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, reports 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.