Residence Times (t)

Residence time: The amount of time (in years) required to replace a given ocean constituent by river supply.

Residence times are important because they tell you how quickly or slowly an ocean constituent can respond to a change in the constituent supply or removal rates.

Needed for calculation

Amount of constituent in ocean (reservoir):

Amount of constituent coming in by rivers annually (flux):

Example 1: Residence time of Columbia University undergrads

Reservoir of CU undergrads: 4000 students
Incoming first-year students, per year: 1000

Residence time of CU undergrads:

4000 total students / 1000 incoming each year = 4 years