Effect of nitrate on sulfur transformations in sulfidogenic sludge of a marine aquaculture biofilter

Carsten Ulrich Schwermer, Timothy G. Ferdelman, Peter Stief, Armin Gieseke, Nastaran Rezakhani, Jaap Van Rijn, Dirk De Beer, Andreas Schramm

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The effect of NO3- addition on dissimilatory SO 42- reduction and sulfide conversion in organic-rich sludge from the digestion basin of a recirculating marine aquaculture system was studied. SO42- reduction could only explain a minor fraction (up to 4-9%) of the observed total sulfide production (up to 35 mmol L-1 day-1), indicating that the main source of sulfide in the sludge was not SO42- reduction, but desulfuration during the decomposition of organic matter. Although NO3- inhibited SO42- reduction, but not desulfuration, the primary NO3- mitigation effect was the onset of NO 3--mediated sulfide oxidation (up to 75 mmol L -1 day-1), partially to elemental sulfur (S0). Above NO3- concentrations of 0.6 mM in the bulk water, the net sulfide production and oxidation zones were moved deeper into flocs and sludge cores, which effectively prevented sulfide from entering the water column. However, the sulfide efflux from the sludge instantly recovered after NO3- depletion. Thus, the NO3- level in the water column controls the zonation and magnitude of sulfur transformations in the sludge. The effect of NO3- relies therefore on its sustained presence in the water column, which in turn depends on a well-functioning nitrification in the mariculture system.

Original languageAmerican English
Pages (from-to)476-484
Number of pages9
JournalFEMS Microbiology Ecology
Volume72
Issue number3
DOIs
StatePublished - Jun 2010

Keywords

  • Mariculture
  • Microsensors
  • Nitrate reduction
  • Sulfate reduction
  • Sulfide oxidation

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