Streams and rivers are key sources of nitrous oxide (N₂O), which is a powerful greenhouse gas. Incomplete denitrification results in N₂O production, which is controlled by nitrate (NO₃⁻-N) and organic carbon (C) availability, as well as water temperature. Yet, few studies have experimentally isolated these drivers, especially in lotic systems. We used sediment core incubations conducted at 15 and 25 °C and membrane inlet mass spectrometry to understand how NO₃⁻-N, C, and temperature influence N₂O production rates and yields (as %) from sediment denitrification. In general, conditions that enhanced denitrification rates also increased N₂O production. At both temperatures, we observed higher N₂O production with added C, which was contrary to previous studies, and rates remained high across the NO₃⁻-N gradient at 25 °C. Thus, as global temperatures warm and organic C availability increases in streams and rivers, N₂O production from incomplete denitrification in alluvial plain riverine sediments will likely increase.

溪流和河流是一氧化二氮 (N ₂ O) 的主要来源，一氧化二氮是一种强大的温室气体。不完全反硝化会导致 N ₂ O 产生，这由硝酸盐 (NO ₃ ⁻ -N) 和有机碳 (C) 可用性以及水温控制。然而，很少有研究通过实验分离出这些驱动因素，尤其是在 Lotic 系统中。我们使用在 15 和 25 °C 下进行的沉积物核心孵化和膜入口质谱分析来了解 NO ₃ ⁻ -N、C 和温度如何影响沉积物反硝化的 N ₂ O 生产率和产量（以 % 表示）。一般来说，提高反硝化率的条件也会增加 N ₂Ø 生产。在这两个温度下，我们观察到添加 C 后 N ₂ O 产量更高，这与之前的研究相反，并且在 25 °C 时，整个 NO ₃ ^{− -N 梯度的速率仍然很高。}因此，随着全球气温变暖和溪流和河流中有机碳利用率的增加，冲积平原河流沉积物中不完全反硝化产生的N _{2 O 产量可能会增加。}