Anaerobic ammonium oxidation coupled to iron(III) reduction (termed Feammox) is a recently discovered pathway of nitrogen cycling. However, little is known about the pathways of N transformation via Feammox process in riparian zones. In this study, evidence for Feammox in riparian zones with or without vegetation cover was demonstrated using isotope tracing technique and high-throughput sequencing technology. The results showed that Feammox could occur in riparian zones, and demonstrated that N2 directly from Feammox was dominant Feammox pathway. The Feammox rates in vegetated soil samples was 0.32–0.37 mg N kg⁻¹ d⁻¹, which is higher than that in un-vegetated soil samples (0.20 mg N kg⁻¹ d⁻¹). Moreover, the growth of vegetation led to a 4.99–6.41% increase in the abundance of iron reducing bacteria (Anaeromyxobacter, Pseudomonas and Geobacter) and iron reducing bacteria play an essential role in Feammox process. An estimated loss of 23.7–43.9 kg N ha⁻¹ year⁻¹ was associated with Feammox in the examined riparian zone. Overall, the co-occurrence of ammonium oxidation and iron reduction suggest that Feammox can play an essential role in the pathway of nitrogen removal in riparian zones.

The Djerdap 1 Hydropower Plant (Djerdap 1 HPP) was joint projects of Yugoslavia and Romania, based upon the principles of equal benefits. The primary functions of the Djerdap 1 HPP are to effectively utilize the available hydropower potential of the Danube and to provide a full navigational capability under any hydrologic conditions. The utilization of the hydropower potential was conditional upon the provision of a Riparian Land Protection System for the Djerdap 1 reservoir, and the timely prevention of any adverse impacts due to the alternation of the natural regime as a result of backwater. ongoing enhancement of the Riparian Land Protection System and study of the various impacts have enabled a continual backwater increase and a resulting increase in the output of high quality power, with no significant risk of adverse impacts.