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.

I know what you did last winter: Bowhead whale unusual winter presence in the Beaufort Sea

Nikoletta Diogou – niki.diogou@gmail.com

Twitter: @NikiDiogou
Instagram: @existentialnyquist

University of Victoria
Victoria, BC V5T 4H3
Canada

Additional authors: William Halliday, Stan E. Dosso, Xavier Mouy, Andrea Niemi, Stephen Insley

Popular version of 1aAB8 – I know what you did last winter: Bowhead whale anomalous winter acoustic occurrence patterns in the Beaufort Sea, 2018-2020
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018030

The Arctic is warming at an alarming pace due to climate change. As waters are warming and sea ice is shrinking, the arctic ecosystems are responding with adaptations that we only recently started to observe and strive to understand. Here we present the first evidence of bowhead whales, endemic baleen whales to the Arctic, breaking their annual migration and being detected year-round at their summer grounds.

Whales, positioned at the top of the food web, serve as excellent bio-indicators of environmental change and the health of marine ecosystems. There are more than 16,000 bowhead whales in the Bering-Chukchi-Beaufort (BCB) population in the Western Arctic. The BCB bowheads spend their winters in the ice-free Bering Sea, and typically start a journey early each spring of over 6000 km to summer feeding grounds in the Beaufort Sea, returning to the Bering Sea in early fall when ice forms on the Beaufort Sea (Figure 1). But how stable is this journey in our changing climate?

Figure 1. Map showing migration route of BCB bowhead whales and the wider study area.

The Amundsen Gulf (Figure 1), in the Canadian Arctic Archipelago of the Beaufort Sea, is an important summer-feeding area for the BCB whales. However, winter inaccessibility and harsh conditions year-round make long-term observation of marine wildlife here challenging. Passive acoustic monitoring has proven particularly useful for monitoring vocal marine animals such as whales in remote areas, and offers a remarkable opportunity to explore where and when whales are present in the cold darkness of Arctic waters. Figure 2 shows examples of two types of bowhead whale vocalizations (songs and moans) together with other biological and environmental sounds recorded in the Amundsen Gulf.

Figure 2. Examples of spectrograms recorded in the Amundsen Gulf of bowhead whale songs on the left, and bowhead whale moans on the right. Spectrograms are visual representations of sound, indicating the pitch (frequency) and loudness of sounds as a function of time. Spectrograms on the left include bearded seal calls (trills) interfering with the bowhead songs. Spectrograms on the right include other ambient sounds (ice noise) that interfere with the bowhead moans. Image adapted from authors’ original paper.

Examples of characteristic calls of bowhead whales recorded during 2018-2019 in the southern Amundsen Gulf.

In September of 2018 and 2019 we deployed underwater acoustic recorders at five sites in the southern Amundsen Gulf and recorded the ocean sound for two years to detect bowhead whale calls and quantify the whale’s seasonal and geographic distribution. In particular, we looked for any disruptions to their typical migration patterns. And sure enough, there it was.

A combination of automated and manual analysis of the acoustic recordings revealed that bowhead whales were present at all sites, as shown for 3 sites (CB50, CB300 and PP) in Figure 3. Bowhead calls dominated the acoustic data from early spring to early fall, during their summer migration, confirming the importance of the area as a core foraging site for this whale population. But surprisingly, the analysis uncovered a fascinating anomaly in bowhead whale behavior: bowhead calls were detected at each site through the winter of 2018-2019, representing the first clear evidence of bowhead whales overwintering at their summer foraging grounds (Figure 3). This is a significant departure from their usual migratory pattern. However, analysis of the 2019-2020 recordings did not indicate whales over-wintering that year. Hence, it is not yet clear if the over-wintering was a one-time event or the start of a more stable shift in bowhead whale ecology due to climate change. The variability in bowhead acoustic presence between the two years may be partly explained by differences in sea ice coverage and prey density (zooplankton), as summarized in Figure 4.

Figure 3. Number of days with acoustic detections per month for bowhead whales for sites CB50 (blue), CB300 (green), and PP (red) in 2018-2019. The yellow shaded areas represent time periods at each station when the ice concentration was below 20% (“ice-free”), grey areas when ice concentration was 20%-70% (“shoulder season”), and white areas when ice concentration was greater than 70%. Image adapted from authors’ original paper.

Figure 4. Graphical summary of the objectives and major results of the study.

The findings of this study have important implications for understanding how climate change is affecting the Arctic ecosystem, and highlights the need for continued monitoring of Arctic wildlife. Passive acoustic monitoring can provide data on how whale ecology is responding to a changing environment, which can be used to inform conservation efforts to better protect Arctic ecosystems and their inhabitants.

Baby Seals Show Off Vocal Skills #ASA183

Baby Seals Show Off Vocal Skills #ASA183

The pups possess an innate control of their voice and an understanding of rhythm.

Media Contact:
Ashley Piccone
AIP Media
301-209-3090
media@aip.org

NASHVILLE, Tenn., Dec. 9, 2022 – Humans appear to be one of the only animals capable of speech, which requires a range of skills and mental abilities. Among them, vocal learning — the ability to learn to produce new sounds —is critical for developing language. Only a handful of animals possess this trait, including humans, bats, whales, seals, and elephants.

Andrea Ravignani studies the vocal learning of seal pups. Credit: Connie Edwards/Kleve Zoo

However, simply possessing the ability to create new sounds is not enough to unlock language. Studying whether animals possess additional language-related skills can help us understand what it takes to learn speech and reveal the history of its evolution.

Andrea Ravignani of the Max Planck Institute for Psycholinguistics will discuss his work linking vocal learning with vocal plasticity and rhythmic capacity in his session, “Vocal learning, chorusing seal pups, and the evolution of rhythm.” The presentation will take place on Dec. 9 at 9:50 a.m. Eastern U.S. in Grand Hall A, as part of the 183rd Meeting of the Acoustical Society of America running Dec. 5-9 at the Grand Hyatt Nashville Hotel.

Ravignani and colleagues studied seal pups’ vocal plasticity, or how well they can adjust their own voices to compensate for their environment. They found that seal pups can change the pitch and volume of their voices, much like humans. The ability to change volume is common, but changing pitch, or fundamental frequency, is rare in animals.

“Seals may have this capacity due to convergent evolution: vocal plasticity may be a trait which evolved independently in multiple lineages due to similar evolutionary pressures,” said Ravignani. “For the case of humans and seals, plasticity and vocal learning may be associated with either advanced breathing control or singing abilities in both species.”

The team also tested the ability of seal pups to identify rhythmic sounds using recordings of other seals. They altered some of those recordings by changing tempos and adding rhythms to see how the young seals would react. Seal pups paid significantly more attention to recordings with regular rhythms and fast tempos.

“We can conclude that very young and untrained seals can discriminate between other seals’ vocalization based on their rhythmic properties,” said Ravignani. “Another mammal, apart from us, shows rhythm processing and vocalization learning; perhaps these two skills coevolved in both humans and seals.”

———————– MORE MEETING INFORMATION ———————–
Main meeting website: https://acousticalsociety.org/asa-meetings/
Technical program: https://eppro02.ativ.me/web/planner.php?id=ASAFALL22&proof=true

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 300 to 500 word summaries 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
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting or virtual press conferences, contact AIP Media Services at media@aip.org.  For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America (ASA) 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/.

Fish & Shrimp & Seals, Oh My! Soundscapes of Hawaiian monk seal habitats are dominated by biophony

Kirby Parnell – keparnel@hawaii.edu
@kirB15
@kirbyparnell15

Marine Mammal Research Program, University of Hawaii Manoa, Kaneohe, HI, 96744, United States

Karlina Merkens
Aude Pacini – twitter: @audepacini
Lars Bejder – twitter: @lbejder, @MMRP_UH

Popular version of 5aUW-Underwater soundscapes at critical habitats of the endangered Hawaiian monk seal, presented at the 183rd ASA Meeting.

The ocean is a noisy place. From chatty marine mammals to territorial fish and hungry shrimp, marine animals use sound to communicate, navigate, defend territories, and find food, mates, and safe spaces to settle down. However, human activities are negatively impacting the abilities of marine animals to effectively use sound for critical life functions. For the endangered Hawaiian monk seal with a population size of approximately 1,570 seals, we’re finding that vocal communication (Audio File 1) may play an important role for reproduction, yet we lack a foundational knowledge of the seals’ acoustic environment, better known as a soundscape. In this study, we found that biological sounds produced by snapping shrimp, fish, and seals dominate and shape the underwater soundscapes at critical habitats of the Hawaiian monk seal, with little input from man-made sources (Figure 1).

Figure 1 | A) Spectrogram of a 24-hour period on 11 May 2021 at Lehua Rock. A spectrogram is a visual representation of a sound where the x-axis is time, the y-axis is frequency (or pitch), and the color represents the amplitude of the sound (how loud or soft the sound is). The black icons indicate the source of the sound: snapping shrimp, boat, scuba divers, humpback whale song, Hawaiian monk seal vocalizations, and the vertical migration of the deep scattering layer. B) Spectrogram showing overlapping Hawaiian monk seal vocalizations from 0-1 kHz and humpback whale song from 0.5-5 kHz (listen to this in Audio File.

Figure 1 | A) Spectrogram of a 24-hour period on 11 May 2021 at Lehua Rock. A spectrogram is a visual representation of a sound where the x-axis is time, the y-axis is frequency (or pitch), and the color represents the amplitude of the sound (how loud or soft the sound is). The black icons indicate the source of the sound: snapping shrimp, boat, scuba divers, humpback whale song, Hawaiian monk seal vocalizations, and the vertical migration of the deep scattering layer. B) Spectrogram showing overlapping Hawaiian monk seal vocalizations from 0-1 kHz and humpback whale song from 0.5-5 kHz (listen to this in Audio File 1).

We sought to describe the underwater soundscape, or the acoustic environment, at locations that Hawaiian monk seals utilize for foraging, breeding, communication, and other critical life functions. We wanted to know 1) how loud are ambient (background) sound levels, 2) are sound sources biological, geophysical, or manmade, 3) how do sound sources and levels change throughout the day, and 4) how does the soundscape compare between the more-densely human-populated main Hawaiian Islands and the remote Northwestern Hawaiian Islands. To do this, we deployed passive acoustic recorders, known as SoundTraps, at four critical habitats of the Hawaiian monk seal: Rabbit Island, Oahu; Lehua Rock, Niʻihau; French Frigate Shoals; and Pearl and Hermes Reef. The SoundTraps recorded sounds from 20 Hz up to 24 kHz – this includes low-frequency sounds like earthquakes to high-frequency sounds like dolphin echolocation.

Our results indicate that sound levels are generally loud at these nearshore reef environments thanks to the persistent crackling sounds of snapping shrimp, low-frequency vocalizations of monk seals, and a variety of fish sounds. With little input from manmade sound sources, except at the popular scuba diving site Lehua Rock, we suspect that the elevated sound levels are indicative of healthy reef environments. This is good news for Hawaiian monk seals – less manmade noise means less acoustic masking making it easier to hear and “speak” to each other under water. We also opportunistically recorded sounds from Hurricane Douglas (Category 4) and a 6.2 magnitude earthquake around the time Kilauea began erupting. Overall, this study provides the first description of underwater soundscapes at Hawaiian monk seal critical habitats. These measurements can serve as a baseline for future studies to understand the impact of human activity on underwater soundscapes.

Offshore Wind Farms Could Disturb Marine Mammal Behavior

Offshore Wind Farms Could Disturb Marine Mammal Behavior

As the number and size of offshore turbines increase, so does the possible disruption to aquatic life.

Media Contact:
Larry Frum
AIP Media
301-209-3090
media@aip.org

DENVER, May 26, 2022 – When an offshore wind farm pops up, there is a period of noisy but well-studied and in most cases regulated construction. Once the turbines are operational, they provide a valuable source of renewable energy while emitting a constant lower level of sound that has not been fully investigated.

Frank Thomsen, of DHI, will discuss how this constant noise may impact wildlife in his presentation, “Operational underwater sound from future offshore wind turbines can affect the behavior of marine mammals.” The session will take place May 26 at 4:25 p.m. Eastern U.S. as part of the 182nd Meeting of the Acoustical Society of America at the Sheraton Denver Downtown Hotel.

Thomsen and colleagues reviewed published sound levels from operational wind farms to identify trends with turbine size. In general, the larger the turbine, the higher the noise emissions.

However, newer wind farms using quieter driving technology can to a certain extent cancel out the impact of larger turbines. Older gear box technology reaches disruptive levels for marine mammals up to 6.3 kilometers away. In contrast, newer direct drive turbines are expected to only impact animal behavior within a 1.4-kilometer radius.

“It is very unlikely that operational noise will lead to any injury or even hearing impairment, but behavioral changes could be a concern, as our study shows,” Thomsen said. “It’s possible that impact zones of individual turbines overlap, but that still does not mean that the wind farm is a no-go area for marine life. We see harbor porpoises frequently swimming in the vicinity of turbines.”

The long-term consequences of this noise on wildlife are still largely unknown. The impact could depend on the number of turbines and their overlapping affected areas.

In theory, the sound can lead to behavior changes in marine mammals and mask calls from whales, but harbor porpoises are frequently seen swimming in the vicinity of wind farms in Europe, so it may not be as simple as it seems.

“Since offshore wind farms have a relatively long lifespan, and there will be many of them, the potential impacts should not be overlooked,” said Thomsen. “The point of our work is to raise awareness.”

———————– MORE MEETING INFORMATION ———————–
USEFUL LINKS
Main meeting website: https://acousticalsociety.org/asa-meetings/
Technical program: https://eventpilotadmin.com/web/planner.php?id=ASASPRING22
Press Room: https://acoustics.org/world-wide-press-room/

WORLDWIDE PRESS ROOM
In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 word summaries of presentations written by scientists for a general audience and accompanied by photos, audio and video. You can visit the site during the meeting at https://acoustics.org/world-wide-press-room/.

PRESS REGISTRATION
We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America (ASA) 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/.

DeepSqueak Tool Identifies Marine Mammal Calls

DeepSqueak Tool Identifies Marine Mammal Calls

User-friendly deep learning model analyzes bioacoustics signals from whales, dolphins

Media Contact:
Larry Frum
AIP Media
301-209-3090
media@aip.org

DENVER, May 23, 2022 – Lurking beneath the ocean’s surface, marine mammals use sound for navigation, prey detection, and a wide range of natural behaviors. Passive acoustic data from underwater environments can provide valuable information on these animals, such as their presence or absence within an area, their density and abundance, and their vocal response to anthropogenic noise sources.

As the size and number of acoustic datasets increase, accurately and quickly matching the bioacoustics signals to their corresponding sources becomes more challenging and important. This is especially difficult in noisy, natural acoustic environments.

Elizabeth Ferguson, from Ocean Science Analytics, will describe how DeepSqueak, a deep learning tool, can classify underwater acoustic signals at the 182nd Meeting of the Acoustical Society of America during her presentation, “Development of deep neural networks for marine mammal call detection using an open-source, user friendly tool.” The session will take place May 23 at 11:25 a.m. Eastern U.S. as part of the conference at the Sheraton Denver Downtown Hotel.

Spectrograms show how acoustic signals of different frequencies vary with time. They look like heat maps, with brighter regions indicating higher sound intensity at that frequency and time. DeepSqueak uses deep neural network image recognition and classification methods to determine the important features within spectrograms, then match those features to specific sources.

“Although we used DeepSqueak to detect underwater sounds, this user-friendly, open source tool would be useful for a variety of terrestrial species,” said Ferguson. “The capabilities of call detection extend to frequencies below the ultrasonic sounds it was originally intended for. Due to this and the capability of DeepSqueak to detect variable call types, development of neural networks is possible for many species of interest.”

DeepSqueak was originally developed to classify ultrasound signals from rodents, but its neural network framework allows the technique to adapt to detect sounds at other frequencies. Ferguson and her team used the method and data from hydrophones on the Ocean Observatories Initiative’s Coastal Endurance Array to detect humpback whales, delphinids, and fin whales, which have highly variable calls with a wide range of frequencies.

———————– MORE MEETING INFORMATION ———————–
USEFUL LINKS
Main meeting website: https://acousticalsociety.org/asa-meetings/
Technical program: https://eventpilotadmin.com/web/planner.php?id=ASASPRING22
Press Room: https://acoustics.org/world-wide-press-room/

WORLDWIDE PRESS ROOM
In the coming weeks, ASA’s Worldwide Press Room will be updated with additional tips on dozens of newsworthy stories and with lay language papers, which are 300 to 500 word summaries of presentations written by scientists for a general audience and accompanied by photos, audio and video. You can visit the site during the meeting at https://acoustics.org/world-wide-press-room/.

PRESS REGISTRATION
We will grant free registration to credentialed journalists and professional freelance journalists. If you are a reporter and would like to attend, contact AIP Media Services at media@aip.org. For urgent requests, staff at media@aip.org can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America (ASA) 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/.