식생이 존재하는 강화도 갯벌에서 미생물 다양성과 황산염, 철 환원력

Abstract

The objective of this study was to elucidate microbial community structure associated with the sulfate- and Fe(III) reduction in an unvegetated mud flat (UMF) and a vegetated mud flat (VMF) of the Ganghwa intertidal sediments, Korea. Sulfate- and Fe(III) reduction together comprised 105% and 72% of C oxidation at the UMF and VMF, respectively. Depth-integrated sulfate reduction rates at the VMF (63 mmol m-2d-1) were 3.5 times higher than at the UMF (18 mmol m-2d-1), and dissimilatory Fe(III) reduction rates were 5 times higher at the VMF (507 mmol m-2d-1) than at the UMF (103 mmol m-2d-1). Cloning and sequencing of 16S rRNA gene sequences retrieved in clone libraries from 0-1 cm and 5-6 cm depth (rhizosphere) intervals revealed that clones related to δ-Proteobacteria, including major groups of the sulfate- and Fe(III) reducing bacteria, comprised the largest fraction (25%). Diverse phylotypes related to sulfate-reducing bacteria (Desulfobacterium, Desulfobulbus, and Desulfosarcina) were retrieved from the VMF rhizosphere, whereas only a single Desulfobacterium clone type was observed at a comparable depth (5-6 cm) at UMF. In addition, clone sequences affiliated with Fe(III)/So reducing bacteria (Desulfuromonas/Pelobacter) comprised a large percentage (56.2%; 18 among 32 clones) of the clone library from the VMF rhizosphere. Overall results indicated that dense vegetation supplies organic C substrates and electron acceptors to the rhizosphere, thereby supporting enhanced C respiration by diverse groups of sulfate- and Fe(III) reducing bacteria at the VMF.