Large rivers provide important ecosystem services to society, yet little is known about patterns and controls of key ecological functions, such as benthic metabolism, in these ecosystems. This study describes patterns of temporal and spatial variation of benthic metabolism (gross primary production (GPP) and community respiration (CR)) in the Saint John River, New Brunswick, Canada; a large, regulated river. Temporal variation and drivers of metabolism were assessed throughout the summer using measurements of dissolved oxygen from benthic chambers in the river’s wadeable margins. Differences in metabolism between channel locations (main and side channel) and patches of cobble and sand substrates were also determined. Rates of GPP and CR varied in accordance with a quadratic function throughout the summer months with peak rates attained in mid-July. Variability in metabolism was associated with light and water temperature. Spatial heterogeneity in metabolism was not observed between channel locations. Differences in metabolism between substrates were dependent upon time of year, as differences were only observed in early summer. Findings of this study suggest benthic metabolism in the margins of the Saint John River is controlled by variations temperature and light availability that vary with climatic patterns in the summer months. Consequently, these findings have implications for management of river health given projected scenarios of climate change.

大河流为社会提供了重要的生态系统服务，但对于这些生态系统中关键生态功能（例如底栖生物代谢）的模式和控制知之甚少。这项研究描述了加拿大新不伦瑞克省圣约翰河底栖代谢的时空变化模式（初级总产值（GPP）和社区呼吸（CR））。一条受监管的大河。整个夏季，通过测量河流宜人边缘底栖腔室中的溶解氧来评估时间变化和新陈代谢的驱动力。还确定了通道位置（主通道和侧通道）与鹅卵石和砂质底物斑块之间新陈代谢的差异。整个夏季，GPP和CR的发生率均根据二次函数变化​​，7月中旬达到峰值。新陈代谢的变化与光照和水温有关。在通道位置之间未观察到代谢的空间异质性。底物之间新陈代谢的差异取决于一年中的时间，因为差异仅在初夏才观察到。这项研究的结果表明，圣约翰河边缘的底栖生物代谢受温度和光的可利用性的控制，而温度和光的可利用性在夏季月份随气候模式而变化。因此，鉴于预期的气候变化情景，这些发现对河流健康的管理具有重要意义。因为只有在初夏才观察到差异。这项研究的结果表明，圣约翰河边缘的底栖生物代谢受温度和光的可利用性的控制，而温度和光的可利用性在夏季月份随气候模式而变化。因此，鉴于预期的气候变化情景，这些发现对河流健康的管理具有重要意义。因为只有在初夏才观察到差异。这项研究的结果表明，圣约翰河边缘的底栖生物代谢受温度和光的可利用性的控制，而温度和光的可利用性在夏季月份随气候模式而变化。因此，鉴于预期的气候变化情景，这些发现对河流健康的管理具有重要意义。