Theory 60/Carbon cycle/Termination phase
Sink Saturates on a Ratio
The claim
A carbon sink stops growing when the ratio of fertilisation benefit to nutrient limitation falls to one, so nitrogen supply caps the response.
01Mechanism
Extra CO2 helps only while another resource is not limiting; the ratio sets the cap.
02Prediction
Saturation should track the ratio.
03Refutation
Saturation tracking atmospheric CO2 would remove nutrients.