Grain size tunes microbial community assembly and nitrogen transformation activity under frequent hyporheic exchange: A column experiment
Grain size tunes microbial community assembly and nitrogen transformation activity under frequent hyporheic exchange: A column experiment
复制标题
频繁潜流交换下颗粒尺寸调节微生物群落组装和氮转化活性：柱实验
DOI：
10.1016/j.watres.2020.116040
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发表时间：
2020
期刊：
影响因子：
12.8
通讯作者：
Lihua Niu
中科院分区：
文献类型：
--
作者：
Yi Li;Jinxin Zhu;Longfei Wang;Yu Gao;Wenlong Zhang;Huanjun Zhang;Lihua Niu
Hyporheic zones (HZ) are hotspots for biogeochemical reactions where groundwater and surface water mix. River dam buildings and other hydrologic controls alter the sediment grain size distribution and modify the downstream hyporheic exchange, with cascading effects on geochemical and microbial processes in river corridors. In this lab-scale column experiment, the N transformations in HZ filled with sediments in different grain sizes were investigated with a focus on understanding the interplay among variational hydraulic connectivity, microbial community structure, functional potential under frequent groundwater−surface water exchange. Porosity was identified as the main driver determining bacterial community assembly in HZ sediments. Significant microbial zonation was observed along the columns and the degree of co-occurrence of bacterial communities in the Fine column was lower than that in the Coarse and Mix columns. The Coarse column allowed for almost 2.47 times the exchange flux relative to the Fine column, and generates the fastest DO consumption rate (−6.52 μg O2/L·s). The enrichment of nitrifiers, i.e.,CytophagaceaeandBacillaceaeand nitrification functional genes, i.e.,amoA_AOA andamoA_AOB revealed the higher nitrification potential in column filled with coarse sediments. In comparison, the highest NH4+production rates (2.4 × 10−3μg N/L·s) took place in Fine column. The higher abundancies of denitrifiers such asComamonadaceaeandLysobacterand enrichment of functional genes ofnirKandnirSinterestingly suggested the elevated denitrification potential in Fine column in a more anaerobic environment. The results implied that variations in microbial functional potential and associated nitrogen transformation may occur in size-fractioned HZ to dynamic hyporheic exchange, which added new knowledge to the underlying biogeochemical and ecological processes in regulated river corridors.
