Vertical profiles for bulk N concentrations in sea ice cores. Vertical profiles of bulk N concentrations as a function of normalized ice core depth: (a) dissolved inorganic nitrogen (DIN), (b) dissolved organic nitrogen (DON), (c) particulate nitrogen (PN), and (d) total nitrogen (TN). Median concentrations are indicated by the red dashed-dotted and green dotted lines for spring and summer, respectively. The data have been binned into 10% depth intervals. The interquartile ranges are represented by the corresponding colored envelopes. Seawater TN is indicated by the solid black line (value estimated for Antarctic pack ice in Fripiat et al., 2014a). Insufficient data were available in winter (~ 12 per 10% depth interval, collected mainly in late winter). The symbol * indicates depth intervals with less than 30 data points available. DOI: https://doi.org/10.1525/elementa.217.f5