The ranking and spatial arrangement of stations is compared according to increasing ΔDIN (mmol N m^-2, as listed in Table 1). The increase in ΔDIN over station rank is linear (R² = 0.98), with small breaks in slope near 250 and 550 mmol N m⁻². One possible grouping of stations, therefore, is: 1) early bloom stations (light green) indicated by ΔDIN < 250 mmol N m⁻²; 2) mid-bloom stations (medium green) indicated by 250 < ΔDIN < 550 mmol N m⁻², and 3) high bloom stations (dark green) indicated by ΔDIN > 550 mmol N m⁻². Geographic map shows that light green stations (early bloom) are located in the northern and western regions of the study area (68 is off the map, see Figure 1), medium green stations (mid-bloom) tend towards the northeast, dark green stations (high bloom) are central and southern. The white lines indicate the edge of the open water (see Mu et al., 2014) on 19 November 2010 (dotted) and 2 January 2011 (dashed), showing how the northern stations experienced fewer ice-free days.