题名：Nitrogen removal by eutrophic coastal wetlands accomplished with CH₄ emission reduction

来源：Journal of Cleaner Production

发表年代：2022

作者：Hualei Yang, Xuechu Chen*, Chunsong Zhang, Mingming Zhao, Xinmeng Zhao, Danielle C. Perry, Jianwu Tang**

Abstract：Coastal wetlands play an important role in nitrogen removal and are a vital blue carbon sink. The produced methane (CH₄)  in coastal wetlands has been recently identified as a possible carbon  source for denitrification process, providing a significant contribution  to coastal nitrogen cycling. However, the in-situ correlation between CH₄  emissions and denitrification rate, as well as their coupling mechanism  is still unclear. Here, we investigated the nitrogen removal pattern  throughout a complete tidal cycle, quantified the in-situ linkage  between CH₄ emissions and denitrification rate, and explored  the associated microbial mechanisms in the eutrophic coastal wetland.  The results showed that (1) the removal of nitrogen was driven by the  tidal cycle (marsh flooding and drying), which involved two processes -  physical interception and microbial denitrification; (2) the  denitrification rate was linearly positively correlated to the CH₄  emission (R2 = 0.87, p < 0.0001); (3) nitrite- and nitratedependent  denitrifying anaerobic methane oxidation (DAMO) coexisted in the wetland  sediment, and promoted nitrogen removal by utilizing CH₄ as the carbon source for denitrification. Our findings suggested that CH₄  emission could enhance denitrification via DAMO in the field, and  deepened the understanding of the dynamic nitrogen removal process  within eutrophic coastal wetlands, and further indicated a strong  interaction between coastal carbon and nitrogen cycling.