식생이 존재하하거나 존재하지 않는 연안 갯벌에서 Delta-proteobacteria의 군집과 미생물 분해경로의 연관성

Abstract

The objectives of this study were to relate the major pathways of anaerobic microbial respiration to molecular phylogenetic evidence in the unvegetated mudflat (UMF) and vegetated mudflat (VMF) vegetated by Suaeda japonica in the intertidal sediments in South Korea. Depth integrated C mineralization rates were 5 times higher at VMF (351mmol C m-2 d-1) in comparison to UMF (73mmol C m-2 d-1). Dissimilatory sulfate-and Fe(III) reduction accounted for 49.3% and 35.6%, respectively, of anaerobic C oxidation at UMF site, but represented 19.9% and 37.3%, respectively at VMF site. Among the clones related to dalta- proteobacteria, phylotypes affiliated with known Fe(III) or S0 reducing bacteria (Desulfuromonas/Pelobacter) were abundant in clone libraries from UMF(32.4%) and VMF(48.6%) sediments at deeper depths, whereas sequence closely related to sulfate reducers (Desulfobacterium and Desulfobulbus) were retrieved from all depths of the sediments sampled. Interestingly, a major fraction(56.2%; 18 among 32 clones) of the uncultures Desulfuromonas/Pelobacter group was observed in the rhizosphere of VMF site (VMF-5cm co). Therefore, the enhanced significance of Fe(III) reduction to C oxidation at the VMF site paralleled with the molecular phylogenetic analysis of the delta-proteobacteria.