Injection of carbon from the shelf to offshore beneath the euphotic zone in the California Current

[1] High concentrations of chlorophyll are found in the California Current System over 300 km offshore, far from the productive coastal upwelling region, and between 150 and 250 m, well below the depth to which photosynthetically active solar radiation penetrates. This exceptionally deep chlorophyll feature is formed near the coast and transported offshore in the meandering California Current jet. Chlorophyll is forced downward along sloping density surfaces through conservation of potential vorticity along the meandering jet path. Thus mesoscale physical dynamics serve to inject large amounts of carbon, e.g., 2400 t as reported here, per event from regions of active coastal upwelling into the adjacent deep ocean, a process that must be considered when computing oceanic carbon budgets.