Zooplankton communities are important components of aquatic food webs in part because they recycle nutrients and carbon. Lacking a complete understanding of the composition of organic material cycled by zooplankton, the breadth of their biogeochemical and ecological contributions to aquatic ecosystems is uncertain. Here, we show that large-bodied zooplankton communities from three diverse biomes across North America release dissolved organic matter (DOM) that is chemically complex. We applied optical techniques and ultrahigh-resolution mass spectrometry to samples of DOM released by zooplankton in leachate incubations and compared these to the composition of aquatic DOM from ambient environments. The leachates captured the DOM released from zooplankton before exposure to environmental conditions that alter its chemical composition. Surprisingly, leachates from all sites contained substantial quantities of all five major fluorescence peaks representing distinct DOM compositions. When averaged, leachates consistently had low optical absorbance and elevated protein-like fluorescence, relative to lake water. Ultrahigh-resolution characterization showed that leachate DOM contained over 7000 detected molecular formulae (MF), many of which were N- and S- rich, with > 10% MF unique to the leachate and not detected in lake DOM. Together, these results help to define the composition of animal DOM inputs, a widely-overlooked end-member in aquatic DOM studies. Given the chemical breadth of zooplankton-derived DOM, this source may partially explain how N- and S- rich, reduced MF persist in these environments. These findings further underscore the rich chemical diversity of linkages between animals and lower trophic levels.

浮游动物群落是水生食物网的重要组成部分，部分原因是它们回收养分和碳。由于对浮游动物循环的有机物质的组成缺乏完整的了解，它们对水生生态系统的生物地球化学和生态贡献的广度是不确定的。在这里，我们展示了来自北美三个不同生物群落的大型浮游动物群落释放化学复杂的溶解有机物 (DOM)。我们将光学技术和超高分辨率质谱应用于渗滤液孵化中浮游动物释放的 DOM 样本，并将这些样本与周围环境中水生 DOM 的组成进行比较。在暴露于改变其化学成分的环境条件之前，渗滤液捕获了从浮游动物释放的 DOM。出奇，所有地点的渗滤液都含有大量代表不同 DOM 成分的所有五个主要荧光峰。平均而言，相对于湖水，渗滤液始终具有较低的吸光度和较高的类蛋白质荧光。超高分辨率表征表明，渗滤液 DOM 包含超过 7000 个检测到的分子式 (MF)，其中许多富含 N 和 S，其中 > 10% MF 是渗滤液独有的，在湖泊 DOM 中未检测到。总之，这些结果有助于定义动物 DOM 输入的组成，这是水生 DOM 研究中被广泛忽视的最终成员。鉴于浮游动物衍生的 DOM 的化学广度，这个来源可以部分解释富含 N 和 S 的、减少的 MF 如何在这些环境中持续存在。