Fig. 1: Coral core and water sample locations in the wider Caribbean region.
From: Equatorial upwelling of phosphorus drives Atlantic N2 fixation and Sargassum blooms
a,The coral core locations are indicated by large triangles with black outlines, and water samples are denoted by large circles with black outlines. The small circles correspond to previous measurements taken from ref. 40. The colour scale for all symbols shows the nitrate δ15N (expressed in ‰ with respect to air) at 200 m depth. Coral core sample locations are Hog Reef, Bermuda (Bm: 32.4469° N, 64.8252° W), Cayo Santa María, Cuba (Cu: 22.6677° N, 79.0997° W), Puerto Morelos National Marine Park, Mexico (Mx: 20.8900° N, 86.8100° W), Turneffe Atoll, Belize (Bz: 17.4027° N, 87.8905° W), Caye d’Olbian, Martinique (Mq: 14.4669° N, 61.0164° W), Little Tobago Island, Trinidad and Tobago (Tb: 11.2986° N, 60.5083° W) and Cahuita, Costa Rica (Cr: 9.7514° N, 82.8192° W). b, Water-column excess P (in µM; expressed as P*, which equals PO43− − NO3−/16) at 200 m depth, based on the GLODAPv2.2022 dataset76. Newly measured nitrate δ15N and P* values from an east–west transect at 13° N were obtained on the sailing yacht Eugen Seibold during the expedition of December–March 2022/2023, and data from north–south transects were obtained on the GO-SHIP A20 (16 March to 16 April 2021) and A22 (20 April to 16 May 2021) sections. New data are indicated as large circles with black outlines, and these are plotted on the same scale as the global dataset. Both panels include the prevailing surface currents (black arrows) and the extent of the GASB (brown shaded area). Basemaps created with Ocean Data View v.5.6.3 (https://odv.awi.de).
