scholarly journals Effects of Sulfamethoxazole and 2-Ethylhexyl-4-Methoxycinnamate on the Dissimilatory Nitrate Reduction Processes and N2O Release in Sediments in the Yarlung Zangbo River

2020 ◽  
Vol 17 (6) ◽  
pp. 1822 ◽  
Author(s):  
Huiping Xu ◽  
Guanghua Lu ◽  
Chenwang Xue
Keyword(s):  
High Altitude ◽  
Nitrate Reduction ◽  
River Sediments ◽  
Nitrogen Transformation ◽  
Emerging Pollutants ◽  
15N Tracer ◽  
Ammonium Oxidation ◽  
Reduction Processes ◽  
Dissimilatory Nitrate Reduction ◽  
Yarlung Zangbo River

The nitrogen pollution of rivers as a global environmental problem has received great attentions in recent years. The occurrence of emerging pollutants in high-altitude rivers will inevitably affect the dissimilatory nitrate reduction processes. In this study, sediment slurry experiments combined with 15N tracer techniques were conducted to investigate the influence of pharmaceutical and personal care products (alone and in combination) on denitrification and the anaerobic ammonium oxidation (anammox) process and the resulting N2O release in the sediments of the Yarlung Zangbo River. The results showed that the denitrification rates were inhibited by sulfamethoxazole (SMX) treatments (1–100 μg L−1) and the anammox rates decreased as the SMX concentrations increased, which may be due to the inhibitory effect of this antibiotic on nitrate reducing microbes. 2-Ethylhexyl-4-methoxycinnamate (EHMC) impacted nitrogen transformation mainly though the inhibition of the anammox processes. SMX and EHMC showed a superposition effect on the denitrification processes. The expression levels of the denitrifying functional genes nirS and nosZ were decreased and N2O release was stimulated due to the presence of SMX and/or EHMC in the sediments. To the best of our knowledge, this study is the first to report the effects of EHMC and its mixtures on the dissimilatory nitrate reduction processes and N2O releases in river sediments. Our results indicated that the widespread occurrence of emerging pollutants in high-altitude rivers may disturb the nitrogen transformation processes and increase the pressure of global warming.

Biogeochemical sulfur cycling coupling with dissimilatory nitrate reduction processes in freshwater sediments

2018 ◽  
Vol 26 (2) ◽  
pp. 121-132 ◽  
Author(s):  
Jin Zhu ◽  
Yan He ◽  
Yishuang Zhu ◽  
Minsheng Huang ◽  
Yaping Zhang
Keyword(s):  
Nitrate Reduction ◽  
Freshwater Ecosystems ◽  
N Cycling ◽  
Ammonium Oxidation ◽  
Freshwater Sediments ◽  
Reduction Processes ◽  
Dissimilatory Nitrate Reduction ◽  
Functional Bacteria ◽  
S Cycling ◽  
Genes Encoding

Dissimilatory nitrate reduction processes including denitrification, anaerobic ammonium oxidation (ANAMMOX), and dissimilatory nitrate reduction to ammonium (DNRA) are crucial nitrogen (N) cycling pathways in freshwater ecosystems. Denitrification has long been considered as the primary pathway of N loss from aquatic environments. Recently, ANAMMOX and DNRA have been gaining more attention in N dynamics at the sediment–water interface. The ubiquitous presence of various sulfur (S) species in sediments makes them an important role on N transport. Interactions between dissimilatory nitrate reduction and the S cycle are mainly embodied by the inhibitory or promoting effects of sulfide on nitrate-reducing pathways, as well as the competition of sulfate with nitrate reduction for substrates. This review summarizes the current progress in the coupling of S cycling with nitrate-reducing pathways in freshwater sediments, the distribution and diversity of related microorganisms, as well as the functional genes encoding related enzymes. Future perspectives of related research are discussed in terms of coupled N cycling with other element cycles and molecular detection of functional bacteria to better understand and manipulate N cycling in freshwater environments.

Variations of dissimilatory nitrate reduction processes along reclamation chronosequences in Chongming Island, China

2021 ◽  
Vol 206 ◽  
pp. 104815
Author(s):  
Yinghui Jiang ◽  
Guoyu Yin ◽  
Lijun Hou ◽  
Min Liu ◽  
Dengzhou Gao ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Chongming Island ◽  
Reduction Processes ◽  
Dissimilatory Nitrate Reduction

scholarly journals Denitrification, anaerobic ammonium oxidation, and dissimilatory nitrate reduction to ammonium in an East African Great Lake (Lake Kivu)

2017 ◽  
Vol 63 (2) ◽  
pp. 687-701 ◽  
Author(s):  
Fleur A. E. Roland ◽  
François Darchambeau ◽  
Alberto V. Borges ◽  
Cédric Morana ◽  
Loreto De Brabandere ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Great Lake ◽  
Anaerobic Ammonium Oxidation ◽  
Ammonium Oxidation ◽  
East African ◽  
Dissimilatory Nitrate Reduction ◽  
Lake Kivu

The synergetic and competitive mechanism and its dominant affecting factors of dissimilatory nitrate reduction processes: a review

2016 ◽  
Vol 36 (5) ◽  
Author(s):  
杨杉 YANG Shan ◽  
吴胜军 WU Shengjun ◽  
蔡延江 CAI Yanjiang ◽  
周文佐 ZHOU Wenzuo ◽  
朱同彬 ZHU Tongbin ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Affecting Factors ◽  
Reduction Processes ◽  
Dissimilatory Nitrate Reduction ◽  
Competitive Mechanism

scholarly journals Anaerobic ammonium oxidation, denitrification and dissimilatory nitrate reduction to ammonium in the East China Sea sediment

2013 ◽  
Vol 10 (3) ◽  
pp. 4671-4710 ◽  
Author(s):  
G. D. Song ◽  
S. M. Liu ◽  
H. Marchant ◽  
M. M. M. Kuypers ◽  
G. Lavik
Keyword(s):  
East China Sea ◽  
Nitrate Reduction ◽  
Nitrogen Transformation ◽  
Outer Shelf ◽  
East China ◽  
The East China Sea ◽  
N Loss ◽  
High Background ◽  
China Sea ◽  
Dissimilatory Nitrate Reduction

Abstract. Benthic nitrogen transformation pathways were investigated in the sediment of the East China Sea in June of 2010 using the 15N isotope pairing technique. Slurry incubations indicated that denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) as well as nitrate release by nitrate storing organisms occurred in the East China Sea sediments. These four processes did not exist independently, the nitrate release therefore diluted the 15N labeling fraction of NO3−, a part of the 15NH4+ derived from DNRA also formed 30N2 via anammox. Therefore current methods of rate calculations led to over and underestimations of anammox and denitrification respectively. Following the procedure outlined in Thampdrup and Dalsgaard (2002), denitrification rates were slightly underestimated by on average 6% without regard to the effect of nitrate release, while this underestimation could be counteracted by the presence of DNRA. On the contrary, anammox rates calculated from 15NO3− experiment were significantly overestimated by 42% without considering nitrate release. In our study this overestimation could only be compensated 14% by taking DNRA into consideration. In a parallel experiment amended with 15NH4+ + 14NO3−, anammox rates were not significantly influenced by DNRA due to the high background of 15NH4+ addition. Excluding measurements in which bioirrigation was present, integrated denitrification rates decreased from 10 to 4 mmol N m−2 d−1 with water depth, while integrated anammox rates increased from 1.5 to 4.0 mmol N m−2 d−1. Consequently, the relative contribution of anammox to the total N-loss increased from 13% at the shallowest site near the Changjiang estuary to 50% at the deepest site on the outer shelf. This study represents the first time in which anammox has been demonstrated to play a significant role in benthic nitrogen cycling in the East China Sea sediment, especially on the outer shelf. N-loss as N2 was the main pathway, while DNRA was also an important pathway accounting for 20–31% of benthic nitrogen transformation in the East China Sea. Our study demonstrates the complicated interactions among different benthic nitrogen transformations and the importance of considering denitrification, DNRA, anammox and nitrate release together when designing and interpreting future studies.

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