Coral metabolome quality and contaminant loads track human land use

Anthropogenic activities pose a significant risk to vulnerable marine ecosystems like coral reefs, particularly those near human population centers. Despite coral reefs being one of the systems most at risk, the relationship between contaminant exposure and coral health across gradients of ecosystem disturbance remains poorly understood. Our metabolomic analysis of 380 corals from 16 sites spanning an anthropogenic impact gradient reveals that the coral metabolome is predictive of anthropogenic ecosystem disturbance. We found that human activities both within catchments and in the marine ecosystem altered the chemodiversity of coral metabolomes with a direct relationship to historic trends in coral cover: nitrogen reserves and metabolome energetic potential are reduced, while stress metabolites are enriched at more impacted sites. We further identify 25 anthropogenic contaminants from agricultural, cosmetological, industrial, and pharmaceutical sources accumulated in coral metabolomes. Our results suggest that the bioaccumulation of pollutants and compositional changes in the metabolome of corals imposed by anthropogenic activities is correlated with coral benthic cover. Together, our findings suggest a direct relationship between coral health, accumulation of dangerous contaminants within corals, and anthropogenic disturbance that is consistent across species.