Theory 17/Coastal upwelling/Threshold lens
Blooms Need Supply Over Grazing
The claim
Upwelling blooms occur above a threshold in the ratio of nutrient supply to grazing pressure, so a well-supplied system can stay green.
01Mechanism
Phytoplankton accumulate only when growth outpaces consumption; the ratio determines whether a bloom forms.
02Prediction
Bloom onset should track the ratio.
03Refutation
Blooms tracking nutrients alone would remove grazing.