Invasive Spartina alterniflora accelerates the increase in microbial nitrogen fixation over nitrogen removal in coastal wetlands of China

• DOI: 10.1016/j.eehl.2023.07.007
• Publication Date: 2023-07-28T23:07:08Z
• Authors: Shuntao Chen; Dengzhou Gao; Xiaofei Li; Yuhui Niu; Cheng Liu; Dongyao Sun; Yanling Zheng; Hongpo Dong; Xia Liang; Guoyu Yin; Xianbiao Lin; Min Liu; Lijun Hou
• Keywords: Spartina alterniflora; Phragmites; Salt marsh; Biogeochemical Cycle; Nitrogen Cycle

Saltmarsh plants play a vital role in mediating nitrogen (N) biogeochemical cycle estuarine and coastal ecosystems. However, the effects of invasive Spartina alterniflora on N fixation removal, as well how these two processes balance to determine budget, remain unclear. Here, simultaneous quantifications removal via 15N tracing experiment with native Phragmites australis, S. alterniflora, bare flats corresponding functional gene abundance by qPCR were carried out explore response dynamics invasion. Our results showed that rates ranged from 0.77 ± 0.08 16.12 1.13 nmol/(g·h) 1.42 0.14 16.35 1.10 nmol/(g·h), respectively, generally facilitated rates. Based difference between rates, net N2 fluxes estimated range –0.39 8.24 2.23 nmol/(g·h). Estimated stands lower than those P. australis stands, indicating increase caused invasion may be more offset process. Random forest analysis revealed microorganisms most important factor associated transformation Overall, our highlight importance evaluating budget wetlands, providing valuable insights into ecological effect