Streams play a significant role in global biogeochemical cycles and are usually sources of greenhouse gasses to the atmosphere. To better understand controls on greenhouse gas production from stream sediments and their contribution to whole stream greenhouse gas evasion, we estimated fluxes of CO₂, CH₄, and N₂O from 48 streams in southern Ontario, Canada that represented a gradient in both the amount and composition of dissolved organic carbon in addition to dissolved nutrients. Greenhouse gas fluxes from oxic sediment incubations were far lower than the fluxes estimated from water column greenhouse gas concentrations at the whole stream scale. Moreover, variation in sediment greenhouse gas fluxes was not positively associated with variation in those estimated from the whole stream or with water column greenhouse gas concentrations. However, dissolved organic carbon and nutrient concentrations were associated with increased sediment CO₂ and N₂O fluxes but consistent variation in dissolved organic matter composition did not appear to regulate these fluxes. Sediment physicochemical properties were unable to explain any variation in sediment CH₄ fluxes. Although whole stream greenhouse gas fluxes integrate heterogeneity in biogeochemical processes within streams, our findings suggest that changes to streams and/or their watersheds resulting in the overall enrichment of nutrients and carbon (e.g., land use change) will increase the production of CO₂ and N₂O from sediments.

溪流在全球生物地球化学循环中发挥着重要作用，通常是大气中温室气体的来源。为了更好地了解河流沉积物对温室气体产生的控制及其对整个河流温室气体逃逸的贡献，我们估计了 CO ₂、CH ₄和 N _2的通量O 来自加拿大安大略省南部的 48 条溪流，除了溶解的营养物质外，它们代表了溶解有机碳的数量和组成的梯度。来自含氧沉积物孵化的温室气体通量远低于从整个河流规模的水柱温室气体浓度估计的通量。此外，沉积物温室气体通量的变化与从整个河流或水柱温室气体浓度估计的变化没有正相关关系。然而，溶解的有机碳和养分浓度与沉积物 CO ₂和 N _{2的增加有关}O 通量但溶解有机物组成的一致变化似乎并未调节这些通量。沉积物理化性质无法解释沉积物CH ₄通量的任何变化。尽管整个溪流温室气体通量整合了溪流内生物地球化学过程的异质性，但我们的研究结果表明，溪流和/或其流域的变化导致养分和碳的整体富集（例如土地利用变化）将增加 CO ₂的产生和来自沉积物的N ₂ O。