LAUSR

Seabirds drastically transform the environmental conditions of the sites where they establish their breeding colonies via soil, sediment, and water eutrophication (hereafter termed ornitheutrophication). Here, we report worldwide amounts of total nitrogen (N) and total phosphorus (P) excreted by seabirds using an inventory of global seabird populations applied to a bioenergetics model. We estimate these fluxes to be 591 Gg N y−1 and 99 Gg P y−1, respectively, with the Antarctic and Southern coasts receiving the highest N and P inputs. We show that these inputs are of similar magnitude to others considered in global N and P cycles, with concentrations per unit of surface area in seabird colonies among the highest measured on the Earth’s surface. Finally, an important fraction of the total excreted N (72.5 Gg y−1) and P (21.8 Gg y−1) can be readily solubilized, increasing their short-term bioavailability in continental and coastal waters located near the seabird colonies.The global impact of seabird populations on nutrient cycles is poorly understood. Here, the authors use a bioenergetic model and a global seabird population inventory to estimate the amounts of nitrogen and phosphorus excreted by seabirds and estimate them to be 591 Gg N y−1 and 99 Gg P y−1 respectively.