Sounding Out Coral Larval Settlements #ASA188

Coral larvae are attracted to areas with other healthy coral structures, using cues like sound to seek them out.

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Natalie Levy, a post-doctoral researcher, counts settled coral larvae with an ultraviolet light on the synthetically coated microhabitat structures. Credit: O. Boulais

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.”

——————— MORE MEETING INFORMATION ———————
Main Meeting Website: https://acousticalsociety.org/new-orleans-2025/
Technical Program: https://eppro01.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASAICA25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
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ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE INTERNATIONAL COMMISSION FOR ACOUSTICS
The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.

‘Fishial’ Recognition: Neural Network Identifies Coral Reef Sounds

Faster identification of fish sounds from acoustic recordings can improve research, conservation efforts

CUREE, an autonomous underwater robot, is used by the researchers to collect acoustic data for analysis. Image by Austin Greene, Woods Hole Oceanographic Institution

WASHINGTON, March 11, 2025 – Coral reefs are some of the world’s most diverse ecosystems. Despite making up less than 1% of the world’s oceans, one quarter of all marine species spend some portion of their life on a reef. With so much life in one spot, researchers can struggle to gain a clear understanding of which species are present and in what numbers.

In JASA, published on behalf of the Acoustical Society of America by AIP Publishing, researchers from Woods Hole Oceanographic Institution combined acoustic monitoring with a neural network to… click to read more

From: JASA
Article: Automated acoustic voice screening techniques for comorbid depression and anxiety disorders
DOI: 10.1121/10.0035829

Turning Up Ocean Temperature & Volume – Underwater Soundscapes in a Changing Climate

Freeman Lauren – lauren.a.freeman3.civ@us.navy.mil

Instagram: @laur.freeman

NUWC Division Newport, NAVSEA, Newport, RI, 02841, United States

Dr. Lauren A. Freeman, Dr. Daniel Duane, Dr. Ian Rooney from NUWC Division Newport and
Dr. Simon E. Freeman from ARPA-E

Popular version of 1aAB1 – Passive Acoustic Monitoring of Biological Soundscapes in a Changing Climate
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018023

Climate change is impacting our oceans and marine ecosystems across the globe. Passive acoustic monitoring of marine ecosystems has been shown to provide a window into the heartbeat of an ecosystem, its relative health, and even information such as how many whales or fish are present in a given day or month. By studying marine soundscapes, we collate all of the ambient noise at an underwater location and attribute parts of the soundscape to wind and waves, to boats, and to different types of biology. Long term biological soundscape studies allow us to track changes in ecosystems with a single, small, instrument called a hydrophone. I’ve been studying coral reef soundscapes for nearly a decade now, and am starting to have time series long enough to begin to see how climate change affects soundscapes. Some of the most immediate and pronounced impacts of climate change on shallow ocean soundscapes are evident in varying levels of ambient biological sound. We found a ubiquitous trend at research sites in both the tropical Pacific (Hawaii) and sub-tropical Atlantic (Bermuda) that warmer water tends to be associated with higher ambient noise levels. Different frequency bands provide information about different ecological processes (such as fish calls, invertebrate activity, and algal photosynthesis). The response of each of these processes to temperature changes is not uniform, however each type of ambient noise increases in warmer water. At some point, ocean warming and acidification will fundamentally change the ecological structure of a shallow water environment. This would also be reflected in a fundamentally different soundscape, as described by peak frequencies and sound intensity. While I have not monitored the phase shift of an ecosystem at a single site, I have documented and shown that healthy coral reefs with high levels of parrotfish and reef fish have fundamentally different soundscapes, as reflected in their acoustic signature at different frequency bands, than coral reefs that are degraded and overgrown with fleshy macroalgae. This suggests that long term soundscape monitoring could also track these ecological phase shifts under climate stress and other impacts to marine ecosystems such as overfishing.

A healthy coral reef research site in Hawaii with vibrant corals, many reef fish, and copious nooks and crannies for marine invertebrates to make their homes.

Soundscape segmented into three frequency bands capturing fish vocalizations (blue), parrotfish scrapes (red), and invertebrate clicks along with algal photosynthesis bubbles (yellow). All features show an increase in ambient noise level (PSD, y-axis) with increasing ocean temperature at each site studied in Hawaii.

Putting Ocean Acoustics on the stage to address climate change

Kyle M. Becker – kyle.becker1@navy.mil

co-chair, Interagency Working Group on Ocean Sound and Marine Life (IWG-OSML)
Washington, DC 20001
United States

Thomas C Weber – member, IWG-OSML, Washington, DC
Heather Spence – co-chair, IWG-OSML, Washington, DC
Grace C Smarsh – Executive Secretary, IWG-OSML, Washington, DC

Popular version of 1aAB9 – Ocean Acoustics and the UN Decade of Ocean Science for Sustainable Development
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018031

The Acoustic Environment is, collectively, the combination of all sounds within a given area modified by interactions with the environment. This definition includes both the sounds of nature and human use and is used by the US National Park Service as a basis for characterizing, managing, and preserving sound as one of the natural resources within the park system. Thinking in terms of a theatre, the Acoustic Environment is where scenes emerge from the interaction of individual actors (or sources) with all other aspects of the stage (the environment). The audience (or receiver) derives information from a continuous series of actions and interactions that combine to tell a story. In developing the Ocean Decade Research Programme on the Maritime Acoustic Environment (OD-MAE https://tinyurl.com/463uwjk5) we applied the theatre analogy to underwater environments, where acoustic scenes result from the dynamic combination of physical, biological, and chemical processes in the ocean that define the field of oceanography. In the science of Ocean Acoustics, these highly intertwined relationships are reflected in the information available to us through sound and can be used as a means to both differentiate among various ocean regions and tell us something – stories – about processes occurring within the oceans. The use of sound for understanding the natural environment is particularly effective in the oceans because underwater sound travels very efficiently over large distances, allowing us to probe the vast expanses of the globe. As an example of this, the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is capable of monitoring nearly the entire volume of the world’s oceans for underwater nuclear explosions with only eleven underwater acoustic listening stations.

In the context of the UN Decade of Ocean Science for Sustainable Development (oceandecade.org), the OD-MAE program seeks to raise awareness about and support research related to the information available through sound that reflects the regional ocean environment and its state. For example, the noisiest places in the ocean have been found to be in Alaskan and Antarctic fjords where sound energy levels created by the release of trapped air by melting ice exceed that of many other sources, including weather and shipping[1]. Sound energy increases with melt rate as more bubbles are released, providing information about the amount of fresh water being added into the oceans along with other climate indicators.

Representative glacial environment. Image credit: National Park Service

Ambient Sound recorded near Hubbard and Turner Glaciers near Yakutat, AK. Credit: Matthew Zeh, Belmont University and Preston Wilson, Univ. of Texas at Austin

Similarly, in warmer climates, the acoustic environment of coral reefs can provide scientists an indication of a reef system’s health. Healthy reef systems support much more life and as a result more sound is produced by the resident marine life. This is evident when contrasting the sounds recorded at a healthy reef system to those recorded at a location that experienced bleaching owing to increased water temperature and climate change[2].

Representative healthy and degraded reef systems. Image credits NOAA

Sound of representative healthy reef system. Credit: Steve Simpson, University of Bristol, UK	Sound of representative degraded reef system. Credit: Steve Simpson, University of Bristol, UK

As a research program, the OD-MAE seeks to quantify information about the acoustic environment such that we can assess the current state and health of the oceans, from shallow tropical reefs to the very deepest depths of the ocean. Telling the stories of the ocean by listening to it will help provide knowledge and tools for sustainably managing development and even restoring maritime environments[3].

References:

[1] Pettit, E. C., Lee, K. M., Brann, J. P., Nystuen, J. A., Wilson, P. S., and O’Neel, S. (2015), Unusually loud ambient noise in tidewater glacier fjords: A signal of ice melt. Geophys. Res. Lett., 42, 2309– 2316. doi: 10.1002/2014GL062950.
[2] https://artsandculture.google.com/story/can-we-use-sound-to-restore-coral-reefs/ RgUBYCe8v8Ol0Q [last visited 5.3.2023]
[3] Williams, B. R., McAfee, D., and Connell, S. D.. 2021. Repairing recruitment processes with sound technology to accelerate habitat restoration. Ecological Applications 31( 6):e02386. 10.1002/eap.2386

Featured Image Credit: National Park Service