NEW ORLEANS, May 22, 2025 – Coral reefs are vital to marine biodiversity, but their livelihood is under threat due to climate instability and the impacts of human activities.

Rehabilitating marine environments requires innovative solutions. Océane Boulais, a doctoral student at the Scripps Institution of Oceanography, studies one of these potential solutions: the impacts of acoustics on coral larval recruitment and settlement.

After spawning, coral larvae drift or swim through the water column, seeking suitable sites to find a home to attach to along the ocean floor.

“Multiple chemical compounds have already been identified as environmental cues that stimulate this settling behavior, presumably by indicating to the larvae when other successful-settled coral structures are nearby,” said Boulais. “A growing body of evidence over the past 20 years is also finding that sound may be another such cue.”

Healthy reefs are acoustically rich environments, filled with fish croaks and shrimp snaps. Boulais and their collaborators mimicked these sound environments to study the effects of sounds on 19 artificial coral settlement modules placed in Kāneʻohe Bay, Oahu, Hawaii. The researchers recorded audio near a vibrant reef, which they replayed at various distances from their artificial microhabitats. The artificial microhabitats were coated with a bacteria designed to induce larval settlement, creating a suitable habitat for attracting coral larvae.

Boulais will present details on their findings about the impacts sound has on coral larvae Thursday, May 22, at 9:20 a.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23. Notably, there were significant increases in coral settlement close to the speakers.

The researchers are planning an additional data deployment in the summer of 2025. Boulais said they hope to ultimately develop scalable strategies to study larger reef structures with audiovisual remote sensing tools, using low-cost cameras for continuously monitoring the reef’s biodiversity.

“Innovative, interdisciplinary approaches — combining science, technology, and creativity — can offer powerful solutions to pressing environmental challenges like coral reef degradation,” Boulais said. “Ultimately, I hope this research inspires both urgency and hope for the future of coral reefs.”

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