Figure 2
Bulk δ15N (‰ vs. N2) and bulk δ13C (‰ vs. PDB) signatures of L. bicuspidatus (n = 13), N. vinctus (n = 6), L. capensis (gills and non-gills tissue) (n = 3), and sediments from Stations 14, 48, and GeoB1001-l43 (n = 1). Vertical lines show the δ15N range of nitrate in the sediment-overlying water at the central Namibian shelf (parallel line) (Stations 198 and 252)51 as well as in the upwelled SACW off the Namibian shelf (dotted parallel line)17. In addition, vertical help lines (dashed parallel line) show the estimated δ15N range for ammonium calculated from PON of St. 14, Stn. 48 and Geob 1001-l (Supplementary Table S2). The light blue square (blue filled square) and the light red square (red filled square) have δ15NBulk values of acidified samples which were corrected by subtracting 0.3‰, the difference between acidified and non acidified samples measured in this mollusc group that were both acidified and non acidified (Supplementary Table S3).
