Assessing multi-trophic aquatic community responses to reclaimed water discharge in an arid urban river system

IF 4.4 3区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Journal of contaminant hydrology Pub Date : 2026-03-01 Epub Date: 2026-02-23 DOI:10.1016/j.jconhyd.2026.104901

Chi Ma , Wenchao Sun , Yi Zhu , Jingshan Yu , Guoqiang Wang , Qimeng Yue , Zhiwen Yi , Hu Xu , Jianping Jia

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引用次数: 0

Abstract

Reclaimed water replenishment plays a crucial role in sustaining urban river systems in arid regions where natural water resources are scarce. However, its ecological impacts, particularly on microbial community diversity and structure, remain insufficiently understood, with significant knowledge gaps regarding how reclaimed water replenishment influences these dynamics. Here, we quantified changes in water quality and multi-trophic community structure along natural (NR), reclaimed (RR), and mixed (NRR) sections of the Xiaohei River, an arid urban river in northern China. The results indicate that reclaimed water discharge altered the physicochemical conditions of the river systems, particularly in terms of nutrient enrichment, with total nitrogen and total phosphorus concentrations increasing on average by 67% and 84%, respectively. After reclaimed water replenishment, significant shifts in community composition and diversity were observed, with the mean richness of algae and metazoans increasing by 20.2% and 29.7%, respectively, while that of bacteria and protozoa decreased by 19.6% and 4.1%. Nitrogen and phosphorus nutrients, together with hydrodynamic conditions, emerged as the primary drivers of biodiversity variation, with particularly strong associations observed for bacterial, algal, and protozoan communities. Chlorophyta and Rotifera displayed contrasting responses to reclaimed water replenishment, with Chlorophyta exhibiting a monotonic linear response and Rotifera showing a nonlinear (hump-shaped) relationship with physicochemical gradients, underscoring differential responses across trophic levels. This study improves understanding about the ecological effects of reclaimed water replenishment on aquatic ecosystems. It provides a scientific basis for nutrient control and ecological monitoring to support coordinated water allocation and ecological conservation in arid urban river systems.

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干旱城市河流系统中水排放对多营养水生群落的影响

在自然水资源匮乏的干旱地区，再生水补给在维持城市河流系统中起着至关重要的作用。然而，其生态影响，特别是对微生物群落多样性和结构的影响，仍未得到充分了解，在再生水补给如何影响这些动态方面存在重大知识空白。在此，我们量化了中国北方干旱城市河流小黑河的自然（NR）、填海（RR）和混合（NRR）河段水质和多营养群落结构的变化。结果表明，中水排放改变了河流水系的理化条件，特别是营养物的富集，总氮和总磷浓度平均分别增加了67%和84%。补充中水后，群落组成和多样性发生了显著变化，藻类和后生动物的平均丰富度分别增加了20.2%和29.7%，细菌和原生动物的平均丰富度分别下降了19.6%和4.1%。氮和磷营养物，连同水动力条件，成为生物多样性变化的主要驱动因素，在细菌、藻类和原生动物群落中观察到特别强烈的关联。绿藻和轮尾草对再生水补给的响应表现出明显的差异，绿藻对再生水补给的响应呈单调线性关系，轮尾草对再生水补给的响应呈非线性（驼峰状）关系，显示出不同营养水平的差异响应。本研究提高了对再生水补给对水生生态系统生态效应的认识。为干旱区城市水系养分调控和生态监测提供科学依据，为协调水资源配置和生态涵养提供支持。

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来源期刊

Journal of contaminant hydrology 环境科学-地球科学综合

CiteScore

6.80

自引率

2.80%

发文量

129

审稿时长

68 days

期刊介绍： The Journal of Contaminant Hydrology is an international journal publishing scientific articles pertaining to the contamination of subsurface water resources. Emphasis is placed on investigations of the physical, chemical, and biological processes influencing the behavior and fate of organic and inorganic contaminants in the unsaturated (vadose) and saturated (groundwater) zones, as well as at groundwater-surface water interfaces. The ecological impacts of contaminants transported both from and to aquifers are of interest. Articles on contamination of surface water only, without a link to groundwater, are out of the scope. Broad latitude is allowed in identifying contaminants of interest, and include legacy and emerging pollutants, nutrients, nanoparticles, pathogenic microorganisms (e.g., bacteria, viruses, protozoa), microplastics, and various constituents associated with energy production (e.g., methane, carbon dioxide, hydrogen sulfide). The journal''s scope embraces a wide range of topics including: experimental investigations of contaminant sorption, diffusion, transformation, volatilization and transport in the surface and subsurface; characterization of soil and aquifer properties only as they influence contaminant behavior; development and testing of mathematical models of contaminant behaviour; innovative techniques for restoration of contaminated sites; development of new tools or techniques for monitoring the extent of soil and groundwater contamination; transformation of contaminants in the hyporheic zone; effects of contaminants traversing the hyporheic zone on surface water and groundwater ecosystems; subsurface carbon sequestration and/or turnover; and migration of fluids associated with energy production into groundwater.