Abstract A long‐standing hypothesis postulates that the elevated productivity at continental shelf break regions is stimulated by enhanced nutrient supply to the surface sunlit depths, however, direct, quantitative evidence has been lacking. We tested this hypothesis with a set of high‐resolution physical and biogeochemical observations from repeated summertime surveys across the Northeast U.S. continental shelf break front. We found direct evidence during summer at this shelf break frontal region that: (a) near‐bottom flow convergence, a necessary process leading to frontal upwelling, was a common occurrence, happening over 75% of the time; (b) nitrate concentrations were elevated, characterized by a dome‐shaped cross‐shelf distribution approximately 30 m tall, extending from the foot of the shelf break front up to the base of the euphotic layer; (c) subsurface chlorophyll enhancement was a persistent feature. Together, these findings link bottom flow convergence, nutrient upwelling, and phytoplankton enhancement, elucidating the shelf break frontal upwelling dynamics.

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