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How human activities compromise coral health and resilience
Human activities are fundamentally altering the chemical makeup of coral reefs, according to a study led by the University of Hawai'i at Mānoa and published in Nature Communications. The research team discovered that 25 contaminants from agricultural, industrial and pharmaceutical sources accumulated in the soft tissues of corals around Maui, Hawai'i. Additionally, in areas affected by human activities, energy and nutrient availability within coral tissue decreases, making corals significantly less resilient to environmental stressors such as warmer or more acidic waters.
"Our findings suggest that monitoring the pool of chemicals within the coral tissues, called metabolomes, can serve as a powerful tool for tracking the hidden impacts of anthropogenic disturbance on marine life," said Zach Quinlan, lead author and research biologist at the Hawai'i Institute of Marine Biology in the UH Mānoa School of Ocean and Earth Science and Technology.
Quinlan and an international team of researchers tested the metabolomes of 380 lobe corals (Porites lobata) and rice corals (Montipora capitata) from 16 sites off west and south Maui.
They found that human activities both within the adjacent watershed and in the marine ecosystem altered the composition of the corals' metabolomes. In areas with greater ecosystem disturbance, contaminants accumulated and nutrient and energy reserves in coral tissues decreased.
"It was extremely surprising that the metabolomes of both coral species had almost identical trends," said Quinlan. "These corals have very different life strategies, and we wouldn't normally expect them to accumulate contaminants or respond similarly to disturbances. This demonstrates how strong a force these anthropogenic activities really are."
Clues from the 2016 bleaching event
Using historical trends in coral cover from five of the sites they sampled, the team found that the sites with the most severe declines in coral cover after the 2016 bleaching event also had the most affected metabolomes. At more affected sites, nitrogen and energy reserves were reduced, while stress chemicals were enriched.
The research team proposed two potential mechanisms by which human activities and contamination of marine environments lead to decreased coral resilience:
- accumulation of anthropogenic molecules such as pharmaceuticals and industrial byproducts
- increased pressure from anthropogenic activities requires corals to use portions of their nitrogen and energy reserves
"This response to anthropogenic pressure makes the coral less resilient to stressors," said Quinlan. "Together, our findings suggest a direct relationship between anthropogenic disturbance, accumulation of dangerous contaminants within corals and coral health that is consistent across species."
Tracing contaminants through the ecosystem
The researchers propose that monitoring the metabolomes of corals or other coastal seafloor species can be a powerful tool for tracking human impacts on natural ecosystems.
"Beyond the implications for coral health and resilience, this study demonstrates how many anthropogenic contaminants are escaping into marine ecosystems," said Megan Donahue, senior author on the paper and HIMB director. "We see increasing evidence that anthropogenic contaminants have broad cumulative impacts, undermining the resilience of coastal ecosystems."
This study underscores the urgent need to reduce human impacts on the marine environment to protect marine and human health. Looking ahead, Quinlan and the team are searching for ways to enrich coral tissue nitrogen and energy reserves in controlled experiments to determine whether those increases lead to more resilient corals.
Publication details
Zachary A. Quinlan et al, Coral metabolome quality and contaminant loads track human land use, Nature Communications (2026). DOI: 10.1038/s41467-026-74960-7
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Citation: How human activities compromise coral health and resilience (2026, July 17) retrieved 17 July 2026 from https://phys.org/news/2026-07-human-compromise-coral-health-resilience.html
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