Elucidation of Carbon Flow in Microbial Carbon Pump through Membrane Vesicles of Marine Bacteria

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K12145
• 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: University of Tsukuba
• Principal Investigator: Omori Yuko 筑波大学, 生命環境系, 助教 (80613497)
• Co-Investigator(Kenkyū-buntansha): 濱 健夫 筑波大学, 生命環境系, 名誉教授 (30156385) ; 豊福 雅典 筑波大学, 生命環境系, 准教授 (30644827)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 海洋炭素循環 / 微生物炭素ポンプ / 細胞外膜小胞 / 海洋細菌

Outline of Final Research Achievements

The behavior of extracellular membrane vesicles (MV) produced by marine bacteria was evaluated at the carbon level through 13C tracer incubation experiments using natural marine bacteria. It was shown that marine bacteria primarily produced MV after the growth phase, and these MVs remained without being degraded by bacteria. More than half of the bacterial-derived organic matter was suggested to be released into the seawater as dissolved form, with <10% present as MV. The observations in the coastal surface waters revealed that the organic carbon content of MV was very low.

Free Research Field

生物地球化学

Academic Significance and Societal Importance of the Research Achievements

海洋細菌が難分解性DOMを生成することで長期間海洋に有機炭素を貯留するプロセスは、地球表層の炭素循環ならびに気候変動に影響を及ぼすが、その有機炭素プールの形成過程はブラックボックスである。本研究は、海洋細菌が生成するMVに着目し、細菌が生成する有機物の一部はMVとして残存することから、細菌を由来する微小な粒子形成が海洋有機炭素プールの形成プロセスのひとつであることが示唆された。