Fig. 2
From: Seabird colonies as important global drivers in the nitrogen and phosphorus cycles

Global distribution of N and P excretion by seabird colonies. To show the colony distributions in a clear way, a fishnet grid of square cells with 500 km sides and the sum of the number of seabirds included in each cell was generated. Lines delineate regional boundaries after Riddick et al.18: 1. Africa, 2. Antarctica and Southern Ocean, 3. Asia, 4. Atlantic, 5. Australasia, 6. Caribbean and Central America, 7. Europe, 8. Greenland and Svalbard, 9. Indian Ocean, 10. Middle East, 11. North America, 12. Pacific and 13. South America. Scale shows fluxes in Mg y−1, where 1 Mg = 1 × 106 g