There are two nutrients incorporated into the model: dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphates (DIP). Both follow the same model structure, but vary in parameter values.
Nutrients are gained through mineralization of detritus and diffusion from the sediments into the water column. Nutrients are lost through primary production uptake and diffusion from the water column to the sediments. Spatial exchange is determined mainly by the speed of the currents. The ratio of surface water volume moving in a certain direction to the total water volume determines the fraction of nutrients that will move in the same direction.
* Note: only spatial movement to the north is portrayed here for the sake of simplicity. Movement to the south, east, and west is calculated in the same manner.