AME 55:105-113 (2009)  -  DOI: https://doi.org/10.3354/ame01285

ABSTRACT: We assayed sediment for the anammox reaction at 40 sites from 9 estuaries during the summer of 2004. The anammox reaction was detected at all sites with its potential contribution to the production of N₂ (ra, %) ranging from <1 to 11%. Overall, a higher contribution from anammox was positively correlated with both the concentration of NO₃^– in the overlying water and the organic carbon content of the sediment. Whilst the organic carbon content of the sediment decreased towards the coast, its reactivity remained essentially constant (k = 0.6 y^–1), which suggested that the amount of organic carbon rather than its reactivity or quality was more important. In addition, our large dataset enabled us to critically assess the 2 assays for measuring anammox (¹⁵NH₄⁺ or ¹⁵NO₃^–). While the 2 assays gave good agreement at ra > 3% (>2 nmol N₂ ml^–1 wet sediment for anammox after 24 h), below this, though still detectable, anammox was underestimated with ¹⁵NH₄⁺. The decrease in the estimate for anammox with ¹⁵NH₄⁺ relative to ¹⁵NO₃^– was partly explained by a decrease in the recovery of N₂ gas, probably as a result of significant dissimilatory nitrate reduction to ammonium (DNRA) in some of the slurries. The potential interference from DNRA in the anammox assay, however, would be low, with the probability of anamox making ³⁰N₂ (A³⁰N₂) being about 1.4%. Our findings provide firm evidence that the anammox reaction is widespread in estuarine sediments.

KEY WORDS: Anammox · Estuary · Sediment · Organic carbon · Nitrate

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Cite this article as: Nicholls JC, Trimmer M (2009) Widespread occurrence of the anammox reaction in estuarine sediments. Aquat Microb Ecol 55:105-113. https://doi.org/10.3354/ame01285 Export citation Share:    Facebook - - linkedIn