Fig. 9. Annual cycle of surface silicate (SiO₃) concentrations (mmol m^-3) in the Labrador Sea (partitioned into shelves and central basin): vertical bars = climatology (Garcia et al., 2006), points = average values from LSMP spring and summer missions (vertical lines = standard errors, SE). Dashed line = SiO₃-limitation threshold parameter (N_t).