Underwater Noise Pollution Research Articles

Natural and shipping underwater sound distribution in the Northern Adriatic Sea basin and possible application on target areas

The underwater sound distribution generated by natural sources, shipping and trawling activities has been computed by the Quonops© modelling webservice for the Northern Adriatic Sea (NAS) during 2020, a year characterized by the COVID-19 lockdown restrictions. Modelling has been calibrated by using a year-long time series of field measurements covering the domain of interest. Sound levels (50th percentile) ranged between 75 and 90 dB re 1μPa for all the considered frequencies (63 Hz, 125 Hz, 250 Hz third octave bands). Noisier NAS areas match with the shipping lanes and the distribution of trawling activity. Pressure sound indices based on masking effect were computed for two Ecologically/Biologically Significant Marine Areas (EBSA) located in the NAS. Results indicated a significant contribution of vessel and fishery-generated noise to the local soundscape and provide a basis for addressing NAS underwater noise pollution, with special reference to the Marine Spatial Planning approach.

Pile driving noise impacts behavioral patterns of important East Asian juvenile marine fishes

The surge in renewable energy demand, particularly from offshore wind farm (OWF), raises concerns about underwater noise pollution during their construction. Despite extensive studies on underwater noise impacts in European and Western countries, local species targeted investigations are crucial for global application. We assessed how pile driving noise during OWF construction affected the behavior of three juvenile Korean fishes (Lateolabrax japonicus, Acanthopagrus schlegelii, and Platichthys stellatus) prevalent in East Asian seas. Pile driving noise playback induced rapid changes in L. japonicus and A. schlegelii swimming speed and group cohesion, with 40 % remaining un-habituated after 5 min. Notably, L. japonicus showed clear avoidance of the noise source, while P. stellatus behavior remained unchanged at all. Our findings confirm that even relatively low-intensity impulsive noise can alter fish behavior, potentially due to species-specific characteristics. Accumulated data will inform the development of strategies for smart OWF establishment, advancing sustainable energy practices.

Evaluation of acoustic environmental effects and improvement method of ecological fish-nest bricks in the Yangtze River Basin: A model-based case study

With the rapid development of the Yangtze River Basin, the issue of underwater noise pollution has become increasingly severe, which has adversely affected aquatic creatures, particularly fish. Ecological fish-nest bricks (EFNBs), a new type of eco-friendly revetment, can provide a favorable habitat for fish. However, its effects on the acoustic environment remain unclear. The finite element numerical simulation method of acoustic-structure coupling is adopted to explore the acoustic environment of EFNBs, analyzing the impact of sound source frequency (within 300 Hz), structural forms, and arrangement of these bricks on the internal sound pressure level. The sound pressure level distribution of A-EFNBs were also analyzed at a distance of 0–0.5 m from the opening. A method of acoustic environment improvement is proposed, which utilizes porous polyurethane sponge (PPS) sound-absorbing material to establish a conducive acoustic environment for fish in EFNBs. The study results indicate that at low frequencies of sound source (f ≤ 150 Hz), the sound pressure level within EFNBs slightly decreases compared to the adjacent areas without EFNBs. The sound pressure level variation within the bricks increases with sound source frequency. The peak sound pressure increases with the number of openings. Interval arrangements can in general decrease sound pressure by less than 20 dB. At higher frequencies(f＞200 Hz), the sound pressure level at the opening of the A-EFNBs tends to increase. However, the PPS sound-absorbing material substantially reduces the sound pressure level by 15 –55 dB, rendering it an effective method for improving the acoustic environment for fish. The PPS sound-absorbing material is more suitable for habitat improvement of black carp (Mylopharyngodon piceus) and grass carp (Ctenopharyngodon idellus) with relatively low hearing thresholds among the four famous Chinese carps. The research findings can serve as a reference for designing and implementing river ecological restoration projects.

An efficient model for underwater noise prediction during pile driving.

Underwater noise pollution from pile driving is now attracting increasing attention. However, most of the current numerical and semi-analytical models for predicting the noise are still expensive and time-consuming, and the near-field noise and far-field noise have to be obtained from different models. This paper proposes an efficient semi-analytical solution for predicting underwater noise in both near field and far field with only one model, whose computational efficiency is orders of magnitude higher than that of the finite element model. It is the first time that the Baranov-Novak thin-layer model for soil-pile interaction has been extended to the subject of underwater noise prediction during pile installation, taking into account pile-fluid-soil interaction. The solutions are obtained using the Laplace transform and the variable separation method. By comparing the prediction results with the five reported research cases, it is shown that the error of the proposed model is within reasonable limits for both near-field and far-field noise predictions.

Frequency-dependent temporary threshold shifts in the Eastern painted turtle (Chrysemys picta picta).

Testudines are a highly threatened group facing an array of stressors, including alteration of their sensory environment. Underwater noise pollution has the potential to induce hearing loss and disrupt detection of biologically important acoustic cues and signals. To examine the conditions that induce temporary threshold shifts (TTS) in hearing in the freshwater Eastern painted turtle (Chrysemys picta picta), three individuals were exposed to band limited continuous white noise (50-1000 Hz) of varying durations and amplitudes (sound exposure levels ranged from 151 to 171 dB re 1 μPa2 s). Control and post-exposure auditory thresholds were measured and compared at 400 and 600 Hz using auditory evoked potential methods. TTS occurred in all individuals at both test frequencies, with shifts of 6.1-41.4 dB. While the numbers of TTS occurrences were equal between frequencies, greater shifts were observed at 600 Hz, a frequency of higher auditory sensitivity, compared to 400 Hz. The onset of TTS occurred at 154 dB re 1 μPa2 s for 600 Hz, compared to 158 dB re 1 μPa2 s at 400 Hz. The 400-Hz onset and patterns of TTS growth and recovery were similar to those observed in previously studied Trachemys scripta elegans, suggesting TTS may be comparable across Emydidae species.

Exposure of satellite tagged bowhead whales (Balaena mysticetus) to transiting vessels in the Eastern Canadian Arctic

AbstractClimate change poses new challenges to Arctic marine mammals, with increasing vessel traffic and associated underwater noise pollution emerging as significant threats. The bowhead whale (Balaena mysticetus), an endemic Arctic cetacean, faces these new threats. The Eastern Canada‐West Greenland (ECWG) bowhead whale population migrates through areas with the highest levels of vessel traffic in the Canadian Arctic. Here, we document the spatial and temporal overlap between 36 satellite‐tagged ECWG bowhead whales and vessels equipped with Automatic Identification System (AIS) transponders during 2012–2017. We report 1,145 instances where vessels were within 125 km of a tagged whale, with 306 occurrences within distances ≤50 km. Overlap between vessels and tagged bowhead whales was quantified monthly within years to investigate individual whale encounter rates. Results indicate that ECWG bowhead whales encounter the majority (79%) of vessels annually during August–October, with the highest number of encounters (42%) observed in September. Encounter rates ranged from 0.25 to 0.51 vessels encountered per day per whale during August–October compared to <0.07 vessels per day in all other months in this study. To better inform conservation strategies, further research is required to assess bowhead whale behavioral responses relative to distance from vessels.

Not so silent spectators: How spectator vessels at international sailing regattas alter marine soundscapes

International sailing regattas are major sporting events often held within coastal marine environments which overlap with the habitats of marine species. Although races are confined to courses, the popularity of these events can attract large spectator flotillas, sometimes composed of hundreds of motorized vessels. Underwater noise from these flotillas can potentially alter soundscapes experienced by marine species. To understand how these flotillas may alter soundscapes, acoustic recordings were taken around racecourses during the 36th America's Cup in the Hauraki Gulf, New Zealand in 2021. Sustained increases in broadband underwater sound levels during the regatta (up to 17 dB re 1 μPa rms; 0.01–24 kHz) that extended beyond racecourse boundaries (>8.5 km) and racing hours were observed; very likely attributable to the increase in regatta-related vessel activity. Underwater noise pollution from spectator flotillas attending larger regattas should be considered during event planning stages, particularly when events occur in ecologically significance areas.

Increased Yangtze finless porpoise presence in urban Wuhan waters of the Yangtze River during fishing closures.

Wuhan, a highly urbanized and rapidly growing region within China's Yangtze Economic Zone, has historically been identified as a gap area for the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) based on daytime visual surveys. However, there has been a noticeable increase in porpoise sightings since 2020. This study employed passive acoustic monitoring to investigate porpoise distribution in Wuhan between 2020 and 2022. Generalized linear models were used to explore the relationship between shipping, hydrological patterns, light intensity, and porpoise biosonar activity. Over 603 days of effective monitoring, the daily positive rate for porpoise biosonar detection reached 43%, with feeding-related buzz signals accounting for 55% of all porpoise biosonar signals. However, the proportion of minutes during which porpoise presence was detected was 0.18%, suggesting that while porpoises may frequent the area, their visits were brief and mainly focused on feeding. A significant temporal trend emerged, showing higher porpoise biosonar detection during winter (especially in February) and 2022. Additionally, periods without boat traffic correlated with increased porpoise activity. Hydrological conditions and light levels exhibited significant negative correlations with porpoise activity. Specifically, porpoise sonar detections were notably higher during the night, twilight, and new moon phases. It is highly conceivable that both fishing bans and COVID-19 pandemic-related lockdowns contributed to the heightened presence of porpoises in Wuhan. The rapid development of municipal transportation and shipping in Wuhan and resulting underwater noise pollution have emerged as a significant threat to the local porpoise population. Accordingly, it is imperative for regulatory bodies to effectively address this environmental stressor and formulate targeted protection measures to ensure the conservation of the finless porpoise.

Numerical investigation of shipping noise in the Red Sea

Underwater noise pollution is a significant environmental issue that can have detrimental effects on marine ecosystems. One of the main sources of underwater noise pollution is ship traffic, which has been shown to negatively impact marine animals by masking communication signals and altering their behaviors. This study represents the first comprehensive analysis of underwater ship noise in the Red Sea, wherein noise maps of ships sailing through the main shipping lane in the Red Sea were simulated by integrating both anthropogenic and environmental variables. These maps offer valuable insights for policymakers, enabling them to make informed decisions and implement targeted mitigation efforts.

Noise Generation Mechanisms of Marine Composite Pipelines Excited by the Internal and External Flows

The marine pipeline is an important energy transportation platform today. It can cause underwater noise pollution due to sound radiation caused by pipeline vibration during oil and gas transportation. This study focuses on the noise-generation mechanisms of marine composite pipelines under internal and external flow excitation. We investigated the impact of different materials, diameters, and wall thicknesses on the sound radiation characteristics of the pipeline under internal flow excitation. The relationship between radiated sound power and flow velocity was analysed. Additionally, we discussed the radiated sound field of marine composite pipelines under external flow excitation. Our results show that the radiated sound power under internal flow excitation is over 20 dB higher than that under external flow excitation in the 10 Hz to 2000 Hz frequency range. We conducted an experimental test near Zhoushan city, China, where the internal flow was driven by a pump and the external flow represented ocean currents. The results confirmed that the main noise-generating mechanism of marine composite pipelines is internal flow excitation. The numerical findings were validated by the experimental test. Overall, this paper provides a foundation for future investigations into the sound radiation of marine composite pipelines.

Use of metamaterials to reduce underwater noise generated by ship machinery

Reducing underwater noise pollution from ship machinery is a significant challenge. Ship machinery usually operates at fixed speeds and emits tonal noise with large amplitudes at low frequencies. Conventional soundproofing materials are inadequate for absorbing tonal noise and require large thicknesses at low frequencies. Quarter-wavelength resonators effectively absorb sound at their fundamental frequency and odd harmonics. Still, the applicability of this solution is nevertheless limited by its length requirement, which becomes cumbersome at low frequencies and, thus, large wavelengths. This study explores different structured metamaterial designs based on labyrinth, coiled quarter-wavelength resonators, and hybrid configurations combining glass wool and coiled resonators. Analytical, numerical calculations, and experimental tests are carried out under normal plane wave incidence (using an impedance tube) and a diffuse acoustic field (in a small reverberant cabin). In particular, a numerical optimization based on a periodic unit cell model is used to optimize the hybrid configuration and analyze its behavior under variable plane wave incidence angles. Preliminary tests conducted in a water basin using a small, straightforward aluminum box equipped with some proposed designs indicate reductions in underwater noise levels. The proposed solutions offer limited-cost and compact solutions for mitigating machinery noise and, potentially, the preservation of marine ecosystems.

Aircraft-Produced Sonic Booms and Marine Life

With the advent of new-age supersonic aircraft such as NASA’s X-59, Boom Supersonic’s Overture, and Spike Aerospace’s S-512, there is an emergent need to investigate their environmental consequences. This review evaluates existing research and information to determine what is currently known about supersonic aircraft and their potential impacts on marine life through a three-step process. 1) Determining possible characteristics of sonic booms produced by the aircraft: the aircraft being evaluated in this article produce low-frequency (0.1-100 Hz) sounds with surface PLdBs (perceived surface loudness decibel levels) around 70-75 dB. 2) Assessing the behavior of similar sounds as they interact with the ocean: sonic booms have been observed to penetrate the ocean for 98-164 ft, but this depth can vary due to differences between the experimental and real-life flight conditions. A separate effect, produced by sonic booms’ contact with the ocean surface, may penetrate deeper as infrasound. 3) Evaluating the potential consequences of these sounds on marine life: the continuous production of sonic booms along flight paths worldwide raises concerns about possible noise pollution, adding to the existing issue of oceanic anthropogenic noise pollution. Existing literature on underwater noise pollution—with similar frequencies and comparable intensities—shows negative impacts on marine reproduction, communication, stress levels, and physical health. This review contributes to broader ongoing discussions surrounding the resurgence of supersonic aviation and its environmental impact. Further research is necessary to assess the impact that transoceanic supersonic flight could have on marine ecosystems to truly determine supersonic flight’s environmental footprint.

Metabonomics and Transcriptomics Analyses Reveal the Development Process of the Auditory System in the Embryonic Development Period of the Small Yellow Croaker under Background Noise.

Underwater noise pollution has become a potential threat to aquatic animals in the natural environment. The main causes of such pollution are frequent human activities creating underwater environmental noise, including commercial shipping, offshore energy platforms, scientific exploration activities, etc. However, in aquaculture environments, underwater noise pollution has also become an unavoidable problem due to background noise created by aquaculture equipment. Some research has shown that certain fish show adaptability to noise over a period of time. This could be due to fish's special auditory organ, i.e., their "inner ear"; meanwhile, otoliths and sensory hair cells are the important components of the inner ear and are also essential for the function of the auditory system. Recently, research in respect of underwater noise pollution has mainly focused on adult fish, and there is a lack of the research on the effects of underwater noise pollution on the development process of the auditory system in the embryonic development period. Thus, in this study, we collected embryo-larval samples of the small yellow croaker (Larimichthys polyactis) in four important stages of otic vesicle development through artificial breeding. Then, we used metabonomics and transcriptomics analyses to reveal the development process of the auditory system in the embryonic development period under background noise (indoor and underwater environment sound). Finally, we identified 4026 differentially expressed genes (DEGs) and 672 differential metabolites (DMs), including 37 DEGs associated with the auditory system, and many differences mainly existed in the neurula stage (20 h of post-fertilization/20 HPF). We also inferred the regulatory mode and process of some important DEGs (Dnmt1, CPS1, and endothelin-1) in the early development of the auditory system. In conclusion, we suggest that the auditory system development of L. polyactis begins at least in the neurula stage or earlier; the other three stages (tail bud stage, caudal fin fold stage, and heart pulsation stage, 28-35 HPF) mark the rapid development period. We speculate that the effect of underwater noise pollution on the embryo-larval stage probably begins even earlier.

Anthropogenic noise predicts sea turtle behavioural responses

Anthropogenic noise is a pollutant of global concern. While the effects of underwater noise pollution have been frequently studied in fish and mammals, our understanding of how this anthropogenic stressor affects marine reptiles is scant. Using a multichannel data logger equipped with a camera and hydrophone, we quantified behavioural responses of a free-ranging green turtle (Chelonia mydas) to vessel noise in the Galapagos Archipelago, an important nesting site in the eastern Pacific. We found that while travelling the turtle increased its vigilance with increasing vessel noise. However, when on the seabed the turtle did not increase its vigilance with increasing noise levels. Our findings illustrate that noise pollution has the potential to alter overall time budgets of animals. Identifying real-time responses of wild animals illustrate how in situ approaches allow to assess the effects of human activities on marine systems.

A Preliminary Snapshot Investigation of the Marine Soundscape for Malta: A Steppingstone towards Achieving ‘Good Ecological Status’

The ever-accelerating rate of research focusing on the issue of underwater noise pollution, particularly concerning low-frequency, continuous noise, has steadily been unveiling the myriad of detrimental ecological implications caused to marine life. Despite this, many European Member States, such as Malta, still lack solid monitoring and regulatory frameworks aimed at characterising and improving the state of the marine acoustic environment and achieving ‘Good Ecological Status’ in accordance with the Marine Strategy Framework Directive. This shortcoming is directly reflected in the complete absence of baseline information covering the quality of the national soundscape. This paper aims to serve as a preliminary investigation into continuous underwater noise generation within Maltese waters, focusing on two sites characterised by heavy marine activity: Ċirkewwa and the Grand Harbour. Digital signal processing software packages (dBWav version 1.3.4) were used to extract and analyse sound pressure levels from in situ recorded audio files. Further statistical analysis was also carried out so as to evaluate the resultant snapshot of the baseline marine soundscapes at both sites. Furthermore, AIS data were used to tentatively identify the identifiable sources of underwater noise pollution. Given the current information lacuna revolving around the issue of underwater noise pollution in Malta, this paper may serve as a pilot study, with the aim of bridging this knowledge gap and forming the basis of future national research for Maltese marine conservation.

Numerical investigation of shipping noise in the Red Sea

Underwater noise pollution is a significant environmental issue that can have detrimental effects on marine ecosystems. One of the main sources of underwater noise pollution is ship traffic, which has been shown to negatively impact marine animals by masking communication signals and altering their behaviors. This study represents the first comprehensive analysis of underwater ship noise in the Red Sea. It aims to generate noise maps of ships sailing through the main shipping lane in the Red Sea. The Range-dependentAcoustic Model (RAM), incorporating anthropogenic and environmental inputs, was utilized to predict maps of underwater ship noises. The application of RAM yielded maps showcasing the spatial and temporal distribution of underwater ship noise in the Red Sea, providing valuable insights for policy makers and facilitating targeted mitigation efforts, with implications for future research on the impacts of underwater noise pollution on marine life.

BIT ERROR PERFORMANCE ENHANCEMENT FOR UNDERWATER ACOUSTIC NOISE CHANNEL BY USING CHANNEL CODING

The harm that underwater noise pollution poses to aquatic ecosystems and the resources that support it are being acknowledged on a worldwide scale. Fisheries and ecotourism are only two of the important businesses that are impacted by noise pollution. Reducing underwater impact noise is a major challenge for underwater acoustic communication systems. However, the implementation of noise reduction measures (noise abatement) remains limited. Most communication systems assume that the noise is both additive and Gaussian. Underwater Acoustic Noise (UWAN) systems generally perform poorly because of the often large non-Gaussian components in intermittent noise in the ocean. This study presents an experimental model (Dolphin-EAR DE200 Series) sound channel noise underwater at Lake Diyala Hamrin, Iraq, using a hydrophone model. Low data volume, multipath propagation, low bandwidth, and higher bit error rate (BER) of received data are major issues for underwater communication systems. In this paper, the Underwater Acoustic Channel (UWAC) aspect is evaluated and an error performance term is determined from the noise in the Student's t-distribution. In addition, Signals using binary phase-shift keying (BPSK) and quadrature phase-shift keying (QPSK) are used to generate error power analysis.

Lockdown impact on dolphins as an aquatic health indicator and maintenance of sustainable Gangetic ecosystem: An overview

A healthy ecosystem is a subject matter of interest because of its rich biodiversity. But natural climatic changes, as well as various man-made anthropogenic factors, not only emit greenhouse gases into the atmosphere resulting in global warming but influence various ecosystems of the earth. The aquatic ecosystem is one such example where the dolphin, with its complex behaviour, is recognized as one of the most intelligent members. The natural hydrodynamic body system speeds up underwater and the SONAR system communication technology helps dolphins to work as an efficient aquatic health indicator. But human activities, including aquatic poaching and fishing, creating underwater noise pollution and undesirable infrastructures and producing debris from their generated wastes obstruct the proper functioning of these systems and ultimately contribute to their habitat loss. So, dolphins’ ( Gangetic ones in India) disappearance from their comfortable living zone was inevitable and observed in the past few decades as they migrated to areas with more favourable conditions. The available information related to the rejuvenation in the qualities of the Gangetic water and the restoration of the dolphin’s habitat during COVID pandemic confirmed the absence of the negative impact of human activities on the Gangetic ecosystem. Hence, identification of the important steps to be implemented by the concerned authorities in post-COVID situation and their maintenance by the common people is necessary to balance such important aquatic biodiversity in the long run, keeping the country’s developmental activities operational. This review article is an endeavour towards that direction.

Biosonar activity of the Indo-Pacific humpback dolphin (Sousa chinensis) near the tunnel section of the world’s longest cross-sea bridge—the Hong Kong-Zhuhai-Macao Bridge—is negatively correlated with underwater noise

Underwater noise pollution from the world’s longest cross-sea bridge—the Hong Kong-Zhuhai-Macao Bridge (HZMB)—which stretches across the Chinese White Dolphin National Nature Reserve (of the People’s Republic of China, PRC) in the Pearl River Estuary may affect the distribution of local humpback dolphins. In this study, static passive acoustic monitoring was applied to monitor biosonar activity of humpback dolphins and underwater noise adjacent to the tunnel section of the HZMB for more than one year. During the monitoring period, dolphin biosonar signals were detected on 88.5% of days. A significant temporal pattern occurred in dolphin biosonar activity and in anthropogenic noise. Biosonar activity was significantly higher at night than during the day, whereas underwater noise occurred more in the day than at night. Significantly more echolocation signals were detected in winter-spring than in summer-autumn, and highest acoustic activity occurred significantly more during high tide than at other tidal periods. In addition, the negative correlation between elevated underwater noise and dolphin sonar activity in winter suggests that dolphins may avoid noisy waters for short periods, perhaps due to auditory stress, but fish prey movement cannot be ruled out. These findings facilitate understanding activity patterns of humpback dolphins in the Pearl River Estuary and may contribute to conservation efforts.

Cross-sensory interference assessment after exposure to noise shows different effects in the blue crab olfactory and sound sensing capabilities

Underwater noise pollution is an increasing threat to marine ecosystems. Marine animals use sound in communication and orientation processes. The introduction of anthropogenic noise in their habitat can interfere with sound production and reception as well as with the acquisition of vital information through other sensory systems. In the blue crab (Callinectes sapidus), the statocyst is responsible for acoustic perception, and it is housed at the base of its first pair of antennae (antennule). The sensilla of the distal part of these antennule hosts the olfactory system, which is key for foraging. Given the anatomical proximity of the two sensory regions, we evaluated the possible interference of sound exposure with the crab ability to find food, by using an aquatic maze, and looked at the potential impairment of the righting reflex as well as at ultrastructural damages in statocysts. Although a significant effect was observed when looking at the time used by the animal to recover its habitual position (“righting reflex”), which was associated to lesions in the statocyst sensory epithelia, the time required to find food did not increase after the exposure to sound. When the crabs were exposed to natural sounds (marine background noise and sounds of their predators: Micropogonias undulates and Sciaenops ocellatus) they did not show significant differences in foraging behaviour. Although we found no unequivocal evidence of a negative impact of sound on olfactory capabilities, the study showed a clear righting reflex impairment correlated with ultrastructural damages of the statocysts. We argue that crab populations that cannot easily avoid noise sources due to their specific coastal distributions may incur in significant direct fitness costs (e.g. impairment of complex reflexes). This integrated approach to sound effect assessment could be used as a model for other invertebrate species to effectively monitor noise impact in marine environments.