Sonic Youth: Healthy Reef Sounds Increase Coral Settlement

Researchers at the Woods Hole Oceanographic Institution (WHOI) have shown that healthy coral reefs emit a symphony of sounds that can guide larval animals to suitable habitats. By replaying these sounds at degraded reefs, the researchers found that coral larvae settled at significantly higher rates. Nadège Aoki, a doctoral candidate at WHOI and the first author of the paper published in Royal Society Open Science, explained that broadcasting the soundscape of a healthy reef to damaged reefs could potentially aid in coral recolonization. This discovery highlights the importance of acoustic cues in the coral life cycle and suggests a novel approach to restoring degraded coral reefs.

In a study conducted by researchers at the Woods Hole Oceanographic Institution (WHOI), it was demonstrated that the soundscape of coral reefs plays a crucial role in determining where coral larvae settle. The researchers conducted experiments in the U.S. Virgin Islands using larvae from Porites astreoides, commonly known as mustard hill coral. They distributed the larvae at three reefs along the southern coast of St. John, with one relatively healthy reef (Tektite) and two more degraded reefs (Cocoloba and Salt Pond). At Salt Pond, an underwater speaker system was used to broadcast healthy reef sounds recorded at Tektite, while no sounds were played at the other two reefs. The researchers found that significantly more coral larvae settled at Salt Pond, with settlement rates up to 7 times higher compared to the other reefs. The highest settlement rates were observed at a distance of five meters from the speakers, suggesting that the enriched sound environment positively influenced coral settlement. This study highlights the importance of the soundscape in guiding coral larvae to suitable habitats and suggests a potential strategy for restoring degraded coral reefs.

In a study led by marine biologist Aran Mooney from the WHOI, it was found that settlement rates of coral larvae decreased with distance from underwater speakers broadcasting healthy reef sounds. This decrease in settlement rates was attributed to the added sound and not other factors, indicating that sound plays a significant role in coral settlement. The researchers observed higher settlement rates at a degraded reef (Salt Pond) where healthy reef sounds were played compared to two other reefs (Cocoloba and Tektite) where no sounds were played. Surprisingly, there was not much difference in settlement rates between the more-degraded Cocoloba and the healthier Tektite reefs, contrary to previous findings. This discrepancy may be due to changes in Tektite's soundscape over the years, potentially indicating declining reef health. Overall, the study suggests that sound can be a valuable tool for rebuilding degraded reefs and highlights the importance of maintaining a healthy reef soundscape.

In response to the decline in coral reefs, researchers emphasize the urgent need for scalable solutions. Coral reefs are vital ecosystems supporting marine biodiversity, protecting coastlines, and providing resources for millions worldwide. However, half of all coral reefs have been lost in the last 30 years. The study led by Nadège Aoki and Aran Mooney suggests that enhancing reef sounds can boost settlement rates of coral larvae, offering a promising strategy for coral restoration. By broadcasting healthy reef sounds in nurseries or wild reefs, settlement rates could be increased, aiding in reef recovery efforts. While monitoring reef conditions is necessary post-settlement, replicating acoustic environments is relatively simple compared to other cues influencing coral settlement. This research highlights the potential of soundscapes as a scalable tool for reef restoration, offering hope for the future of coral reefs worldwide. To learn more, go to Woods Hole’s article https://www.whoi.edu/press-room/news-release/sonic-youth-healthy-reef-sounds-increase-coral-settlement/