Community dynamics and activity of nirS-harboring denitrifiers in sediments of the Indus River Estuary. (April 2020)

• Record Type: Journal Article
• Authors: Fozia, ; Zheng, Yanling; Hou, Lijun; Zhang, Zongxiao; Gao, Dengzhou; Yin, Guoyu; Han, Ping; Dong, Hongpo; Liang, Xia; Yang, Yi; Liu, Min
• Is Part Of: Marine pollution bulletin. Volume 153(2020)
• Publication Date: 2020-04
• Subjects: Denitrification -- Nitrogen -- nirS gene -- The Indus River Estuary; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2020.110971
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Denitrification is an important pathway for reactive nitrogen removal from aquatic ecosystems. In this study, the biodiversity, abundance, and activity of cytochrome cd 1 -type nitrate reductase gene ( nirS )-harboring denitrifiers in the sediments of the Indus River Estuary were examined by molecular and isotope-tracing techniques. Results showed that the nirS -harboring denitrifier communities showed significant geographical variations along the estuarine salinity gradient. Real-time quantitative PCR showed that the abundance of nirS -harboring denitrifiers ranged from 5.3 × 10 6 to 2.5 × 10 8 copies g −1, without significant spatiotemporal variation. The potential rates of denitrification varied from 0.01 to 6.27 μmol N kg −1 h −1 and correlated significantly to TOC and Fe(II) ( P < 0.05). On the basis of 15 N isotope-tracing experiments, the denitrification process contributed 18.4–99.4% to the total nitrogen loss in the sediments of the Indus River Estuary. This study provides novel insights into the microbial mechanism of nitrogen removal process in estuarine ecosystems. Graphical abstract: Unlabelled Image Highlights: nirS -type denitrifier community had significant spatial variation along the estuary. Abundance of nirS -type denitrifier ranged from 5.3 × 10 6 to 2.5 × 10 8 copies g −1 . The potential rates of denitrification varied from 0.01 to 6.27 μmol N kg −1 h −1 . Denitrification contributed up to 99% to total N loss in the Indus River Estuary.