Abstract Non-point source nutrient pollution can cause eutrophication, hypoxic events, and harmful algal blooms in surface waters. Surface water eutrophication is frequently attributed to agricultural runoff, a known source of inorganic and organic nutrients to surface and subsurface waters. Analysis of dissolved organic matter (DOM) using ultrahigh resolution mass spectrometry is an effective tool for characterizing diverse organic nitrogen and phosphorus components of DOM that may be mineralized and/or assimilated and ultimately contribute to eutrophication. An anion exchange resin was applied to extract DOM from surface and subsurface tile runoff from agricultural plots located within the Maumee River watershed (Ohio, USA) that received raw liquid manure, polymer-treated dewatered manure, or no manure (control). DOM extracts were analyzed using Fourier transform ion cyclotron resonance mass spectrometry prior to manure application and during three runoff events after manure application. Organic nitrogen compounds were predominant, making up 38–48% of the total assigned formulas. Principle coordinates analysis indicated clustering predominately by sample month and secondarily by treatment. These findings show that a large amount of variability in DOM in runoff was observed regardless of manure application, indicating the important role played by natural processes in driving transformation of the DOM pool during the growing season. Molecular ions unique to runoff from manure-applied plots were also identified that may be useful in source-tracking of non-point source nutrient pollution in waters draining to Lake Erie.

中文翻译：

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季节性变化在驱动农业径流中溶解有机物变化中占主导地位的肥料施用

摘要 非点源营养物污染可导致地表水富营养化、缺氧事件和有害藻华。地表水富营养化通常归因于农业径流，农业径流是地表水和次地表水的无机和有机营养物质的已知来源。使用超高分辨率质谱法分析溶解有机物 (DOM) 是表征 DOM 中可能被矿化和/或同化并最终导致富营养化的各种有机氮和磷成分的有效工具。使用阴离子交换树脂从位于 Maumee River 流域（美国俄亥俄州）内的农业地块的地表和地下瓷砖径流中提取 DOM，这些地块接受原始液体肥料、聚合物处理的脱水肥料或无肥料（对照）。在施肥之前和施肥后的三个径流事件期间，使用傅立叶变换离子回旋共振质谱法分析 DOM 提取物。有机氮化合物占主导地位，占指定配方总数的 38-48%。原理坐标分析表明聚类主要按样本月份，其次是按治疗。这些发现表明，无论施用何种肥料，都观察到径流中 DOM 的大量变化，表明自然过程在生长季节期间驱动 DOM 池的转变中发挥了重要作用。还确定了施肥地块径流所特有的分子离子，它们可能有助于追踪伊利湖水体中非点源营养物污染的源头。