Human pressure is reshaping coral reefs at the chemical level, according to a new study led by the University of Hawai‘i at Mānoa and published in Nature Communications. Researchers report that a suite of 25 contaminants—sourced from agriculture, industry, and pharmaceuticals—accumulates in the soft tissues of corals near Maui, Hawai‘i. Alongside this chemical intrusion, the same coastal sites show a measurable decline in the coral’s internal nutrient and energy reserves. The result is a lower capacity to withstand environmental stressors such as heat and ocean acidification.
To uncover these hidden changes, the team used coral metabolomics, effectively reading the “metabolome” stored inside coral tissues. Lead author Zachary Quinlan, a researcher at the Hawai‘i Institute of Marine Biology, says metabolome monitoring could become a practical way to track anthropogenic damage before it is visible in traditional reef metrics.
The study analyzed metabolomes from 380 lobe corals (Porites lobata) and rice corals (Montipora capitata) across 16 locations off west and south Maui. Importantly, the researchers compared sites with different degrees of human influence, spanning both impacts originating from land-based watersheds and changes occurring within the marine ecosystem itself.
Across species, human activity altered the metabolic composition of coral tissues. In more disturbed areas, contaminants increased while nitrogen and energy-related compounds decreased, indicating that corals may be reallocating internal resources under chronic chemical and environmental pressure.
Quinlan highlights a striking pattern: despite the two coral species having distinct life strategies, both showed nearly identical metabolome trends. The consistency suggests that anthropogenic forcing may be strong enough to impose similar physiological signatures across different coral types.
The team also connected current chemistry to reef history. Using coral-cover trends from five sampling sites following the severe 2016 bleaching event, they found that locations with the greatest post-bleaching declines exhibited the most impacted metabolomes. There, nitrogen and energy reserves were reduced, while stress-associated chemicals were enriched.
Two mechanisms were proposed. First, accumulated anthropogenic molecules—including pharmaceuticals and industrial byproducts—may directly stress coral physiology. Second, increased human-driven environmental demands could force corals to spend nitrogen and energetic resources that would otherwise support recovery after heat and carbonate chemistry stress.
Overall, the findings position coral metabolomes as a sensitive diagnostic for ecosystem disturbance and contaminant escape into coastal environments. The study underscores the urgency of reducing human impacts to protect both marine resilience and human health, and it points toward controlled experiments aimed at boosting coral nitrogen and energy reserves.
Subject of Research: Coral metabolome changes and contaminant loads in relation to human land use
Article Title: Coral metabolome quality and contaminant loads track human land use
News Publication Date: 15-Jul-2026
Web References: https://www.nature.com/articles/s41467-026-74960-7
References: 10.1038/s41467-026-74960-7
Image Credits: UH Mānoa/ SOEST/ HIMB
Keywords: coral metabolomics, contaminants, pharmaceuticals, nutrient depletion, reef resilience, anthropogenic disturbance, metabolome tracking, bleaching aftermath, Maui, Porites lobata, Montipora capitata
