Xuebing Chen , Yuye Shen , Yihong Liu , Fangfang Zhang , Linlin Tian , Jing Wang , Yanjiang Cai , Yan Li , Scott X. Chang
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引用次数: 0
Abstract
Waters in urban landscape are susceptible to nitrogen (N) pollution, potentially leading to supersaturation of dissolved nitrous oxide (N2O) and making them a source of atmospheric N2O. However, the spatiotemporal variations and driving factors of dissolved N2O concentrations in these waters remain unclear. This study examined the spatiotemporal variations of dissolved N2O in an interconnected river-lake system in a subtropical urban landscape. The annual mean dissolved N2O concentration was 0.81 μg N L−1, with a mean N2O saturation of 304 %, indicating the system could act as a N2O emitter. Under the influence of daily fluctuations in water temperature and DO, the diurnal variation of N2O was most pronounced in autumn, with the smallest amplitude observed in winter. Seasonal mean concentrations of dissolved N2O, N, phosphorus (P), chlorophyll-a (Chl-a) and dissolved oxygen (DO) peaked in winter and were lowest in summer. The central lake had significantly lower dissolved N2O, N and P concentrations, but possessed higher water temperature, pH, concentrations of Chl-a and DO than its upstream and downstream rivers. Dissolved N2O concentrations were positively correlated with concentrations of N and P, but negatively with pH, Chl-a, and DO. There was intensifying competition for N between the N2O producers and algae, particularly in summer or in the central lake area. Therefore, the spatiotemporal variations of dissolved N2O concentrations were primarily driven by the integrated effects of seasonal conditions, nutrient fluctuations and algal growth. This research can provide essential scientific guidance for developing the effective strategies to control N pollution and mitigate the risk of N2O emissions from water bodies in urban landscape.
城市景观中的水体容易受到氮(N)污染，可能导致溶解的一氧化二氮（N2O）过饱和，并使其成为大气中N2O的来源。然而，这些水体中溶解N2O浓度的时空变化及其驱动因素尚不清楚。研究了亚热带城市景观中河流-湖泊系统中溶解N2O的时空变化特征。年平均溶解N2O浓度为0.81 μg N L-1，平均N2O饱和度为304%，表明该体系具有N2O排放源的作用。受水温和DO的日变化影响，N2O的日变化在秋季最为明显，在冬季幅度最小。季节平均溶解N2O、N、P、叶绿素a和溶解氧浓度冬季最高，夏季最低。中心湖溶解态N2O、N和P浓度显著低于上游和下游河流，但水温、pH、Chl-a和DO浓度高于上游和下游河流。溶解N2O浓度与N、P浓度呈正相关，与pH、Chl-a、DO呈负相关。N2O生产者与藻类之间对N的竞争加剧，特别是在夏季或湖心区。因此，溶解N2O浓度的时空变化主要受季节条件、养分波动和藻类生长的综合影响。该研究可为制定有效的城市景观水体氮污染控制策略和降低N2O排放风险提供重要的科学指导。
期刊介绍：
Environmental Pollution is an international peer-reviewed journal that publishes high-quality research papers and review articles covering all aspects of environmental pollution and its impacts on ecosystems and human health.
Subject areas include, but are not limited to:
• Sources and occurrences of pollutants that are clearly defined and measured in environmental compartments, food and food-related items, and human bodies;
• Interlinks between contaminant exposure and biological, ecological, and human health effects, including those of climate change;
• Contaminants of emerging concerns (including but not limited to antibiotic resistant microorganisms or genes, microplastics/nanoplastics, electronic wastes, light, and noise) and/or their biological, ecological, or human health effects;
• Laboratory and field studies on the remediation/mitigation of environmental pollution via new techniques and with clear links to biological, ecological, or human health effects;
• Modeling of pollution processes, patterns, or trends that is of clear environmental and/or human health interest;
• New techniques that measure and examine environmental occurrences, transport, behavior, and effects of pollutants within the environment or the laboratory, provided that they can be clearly used to address problems within regional or global environmental compartments.
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