Nitrogen accumulation and attenuation in the Ganges-Brahmaputra-Meghna river system: An evaluation with multiple stable isotopes and microbiota

作者：Jiang, Shan^*; Hossain, Md. Jaker; Uddin, Sheikh Aftab; Ye, Qi; Wu, Ying; Jin, Jie; Su, Han; Liu, Zheng Bo; He, Lijun; Zhang, Jing

来源：Marine Pollution Bulletin, 2023, 193: 115204.

DOI：10.1016/j.marpolbul.2023.115204

• Nitrogen
• Stable isotopes
• Microbiota
• Ganges-Brahmaputra-Meghna
• Major ions

We examined dissolved inorganic nitrogen (DIN) accumulation and attenuation in the lower stream and estuary of the Ganges-Brahmaputra-Meghna River system. In the lower stream of Ganges, Meghna and Brahmaputra rivers, nitrate (NO3  ) was the dominant component in the DIN pool apart from the site near an industrial center. Concentrations of NO3  displayed minor differences between surface and bottom water, accounting for >90 % of the riverine DIN pool. Sources of NO3  were likely to be municipal wastewater and fertilizer based on signals of 15N-NO3  and 18O-NO3  . In the Meghna River, ammonium concentration in river water increased due to sewage discharge from local industrial centers. In the estuary, likely due to the high-abundance nitrifiers, nitrification rates overwhelmed removal rates and led to NO3  accumulation. Towards coastal ocean, DIN concentrations decreased due to seawater dilution and biological assimilation, indicating a tight linkage between the riverine input and ecological stability in the receiving water.

• 单位
  上海交通大学