Abstract
The distribution of sulfate-reducing bacteria (SRB) was investigated in the sediments below fish cages used for torafugu (Takifugu rubripes) aquaculture along the coast of southern Fukui Prefecture, Japan. A quantitative competitive PCR targeting the gene coding for a portion of the α-subunit of the dissimilatory (bi)sulfite reductase (dsrA) gene was used to determine the distribution of SRB in the sediments. In unpolluted fish farm sediments, SRB were detected at levels of 0.5–8.4×108 cells g−1 dry sediment; whereas higher densities of SRB were found in sediments rich in organic matter and sulfide at levels of 0.8–4.4×109 cells g−1 dry sediment as determined by competitive PCR. We detected differences in SRB densities in fish farm sediments with different pollution levels, or organic contamination and sulfide content, suggesting SRB cell density may be used as an indicator of pollution levels in fish farm sediments as an adjunct to chemical analyses such as measurements of chemical oxygen demand (COD) or chemically determined total sulfide (TS).
