Salinity-normalized concentrations for dissolved inorganic N in sea ice cores as a function of time. Panels show salinity-normalized concentrations for (a) NO3– (or NO3– + NO2– for samples with no NO2– measurements), (b) NO2–, (c) NH4+, and (d) total dissolved inorganic N. The coarsely red hatched, empty green, and finely blue hatched boxes indicate the concentration ranges in surface (0–0.2 m), interior, and bottom-most 0.1-m layers in sea ice, respectively. In all panels, the concentration range in seawater is indicated by the solid line (the range for ammonium in seawater is too low to be discernible, < 0.4 µmol L–1), and the average solar radiation by the dashed line. The symbols * and ** indicate occasions with less than 30 and 15 data points, respectively, in a depth interval. DOI: https://doi.org/10.1525/elementa.217.f6
