The f-ratio

In oligotrophic areas of the oceans there is little upward movement of water from below the euphotic zone and thus the amount of new nitrogen is relatively small. In upwelling regions, however, the amount of new nitrogen is very large. The ratio of new production to total (new + regenerated) production is referred to as the f-ratio. This number is probably 0.1 or less in oligotrophic waters, but as high as 0.8 in upwelling zones. Annual average for the whole ocean is between 0.3-0.5.