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The new analysis highlights underappreciated dimensions of modern coral reef degradation, said Lueders-Dumont, of the Department of Earth and Environmental Sciences’ Stable Isotope Biogeochemistry Lab.1

Human activity has lessened the resilience of modern coral reefs by restricting the food-fueled energy flow that moves through the food chains of these critical ecosystems,  an international team of researchers in the journal Nature. Examining otoliths—fish ear stones that are preserved in marine sediments across millennia—the team developed and applied a nitrogen isotope method to 7,000-year-old fossils in order to reconstruct ancient reef food webs directly for the first time, according to Boston College Senior Research Associate Jessica Lueders-Dumont, a lead researcher on the project.

Human activity has lessened the resilience of modern coral reefs by restricting the food-fueled energy flow that moves through the food chains of these critical ecosystems, r an international team of researchers in the journal Nature. Examining otoliths—fish ear stones that are preserved in marine sediments across millennia—the team developed and applied a nitrogen isotope method to 7,000-year-old fossils in order to reconstruct ancient reef food webs directly for the first time, according to Boston College Senior Research Associate Jessica Lueders-Dumont, a lead researcher on the project.

The new analysis highlights underappreciated dimensions of modern coral reef degradation, said Lueders-Dumont, of the Department of Earth and Environmental Sciences' Stable Isotope Biogeochemistry Lab.

Compared to "pristine" coral reef ecosystems from time periods before widespread human impacts, today's  host food chains that are 60–70% shorter and fishes that are 20–70% less functionally diverse, the study found.

"We discovered that on healthier Caribbean reefs, fish communities drew on a wider variety of food sources," she said. "On degraded reefs, diets have become homogenized—different fish are increasingly eating the same limited set of resources. In the past, individual fish could afford to be choosy; today many are left with whatever is available. It's like going from a vibrant neighborhood of restaurants to a single, stripped-down menu."

This loss of functional diversity means that modern coral reef ecosystems are more prone to collapse. Biodiversity hotspots that support at least a quarter of marine species, coral reefs are being degraded by human-driven factors such as rising temperatures, overfishing, and nutrient runoff.

Because these impacts began long before systematic monitoring, scientists have lacked a clear ecological baseline of an undisturbed reef food web. Such a measuring stick is essential for setting realistic conservation goals.

Date Added to MERLOT:

February 12, 2026

Created by:

jackwido ternax

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