Fig. 1: Functional characteristics and injection reaction kinetics of the estuary sediments.
From: Versatile nitrate-respiring heterotrophs are previously concealed contributors to sulfur cycle
a Assessment of sulfate reduction activity in estuary sediment microcosms (three biological replicates). Sediment was incubated with anoxic overlying water. b Quantification of gene copies of biomarkers associated with sulfate reduction, sulfide oxidation, and nitrate reduction in sediments using qPCR. Nitrate reduction includes both denitrification and dissimilatory nitrate reduction to ammonium (DNRA) processes. All gene copies are represented per gram of dry sediment across three experimental replicates. Biomarkers include: dsrA, dissimilatory sulfite reductase subunit A; sqr, sulfide:quinone oxidoreductase; napA, cytochrome nitrate reductase; narG, nitrate reductase subunit alpha; nirS, cytochrome-cd1 nitrite reductase; nirK, copper-containing nitrite reductase; norB, nitric oxide reductase subunit B; nosZ, nitrous oxide reductase, and nrfA, ammonium-producing cytochrome c−552 nitrite reductase. c Nitrate reduction facilitated by the provision of nitrate and sulfide (three biological replicates). The blue circles illustrate the consumption of sulfide upon its supplementation. Sulfide levels in the incubation without the supplementation of sulfide are below detection. d Nitrate reduction facilitated by the provision of nitrate and organic matter (OM) (three biological replicates). OM is supplied once the nitrate reduction reaches a slow consumption rate. Atom concentrations of sulfur and nitrogen compounds are represented. All data are presented as mean values ± SEM. Source data are provided as a Source Data file.
