Use of 16S rRNA-targeted oligonucleotide probes to investigate the distribution of sulphate-reducing bacteria in estuarine sediments

The distribution of sulphate-reducing bacteria (SRBs) in three anaerobic se diments, one predominantly freshwater and low sulphate and two predominantl y marine and high sulphate, on the River Tama, Tokyo, Japan, was investigat ed using 16S rRNA-targeted oligonucleotide probes. Hybridisation results an d sulphate reduction measurements indicated that SRBs are a minor part of t he bacterial population in the freshwater sediments. Only Desulfobulbus and Desulfobacterium were detected, representing 1.6% of the general bacterial probe signal. In contrast, the SRB community detected at the two marine-do minated sites was larger and more diverse, representing 10-11.4% of the bac terial signal and with Desulfobacter, Desulfovibrio, Desulfobulbus and Desu lfobacterium detected. Ia contrast to previous reports our results suggest that Desulfovibrio may not always be the most abundant SRB in anaerobic sed iments. Acetate-utilising Desulfobacter were the dominant SRB in the marine -dominated sediments, and Desulfobulbus and Desulfobacterium were active in low-sulphate sediments, where they may utilise electron acceptors other th an sulphate. (C) 2001 Federation of European Microbiological Societies. Pub lished by Elsevier Science B.V. All rights reserved.