究員 (30531579) ; FUJIBAYASHI Megumu 秋田県立大学, 生物資源科学部, 助教 (70552397)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: マンガン酸化細菌 / メタロゲニウム粒子 / 貧酸素化 / 底層部物質循環

Outline of Final Research Achievements

In the northern basin of Lake Biwa, the occurrence of filamentous Mn particles (Metallogenium-particles) at the bottom layer has been recorded since 2002. The aim of this study was to analyze the mechanism of Metallogenium particle formation in Mn(II)-oxidizing bacteria and to specify the conditions of bottom environment that bring about the particles formation. The results suggest that Mn(II)-oxidizing bacteria produce the Metallogenium particles under oxygen-limited, weekly acidic, and gelatinous polysaccharide-rich conditions. In the northern basin, polysaccharide-encapsulated phytoplankton cells grown in the upper layer go down and serve as resource of polysaccharides in the bottom layer.

Free Research Field

環境生物工学