What is "f-ratio"

In oceanic biogeochemistry, the f-ratio is the fraction of total primary production fuelled by nitrate (as opposed to that fuelled by other nitrogen compounds such as ammonium). This fraction is significant because it is assumed to be directly related to the sinking (export) flux of organic marine snow from the surface ocean by the biological pump. The ratio was originally defined by Richard Eppley and Bruce Peterson in one of the first papers estimating global oceanic production.

F-ratio or f-ratio may refer to:

• f-number, f-ratio, or focal ratio, the ratio of the focal length of an optical system to the diameter of its entrance pupil
• f-ratio, in oceanography, which relates recycled and total primary production in the surface ocean
• The F-ratio used in statistics, which relates the variances of independent samples; see F-distribution