Insight into the Inhibition of the Poisonous Sulfide Production from Sulfate-Reducing Microbiota in Mariculture Habitat

The production of toxic sulfides is a common environmental problem in mariculture. Therefore, the effective inhibition of sulfidogens is the key to prevent sulfides production. In this study, the possibility and mechanism of nitrate (NO3-) inhibiting the activity of the sulfate-reducing microbiota (SRM) from mariculture sediments was investigated. The results showed that 1, 3, and 5 mmol L-1 NO3- continuously inhibited sulfide production for 1-3 d. As NO3- dosage increased to 7 mmol L-1, the duration of inhibition increased to 6 days. Denitrifying product NO2- heavily inhibited the activity of dissimilar sulfate reductase gene (dsrB) by 3 orders, which was the main reason that the sulfate-reducing activity was inhibited. The SRM structure changed significantly with the dosage of NO3-, while the abundance of sulfidogens Desulfovibrio species increased due to their capability of detoxifying nitrite through nitrite reductase. Hence, sulfidogens Desulfovibrio species are more adaptable to a high nitrate/nitrite environment, and the traditional control strategies by dosing nitrate/nitrite should be paid more attention to. The findings will serve as helpful guidelines for sulfate-reducing microbiota in the habitat of mariculture to reduce their generation of poisonous sulfide.