Fig. 4

Model-derived vertical N/P ratios (a, b) and Si/N ratios (c, d) in decay eddy and mature eddy by assuming a diatom uptake N/P ratio of 16 (orange line) and 10 (blue line) and Si/N ratio of 2 (blue line) and 1 (green line), respectively. Here, the uptake N/P ratios for non-diatoms are arbitrarily set as 16. The green dots are the in situ N/P and Si/N ratios in both C1 and C2 cores; the black line shows the N/P and Si/N profiles controlled only by physical upwelling and mixing