Nitrogen-15 Signals of Anthropogenic Nutrient Loading in Reef Corals

The 15N content of tissue from the coral Porites lobata was enriched, relative to corals from reference sites, at 5 of 7 Indo-Pacific sewage-affected reefs. Enrichment was as high as 3.7‰. The δ13C of sewage-affected corals suggests they maintained a high degree of autotrophic nutrition. 15N-enriched wastewater dissolved inorganic nitrogen (DIN), derived from untreated sewage, is the most likely cause for enrichment in coral tissue 15N, though …