What is the nutrient spiraling length

Nutrient spiriling length is how far is how far from it being turnt into ammonium then it is taken up again. The spiraling length s short if there is limitation of the nutrient. It is demand compared to availability. If there is a high production the spiral length is short. Low production long spiral length. SW = uptake lenght how long it travels before it is taken up again. The length in the biota = Sb. Uptake length can be meassured