Vegetated urban streams have sufficient purification ability but high internal nutrient loadings: Microbial communities and nutrient release dynamics

文献类型： 外文期刊

第一作者： Kumwimba, Mathieu Nsenga

作者： Kumwimba, Mathieu Nsenga;Li, Xuyong;Huang, Jinlou;Mihiranga, H. K. M.;Kumwimba, Mathieu Nsenga;Li, Xuyong;Huang, Jinlou;Ajibade, Fidelis Odedishemi;Mihiranga, H. K. M.;Kumwimba, Mathieu Nsenga;Ajibade, Fidelis Odedishemi;Ajibade, Fidelis Odedishemi;Muyembe, Diana Kavidia;Dzakpasu, Mawuli;Li, Xuyong

作者机构：

关键词： Vegetated urban streams; Nitrification; Denitrification; Plant uptake; Nitrogen mass balance approach; Plant decomposition; Nutrient release; 16S rRNA gene

期刊名称：SCIENCE OF THE TOTAL ENVIRONMENT （ 影响因子：9.8； 五年影响因子：9.6 ）

ISSN： 0048-9697

年卷期： 2023 年 863 卷

页码：

收录情况： SCI

摘要： The release of nutrients back into the water column due to macrophyte litter decay could offset the benefits of nutrient removal by hydrophytes within urban streams. However, the influence of this internal nutrient cycling on the overly-ing water quality and bacterial community structure is still an open question. Hence, litter decomposition trials using six hydrophytes, Typha latifolia (TL), Phragmites australis (PAU), Hydrilla verticillata (HV), Oenanthe javanica (OJ), Myriophyllum aquaticum (MA), and Potamogeton crispus (PC), were performed using the litterbag approach to mimic a 150-day plant litter decay in sediment-water systems. Field assessment using simple in/out mass balances and uptake by plant species was carried out to show the potential for phytoremediation and its mechanisms. Results from two years of monitoring (2020-2021) indicated mean total nitrogen (TN) retention efficiencies of 7.2-60.14 % and 9.5-55.6 % for total phosphorus (TP) in the studied vegetated urban streams. Nutrient retention efficiencies showed temporal variations, which depended on seasonal temperature. Mass balance analysis indicated that macrophyte as-similation, sediment adsorption, and microbial transformation accounted for 10.31-41.74 %, 0.84-3.00 %, and 6.92-48.24 % removal of the inlet TN loading, respectively. Hydrophyte detritus decay induced alterations in physi-cochemical parameters while significantly increasing the N and P levels in the overlying water and sediment. Decay rates varied among macrophytes in the order of HV (0.00436 g day-1) > MA (0.00284 g day-1) > PC (0.00251 g day-1) > OJ (0.00135 g day-1) > TL (0.00095 g day-1) > PAU (0.00057 g day-1). 16S rRNA gene sequencing anal-ysis showed an increase in microbial species richness and diversity in the early phase of litter decay. The abundances of denitrification (nirS and nirK) and nitrification (AOA and AOB) genes also increased in the early stage and then de-creased during the decay process. Results of this study conducted in seven urban streams in northern China demon-strate the direct effects of hydrophytes in encouraging nutrient transformation and stream self-purification. Results also demonstrate that macrophyte detritus decay could drive not only the nutrient conversions but also the microbial community structure and activities in sediment-water systems. Consequently, to manage internal sources and conver-sions of nutrients, hydrophytic detritus (e.g., floating/submerged macrophytes) must be suppressed and harvested.

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