Southern Ocean: 3-dimensional depth sections of nitrate δ15N (left; ‰), nitrate δ18O (middle; ‰) and nitrate δ15N minus nitrate δ18O (right; ‰) from large scale sections across the Southern Ocean (P06, P18, I08S and VOY03; nitrate δ15N data at 40°S in the South Atlantic are from a transect conducted by the UK GEOTRACES).
Ocean nitrate isotopes: a global compilation