Efficient nitrogen removal pathways and corresponding microbial evidence in tidal flow constructed wetlands for saline water treatment

Manping Zhang, Shanshan Sun, Xushun Gu, Yuanyuan Peng, Pan Yan, Jung Chen Huang, Shengbing He, Xiaohui Bai, Yun Tian, Yang Hu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The artificial tidal wetlands ecosystem was believed to be a useful device in treating saline water, and it played a significant part in global nitrogen cycles. However, limited information is available on nitrogen-cycling pathways and related contributions to nitrogen loss in tidal flow constructed wetlands (TF-CWs) for saline water treatment. This study operated seven experimental tidal flow constructed wetlands to remove nitrogen from saline water at salinities of 0–30‰. Stable and high NH4+-N removal efficiency (∼90.3%) was achieved, compared to 4.8–93.4% and 23.5–88.4% for nitrate and total nitrogen (TN), respectively. Microbial analyses revealed the simultaneous occurrence of anaerobic ammonium oxidation (anammox), dissimilatory nitrate reduction to ammonium (DNRA), nitrification and denitrification, contributing to nitrogen (N) loss from the mesocosms. The absolute abundances were 5.54 × 103–8.35 × 107 (nitrogen functional genes) and 5.21 × 107–7.99 × 109 copies/g (16S rRNA), while the related genera abundances ranged from 1.81% to 10.47% (nitrate reduction) and from 0.29% to 0.97% (nitrification), respectively. Quantitative response relationships showed ammonium transformation were controlled by nxrA, hzsB and amoA, and nitrate removal by nxrA, nosZ and narG. Collectively, TN transformation were determined by narG, nosZ, qnorB, nirS and hzsB through denitrification and anammox pathways. The proportion of nitrogen assimilation by plants was 6.9–23.4%. In summary, these findings would advance our understanding of quantitative molecular mechanisms in TF-CW mesocosms for treating nitrogen pollution that caused algal blooms in estuarine/coastal ecosystems worldwide.

Original languageEnglish
Article number116548
JournalEnvironmental Research
Volume234
DOIs
Publication statusPublished - 2023 Oct 1

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • General Environmental Science

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