N Transformation-C Turnover Processes and Microbial Community Structure Responding to Hydrodynamic Mixing of Groundwater and Surface Water in Hyporheic Zone Sediment Columns
Increased dam operations and global climate changes have altered hyporheic flow directions and flux in riverine systems. Nonetheless, the impacts of hydrodynamic mixing of groundwater and surface water on coupled N transformation-C turnover processes, and their relations with microbial community structure appear to be rarely addressed. In this lab-scale experiment, N-transformation and dissolved organic matter (DOM) turnover in hyporheic zone (HZ) column filled with sediments experiencing river water-groundwater mixing were investigated. Upwelling of synthesized groundwater, downwelling of synthesized river water and exchangeable injection of both feed water created distinct microbial zonation and N-transformation processes. The sequencing data and functional gene profiles indicated that mixing of river water and groundwater enhanced microbial diversity and N-transformation functions. N-transformation pathways analysis implied that nitrification, denitrification, and anammox jointly impacted the fate of nitrate when the HZ sediment experienced exchangeable flows, which was more complex than the situation when HZ sediment was only fed with upwelling or downwelling flow. The variation in DOM molecular composition in response to upwelling/downwelling flows were explored, and the correlation between DOM characters and microbial community implied the presence of more abundant metabolic pathways associated with DOM fractions under downwelling flow. Fluorescent components, protein-like and lignin-like fractions in sediment-detached DOM were clustered with microbial communities in one module in downwelling column. The strains of Nitrospinae, Dinghuibacter , and Lentimicrobium etc. were key species collaborating to metabolize both nitrogen and carbon in HZ sediments. The work conducted a multi-faceted approach analyzing the N-transformation and carbon turnover processes responding to hydrodynamic mixing of groundwater and surface water, leading to valuable insights into hyporheic zone functions
Year of publication: |
[2021]
|
---|---|
Authors: | Wang, Longfei ; Wang, Yutao ; Li, Yi ; Zhu, Jinxin ; Zhang, Wenlong ; Zhang, Huanjun ; Niu, Lihua ; Wu, Jun |
Publisher: |
[S.l.] : SSRN |
Saved in:
freely available
Saved in favorites
Similar items by person
-
Xia, Yong, (2018)
-
Wu, Jun, (2018)
-
Habiba, Umm E., (2020)
- More ...