Denitrification, DNRA and anammox processes are described for the first time coexisting in a highly saline lake

Nicolas Valiente Parra, postdoctoral fellow at CBA, has published a new study in the journal Science of the Total Environment about nitrate removal pathways in a highly saline lake.

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The study involved incubations of water and sediment from the highly saline Pétrola Lake in Spain. This waterbody is eutrophic as a result of the continuous supply of inorganic nitrogen (N) from synthetic fertilizers. Using the 15N-isotope pairing technique, Valiente and his collaborators were able to determine NO3- sink processes. They demonstrate for the first time the coexistence of denitrification, DNRA (dissimilatory nitrate reduction to ammonium) and anammox (anaerobic ammonium oxidation) processes in a highly saline lake.

In addition, the contribution of each pathway was determined by oxygen and light conditions. Denitrification was the dominant N removal process when oxygen and/or light were present. As a result, unexpected high N2O emission rates were found in those treatments. In contrast, anoxia and darkness promoted NO3- reduction by DNRA combined with N loss by anammox.

These results highlight the role of coupled DNRA-anammox in N cycling in lake ecosystems, and how they can compete with denitrification and, therefore, restrict N2O emissions to the atmosphere.


The paper can be read here

Nicolas Valiente Parra, first author of the paper

Published Oct. 28, 2021 11:21 PM - Last modified Mar. 2, 2022 12:39 PM