Land–Water Transport and Sources of Nitrogen Pollution Affecting the Structure and Function of Riverine Microbial Communities

Abstract

The characterization of variations in riverine microbiota that stem from contaminant sources and transport modes is important for understanding biogeochemical processes. However, the association between complex anthropogenic nitrogen pollution and bacteria has not been extensively investigated owing to the difficulties faced while determining the distribution of nitrogen contaminants in watersheds. Here, we employed the Soil and Water Assessment Tool alongside microbiological analysis to explore microbial characteristics and their responses to complex nitrogen pollution patterns. Significant variations in microbial communities were observed in sub-basins with distinct land–water pollution transport modes. Point source-dominated areas (PSDAs) exhibited reduced microbial diversity, high number of denitrification groups, and increased nitrogen cycling compared with others. The negative relative deviations (−3.38) between the measured and simulated nitrate concentrations in PSDAs indicated that nitrate removal was more effective in PSDAs. Pollution sources were also closely associated with microbiota. Effluents from concentrated animal feeding operations were the primary factors relating to the microbiota compositions in PSDAs and balanced areas. In nonpoint source-dominated areas, contaminants from septic tanks become the most relevant sources to microbial community structures. Overall, this study expands our knowledge regarding microbial biogeochemistry in catchments and beyond by linking specific nitrogen pollution scenarios to microorganisms.

New Insights into Aggregation Behaviors of the UV-Irradiated Dissolved Biochars (DBioCs) in Aqueous Environments: Effects of Water Chemistries and Variation in the Hamaker Constant

“…After returning to the lab, both of them were filtered through a 0.45 μm membrane, characterized, and then stored at 4 °C. 46 The pH (7.34 ± 0.03 vs 7.75 ± 0.10), TOC (2.26 mg/L vs 3.65 mg/L), and electric conductivity (194.3 ± 0.5 μS/cm vs 391.6 ± 1.0 μS/cm) of the Xiangjiang sample were lower than those of the Taozihu one. They have the same most abundant univalent (Na + ) and divalent (Ca 2+ ) cations and anions (SO 4 2− ) (Table S1).…”

“…Although close in distance, they are typically flowing and enclosed waters, respectively. After returning to the lab, both of them were filtered through a 0.45 μm membrane, characterized, and then stored at 4 °C . The pH (7.34 ± 0.03 vs 7.75 ± 0.10), TOC (2.26 mg/L vs 3.65 mg/L), and electric conductivity (194.3 ± 0.5 μS/cm vs 391.6 ± 1.0 μS/cm) of the Xiangjiang sample were lower than those of the Taozihu one.…”

Investigating Temporal and Spatial Variations of Nutrient and Trace Metal Loading in Utah Lake (Utah, USA)

“…Anthropogenic activities have shown an impact on both hydrological patterns and pollutant discharge within watersheds [6]. Microbes in these nutrient sources potentially alter the biogeochemical processes and lead to N 2 O emissions in waters to the atmosphere, which can, in turn, affect nitrification and denitrification processes [6][7][8]. Furthermore, increasing discharges of excessive fertilizers from farming lands, residential lawns, and effluent discharge gradually led to the eutrophication of Utah Lake.…”

Ecological Restoration Effectively Mitigated pCO2 and CO2 Evasions From Severely Polluted Urban Rivers

“…Previous studies in the urbanized river network of Chongqing and Shanghai metropolitan areas, China, provided clear evidence that extensive pollutants generally strengthen CO 2 emissions from urban rivers (X. Wang et al., 2017; Yu et al., 2017). On the other hand, the discharge of municipal sewage and industrial effluents with high dissolved inorganic carbon (DIC) and alkalinity (J. Wang et al., 2021) and active sewage‐treatment microbes (Hiruy et al., 2022; Zhu et al., 2023) could directly or indirectly elevate CO 2 saturation and evasion (Chanda et al., 2020; Luo et al., 2019; J. Wang et al., 2021; Yu et al., 2017). Previous studies have suggested that watershed urbanization could transform rivers into enhanced heterotrophy systems (Gong et al., 2019; X. Wang et al., 2017).…”

“…Wang et al, 2017;Yu et al, 2017). On the other hand, the discharge of municipal sewage and industrial effluents with high dissolved inorganic carbon (DIC) and alkalinity (J. and active sewage-treatment microbes (Hiruy et al, 2022;Zhu et al, 2023) could directly or indirectly elevate CO 2 saturation and evasion (Chanda et al, 2020;Luo et al, 2019;Yu et al, 2017). Previous studies have suggested that watershed urbanization could transform rivers into enhanced heterotrophy systems (Gong et al, 2019;X.…”