Nitrate supply from deep to near-surface waters of the North Pacific subtropical gyre
Seasonal (spring and summer) depletion of dissolved inorganic carbon occurs in the surface mixed layers of most of the unproductive or oligotrophic regions of the world's oceans. The missing dissolved inorganic carbon is thought to be converted to particulate carbon by photosynthesis, yet there are seemingly insufficient dissolved nutrients present to support the required amount of plant growth.