Effects of organic amendments on sulfate reduction activity, H2 consumption, and H2 production in salt marsh sediments

Publisher Website
Google Scholar
Abstract
Sulfate reduction activity (SRA) was measured via the radioactive tracer (35SO4 =) technique in sediment samples from the Canary Creek Marsh in Lewes, Delaware. Basal levels of SRA ranged from 130 to 319 nmoles of sulfate reduced/gram dry sediment/hour. With the exception of lactate and formate, all organic acids tested resulted in no stimulation of SRA, whereas straight chain alcohols (C1-C4) all gave a significant increase in SRA. In addition, H2, glucose, and cellobiose caused a twofold or greater increase in SRA, while cellulose amendments did not alter SRA. Molybdate, an inhibitor of sulfate-reducing bacteria (SRB), caused a total inhibition in SRA. 2-Bromoethanesulfonic acid (BES), an inhibitor of methanogenic bacteria, caused a slight decrease in SRA. Hydrogen was not produced in detectable quantities in unamended samples but was produced in large amounts in glucose-amended samples. Hydrogen was rapidly consumed in unamended samples with molybdate additions causing a significant decrease in the rate of H2 consumption. A variety of organic amendments was found to stimulate H2 uptake. These studies suggest that SRB are stimulated by a large variety of organic amendments in situ and that SRB play a major role in maintaining low partial pressures of H2 in marsh sediments.