Underwater Noise Pollution Research Articles

An Analysis of Policy Options Available to the International Maritime Organization to Protect the Costa Rica Thermal Dome: Building the Case for a Particularly Sensitive Sea Area

Intense maritime traffic threatens marine habitats globally. The Costa Rica Thermal Dome (CRTD) is a biologically productive ocean region that experiences a high volume of maritime traffic, and its location is dynamic, representing a governance challenge for this marine area. The CRTD is a high seas upwelling system influenced part of the year by coastal jet winds off the coast of Nicaragua and Costa Rica. During parts of the year, the CRTD moves into the jurisdictional waters of the adjacent countries (Costa Rica, Nicaragua, Guatemala, and El Salvador). Because there is currently no cross-sectoral coordination or capacity to address multiple threats in high seas areas such as the CRTD, regulation must be implemented on a sector-by-sector basis. This document analyzes tools under the International Maritime Organization (IMO) to reduce the threats from international shipping in the marine environment, with particular emphasis on the CRTD. The IMO has the authority to regulate shipping activity globally and implement precautionary measures to avoid threats such as hazardous and noxious substances, ship-whale strikes, or underwater noise pollution. The following IMO tools were included in the analysis: ship routing measures and speed reductions, a Special Area under the International Convention for the Prevention of Pollution from Ships (MARPOL), and a Particularly Sensitive Sea Area (PSSA). The results of the analysis concluded that the implementation of a PSSA within the CRTD is the best option to address threats from international shipping, since it can combine a range of Associated Protective Measures under its single administrative structure.

Three-dimensional anthropogenic underwater noise modeling in an Arctic fjord for acoustic risk assessment

Sea-ice covering is drastically declining in the Arctic, opening new maritime routes and thus introducing underwater noise pollution in nearly pristine acoustic environments. Evaluating underwater noise pollution requires good acoustic propagation modeling to predict sound exposure levels. However, underwater noise modeling for acoustic risk assessments has often been carried out using simplistic propagation models, which approximate a 3D propagation in several planes (Nx2D), instead of using full 3D propagation models. However, Nx2D propagation models are impractical for winding geography and steep bathymetry as found in Arctic fjords. The purpose of this study is to estimate disturbance and masking effects on Arctic animal species from shipping noises, modeled through a traditional Nx2D BELLHOP model and a full 3D BELLHOP model. Classical Nx2D propagation modeling largely underestimates the anthropogenic noise footprint in Arctic fjords compared to using a full 3D propagation model.

Finite Element Solution for Dynamic Mechanical Parameter Influence on Underwater Sound Absorption of Polyurethane-Based Composite

Underwater noise pollution, mainly emitted by shipping and ocean infrastructure development of human activities, has produced severe environmental impacts on marine species and seabed habitats. In recent years, a polyurethane-based (PU-based) composite with excellent damping performance has been increasingly utilized as underwater sound absorption material by attaching it to equipment surfaces. As one of the key parameters of damping materials, dynamic mechanical parameters are of vital importance to evaluating the viscoelastic damping property and thus influencing the sound absorption performance. Nevertheless, lots of researchers have not checked thoroughly the relationship and the mechanism of the material dynamic mechanical parameters and its sound absorption performance. In this work, a finite element model was fabricated and verified effectively using acoustic pulse tube tests to investigate the aforementioned issues. The influence of the dynamic mechanical parameters on underwater sound absorption performance was systematically studied with the frequency domain to reveal the mechanism and the relationship between damping properties and the sound absorption of the PU-based composite. The results indicate that the internal friction of the molecular segments and the structure stiffness were the two main contributors of the PU-based composite's consumption of sound energy, and the sound absorption peak and the sound absorption coefficient could be clearly changed by adjusting the dynamic mechanical parameters of the composite. This study will provide helpful guidance to develop the fabrication and engineering applications of the PU-based composite with outstanding underwater sound absorption performance.

A real-time passive acoustic monitoring system to detect Yangtze finless porpoise clicks in Ganjiang River, China

Phocoenidae live in fresh, coastal waters where they often share a significant portion of their habitat with humans. As a result, local activities (e.g., coastal fisheries and shipments) cause underwater noise pollution and threaten their ecosystem. To better conserve the habitat of porpoises, we aimed to study their activities in these waters by recording their echolocation clicks using a passive acoustic monitoring (PAM) system. However, because the off-line PAM instruments were often used in the past that need to be periodically deployed and recovered, data acquisition is typically obtained and analyzed in batches, rather than in real-time. A real-time PAM detection system would help minimize the impact of underwater noise on approaching porpoises. Furthermore, issues of bad quality data–with gaps due to loss or damage of the off-line PAM instruments–could be avoided with a real-time detection system. Therefore, in this study, we developed the Real-time Porpoise Click Detector-II (RPCD-II), equipped with a digital hydrophone, main memory (2 TB storage), a central processing unit, and a wireless transmission module. We deployed the RPCD-II under a docked fishing vessel at the Ganjiang River in Yangzi Zhou Town Fisheries Village, Nanchang City (8–9 December 2021), where it recorded signals of Yangtze finless porpoise and produced a real-time report. To validate the results of RPCD-II, another underwater sound recorder, the SoundTrap 300HF (ST), was also set up (as a control device) under the docked fishing vessel. Both devices recorded consistent results of 9330 clicks, further demonstrating RPCD-II’s ability for the real-time detection of Yangtze finless porpoise in the field.

Underwater Anthropogenic Noise Pollution Assessment in Shallow Waters on the South-Eastern Coast of Spain

Anthropogenic noise is a growing threat to marine life due to the incrementation of human activity in the marine environment. In Europe, the Directive 2008/56/EC of the European Parliament and of the Council was published with the aim of establishing a framework for community action in the field of marine environmental policy. The directive introduces underwater acoustic energy, as detailed in Descriptor 11, and stipulates that the member states should set the threshold levels at which a good environmental status can be achieved by means of long-term monitoring campaigns. This research presents the results of a long-term underwater noise monitoring campaign with a duration of three years in the port of Cartagena located on the south-eastern coast of Spain, focusing on the monthly and annual variation patterns of low-frequency continuous noise. The acquired data are classified according to the source of the acoustic noise into shipping, other anthropogenic, and natural noise measurements. These three groups of measurements are processed in order to obtain one-third octave band levels centered at 63 and 125 Hz, as well as the overall bandwidth of unweighted Sound Pressure Level (SPL). The analysis of the measurements shows an increase in the annual average overall band of 4 and 3 dB of the natural and shipping noise, respectively, from 2013 to 2015. This monitoring campaign provides accurate acoustic values to establish threshold levels to achieve good environmental status and recommendations to conduct monitoring programs and regulations to control underwater noise pollution.

Underwater Noise Level Recordings from a Water Intake Pontoon and Possible Impacts on Yangtze Finless Porpoises in a Natural Reserve.

Simple SummaryRelocation of endangered freshwater cetaceans in natural reserves is an effective conservation strategy to recover their populations. However, due to historical reasons, some natural reserves have facilities that cannot be removed, such as water intake pontoons that are important for residents nearby. These facilities generate underwater noise which may affect cetaceans. To investigate the potential impacts of underwater noise from water intake pontoons on freshwater cetaceans, this study measured such noise within a Yangtze finless porpoise (Neophocaena asiaeorientalis) nature reserve, analyzed its effects on porpoise behavior, vocalization, and hearing, and explored porpoise adaptation to the transient holding pen environment. This study provides a reference for assessing whether human facilities have impacts on freshwater cetaceans.Underwater noise pollution caused by human activities may affect freshwater cetaceans to different degrees. To analyze the impacts of water intake pontoons on Yangtze finless porpoises (Neophocaena asiaeorientalis), this study collected underwater noise data from such a pontoon in a nature reserve, plotted the power spectral density of acoustic signals, and calculated the root mean square sound pressure levels and the magnitude of sound source levels. The 1/3-octave sound pressure level root mean square values at the transient holding pens were <18.0 kHz, 39.5−60.0 kHz, which were slightly higher than the Yangtze finless porpoise hearing threshold curve values and therefore could be perceived. However, the results indicated that the porpoises would not develop a temporary hearing threshold shift. Meanwhile, pontoon noise did not interfere with the porpoises’ high-frequency acoustic signal nor did it affect their echolocation; it significantly interfered with their low-frequency acoustic signal, however, and the mother–child communication of the finless porpoises was affected, but this effect was quickly compensated due to the limited space range of the holding pens. Through this study of Yangtze finless porpoises, this paper provides a reference for assessing whether human facilities have impacts on freshwater cetaceans.

Composing with cetaceans: Countering human exceptionalism through a practical zoömusicology

There is something paradoxical about the fact that while whales and dolphins produce some of the most complex vocalizations on Earth, they have little political representation or ‘voice’ and despite the success of past anti-whaling campaigns, continue to face existential threats from entanglement, ship strikes and underwater noise pollution. In this article, I argue that this paradox is sustained by a belief in human exceptionalism – exemplified by the claim that music is unique to humans – and review biological and musicological evidence that contradicts this claim. Overcoming the paradox may require more than logical argument, however, and I survey the use of humpback whale song field recordings in works of human music, analysing them along the dimensions of ‘distance’ and ‘difference’. I argue that although it is important to recognize the continuity between human music and humpback song, a more effective use of whale song recordings also requires attention to be paid to the differences between human and whale vocalizations to avoid the risk of collapsing into naïve anthropomorphism. Such an animalcentric compositional voice would operate according to the ideals of ‘difference without distance’ and ‘proximity without indifference’ to facilitate empathic relationships between humans and other animals.

Impact of Anthropogenic Activities on Underwater Noise Pollution in Venice

We illustrate the implementation and results of a field experiment, consisting of recording continuous signal from a hydrophone 3 m deep in the Venetian lagoon. We simultaneously recorded audio signal through a microphone placed on a nearby pier. We investigate the potential of this simple instrumental setup to explore the small touristic boat traffic contribution to the underwater noise. The ultimate goal of our work is to contribute to quantifying underwater noise pollution due to motorboat passages and its impact on the ecosystem. Efforts such as ours should help to identify measures that could diminish noise pollution, focusing specifically on the aspects that are most disruptive to underwater life. After this preliminary test, more work can be planned, involving the deployment of a larger network of similar instruments around the lagoon. At this point, we can conclude that (i) our instruments are sensitive enough to detect motorboats and identify some of their characteristics; (ii) the area of interest is characterized by a large (approx. 20 dB) day/night difference in ambient noise; and (iii) the historic center of Venice and its immediate surroundings are particularly noisy, in comparison to other similarly studied locations.

Association between porpoise presence and fish choruses: implications for feeding strategies and ecosystem-based conservation of the East Asian finless porpoise.

The associations between feeding activities and environmental variables inform animal feeding tactics that maximize energetic gains by minimizing energy costs while maximizing feeding success. Relevant studies in aquatic animals, particularly marine mammals, are scarce due to difficulties in the observation of feeding behaviors in aquatic environments. This data scarcity concurrently hinders ecosystem-based fishery management in the context of small toothed-cetacean conservation. In the present study, a passive acoustic monitoring station was deployed in an East Asian finless porpoise habitat in Laizhou Bay to investigate potential relationships between East Asian finless porpoises and their prey. The data revealed that porpoises were acoustically present nearly every day during the survey period. Porpoise detection rates differed between spring and autumn in concert with activities of fish choruses. During spring, fish choruses were present throughout the afternoon, and this was the time when porpoise vocalizations were the most frequently detected. During autumn, when fish choruses were absent, porpoise detection rates decreased, and diurnal patterns were not detected. The close association between fish choruses and finless porpoise activities implies an "eavesdropping" feeding strategy to maximize energetic gains, similar to other toothed cetaceans that are known to engage similar feeding strategies. Underwater noise pollution, particularly those masking fish choruses, could interrupt finless porpoises' feeding success. Fisheries competing soniferous fishes with finless porpoise could impact finless porpoise viability through ecosystem disruption, in addition to fishing gear entanglement.

Behavioral responses to predatory sounds predict sensitivity of cetaceans to anthropogenic noise within a soundscape of fear

SignificanceAcoustic signals travel efficiently in the marine environment, allowing soniferous predators and prey to eavesdrop on each other. Our results with four cetacean species indicate that they use acoustic information to assess predation risk and have evolved mechanisms to reduce predation risk by ceasing foraging. Species that more readily gave up foraging in response to predatory sounds of killer whales also decreased foraging more during 1- to 4-kHz sonar exposures, indicating that species exhibiting costly antipredator responses also have stronger behavioral reactions to anthropogenic noise. This advance in our understanding of the drivers of disturbance helps us to predict what species and habitats are likely to be most severely impacted by underwater noise pollution in oceans undergoing increasing anthropogenic activities.

Strained listening: sensing underwater noise pollution in Calder Harben’s ‘Bodies of Water’

In 2017 the artist Calder Harben (b.1986) produced a sound installation titled Bodies of Water, which engages with the increasing violence of underwater noise pollution. In this immersive installation, participants encounter looped recordings of low-frequency noise pollution in a dimly lit gallery space. The work of art asks visitors to imagine the experience of marine species whose lives are dramatically disrupted by the noise produced by ships and vessels used for extractive activities, shipping commercial goods and recreational purposes. In her article, Chanelle Lalonde explores how Harben’s work ethically engages with the issue of water and noise pollution not merely by bringing attention to it, but in its development of a listening practice that requires reckoning with the limitations of the human sensorium. Bodies of Water, Lalonde argues, demands a process of continuous straining; a mode of listening that is not extractive, but one that embraces unfamiliarity.

A REVIEW OF PRACTICAL METHODS FOR REDUCING UNDERWATER NOISE POLLUTION FROM LARGE COMMERCIAL VESSELS

Underwater noise pollution from shipping is of considerable concern for marine life, particularly due to the potential for raised ambient noise levels in the 10-300Hz frequency range to mask biological sounds. There is widespread agreement that reducing shipping noise is both necessary and feasible, and the International Maritime Organization is actively working on the issue. The main source of noise is associated with propeller cavitation, and measures to improve propeller design and wake flow may also reduce noise. It is likely that the noisiest 10% of ships generate the majority of the noise impact, and it may be possible to quieten these vessels through measures that also improve efficiency. However, an extensive data set of full scale noise measurements of ships under operating conditions is required to fully understand how different factors relate to noise output and how noise reduction can be achieved alongside energy saving measures.

Влияние разработки нефтяных и газовых месторождений на окружающую среду Арктики

This article will focus on the analysis of environmental impacts directly related to the development of offshore oil and gas fields in the Arctic, namely, hydrocarbon spills, pollutants, and underwater noise pollution.

Effect of wavy leading edge on hydrofoil-turbulence interaction noise

In order to solve the underwater noise pollution and improve the acoustic stealth performance of underwater vehicles, NACA0020 was bionically modified according to the structure of the leading edge tubercles of humpback fin. The flow field and noise characteristics of the hydrofoil-turbulent interaction model before and after the modification were studied by using the large eddy simulation and the FW-H equation. The results show that the wavy leading edge can effectively reduce the turbulence interaction noise of the hydrofoil, especially the broadband noise after 89.55 Hz. The overall sound pressure level(OASPL) directivity of the wavy leading edge hydrofoil are the same as the original hydrofoil, and both have dipole characteristics, but the noise value in all directions is reduced to a certain extent. The OASPL is calculated and analyzed in different frequency bands. The results show that the OASPL has a best reduction in 1 000-5 000 Hz frequency band, and the noise can be reduced up to 12.6 dB. Through the analysis of flow field, it is concluded that the noise reduction effect of wavy leading edge mainly relates to the decrease in pressure fluctuation at leading edge and the decrease in coherence of vortex in spanwise direction caused by the enhancement of spanwise flow.

Riverside underwater noise pollution threaten porpoises and fish along the middle and lower reaches of the Yangtze River, China

The Yangtze River exhibits a high biodiversity and plays an important role in global biodiversity conservation. As the world's busiest inland river in regard to shipping, little attention has been paid to underwater noise pollution. In 2017, the underwater noise level in 25 riverside locations along the middle and lower reaches of the Yangtze River mainly at night time were investigated by using passive acoustic monitoring method. Approximately 88% and 40% of the sampled sites exhibit noise levels exceeding the underwater acoustic thresholds of causing responsiveness and temporary threshold shift, respectively, in cetacean. Noise pollution may impose a high impact on fish with physostomous swim bladders and Weberian ossicles, such as silver carp, bighead carp, goldfish and common carp, whereas it may affect fish with physoclistous swim bladders and without Weberian ossicles, such as lake sturgeon and paddlefish, to a lesser extent. Noise levels reductions of approximately 10 and 20 dB were observed in the middle and lower reaches, respectively, of the Yangtze River over the 2012 level. The green development mode of the ongoing construction of green shipping in the Yangtze River Economic Belt, including the development of green shipping lanes, ports, ships and transportation organizations, may account for the alleviated underwater noise pollution. Follow-up noise mitigation endeavors, such as the extension of ship speed restrictions and the study and implementation of the optimal navigation speed in ecologically important areas, are required to further reduce the noise level in the Yangtze River to protect local porpoises and fish.

The development of a transdisciplinary policy framework for shipping companies to mitigate underwater noise pollution from commercial vessels

One of the newly emerging environmental issues is underwater noise pollution. It has both negative environmental and socio-economic impacts and threatens sustainable shipping. While other types of shipping pollutants have been regulated and societal awareness has been raised, due to the intangible characteristics of underwater noise pollution, there is neither societal awareness nor an international legally binding instrument to mitigate underwater noise pollution. This paper aims to raise awareness of ship owners regarding UWN pollution by introducing the sources of UWN pollution, as well as proposing a transdisciplinary policy for shipping companies to mitigate UWN pollution from their ships. The proposed policy is aligned with IMO's initial GHG strategy, especially the Energy Efficiency Design Index, Energy Efficiency Existing Ship Index, and Enhanced Ship Energy Efficiency Management Plan. This multi-dimensional approach will make stakeholders more enthusiastic to tackle underwater noise pollution while enhancing the efficient use of capacities and resources.

Regression methods for evaluation of the underwater noise levels in the Slovenian Sea

Abstract in English Anthropogenic underwater noise pollution of seas and oceans caused by shipping can have negative effects on marine animals. The aim of this study was to evaluate quantitatively how much the underwater noise levels in the Slovenian Sea were influenced by anthropogenic pressures and meteorological parameters in the period from 2015 until 2018. For this purpose, correlation method and least squares multiple linear regression analysis were used. The results of this study show that the correlation of underwater noise levels with the dredging activity is significant but low, while correlation with the ship densities is insignificant, which could be due to reduced sound wave propagation in the shallow sea levels. Correlation of the underwater noise levels with the wind speed was significant but low to medium, which could be explained by the breaking waves generated by the wind that produced sound.

Study of the Sound Escape with the Use of an Air Bubble Curtain in Offshore Pile Driving

Underwater noise pollution generated by offshore pile driving has raised serious concerns over the ecological impact on marine life. To comply with the strict governmental regulations on the threshold levels of underwater noise, bubble curtains are usually applied in practice. This paper examines the effectiveness of an air bubble curtain system in noise reduction for offshore pile driving. The focus is placed on the evaluation of noise transmission paths, which are essential for the effective blockage of sound propagation. A coupled two-step approach for the prediction of underwater noise is adopted, which allows us to treat the waterborne and soilborne noise transmission paths separately. The complete model consists of two modules: a noise prediction module for offshore pile driving aiming at the generation and propagation of the wave field and a noise reduction module for predicting the transmission loss in passing through an air bubble curtain. With the proposed model, underwater noise prognosis is examined in the following cases: (i) free-field noise prediction without the air bubble curtain, (ii) waterborne path fully blocked at the position of the air bubble curtain while the rest of the wave field is propagated at the target distance, (iii) similarly to (ii) but with a non-fully blocked waterborne path close to the seabed, and (iv) air bubble curtain modeled explicitly using an effective medium theory. The results provide a clear indication of the amount of energy that can be channeled through the seabed and through possible gaps in the water column adjacent to the seabed. The model allows for a large number of simulations and for a thorough parametric study of the noise escape when a bubble curtain is applied offshore.

The sources and prevalence of anthropogenic noise in Rockfish Conservation Areas with implications for marine reserve planning

Underwater noise pollution is a recognized threat to marine life. In British Columbia, Canada, Pacific rockfish (Sebastes spp.) were historically overfished, prompting the establishment of Rockfish Conservation Areas (RCAs). However, there are no restrictions prohibiting vessel transits in RCAs. We hypothesized that RCAs do not protect rockfish from sub-lethal harm from noise. We compared noise levels at three RCAs with adjacent unprotected reference sites from August 2018–June 2019. While RCAs had lower levels of noise overall than reference sites, this trend was inconsistent; some RCA sites had higher levels of noise during certain time periods than non-RCA sites. A vessel noise detector was the best predictor of noise level over three frequency bands (20–100 Hz, 100–1000 Hz, 1–10 kHz), and predicted sound levels which could mask rockfish communication. We conclude that RCAs do not reliably protect rockfish from noise pollution, and recommend further study into potential impacts on stock recovery.

Understanding the legal development and challenges regarding underwater noise pollution in Spain and Norway

Noise is one of most important pollution that affects to human health, but in aquatic ecosystem its impact is higher than terrestrial. Noise is included in environmental acts only by sectorial mechanism but, in 2010, this vision changed. Ecosystem approach was incorporated in Spanish acts with first legal instrument for protecting from holistic perspective internal seas. From the European Union built news regulations about marine policies from ecosystem approach, with two essentials acts, Maritime Spatial Planning and Marine Strategies. In this paper, we analyse these mechanisms in Spain and Norway; we make a descriptive research about the legal mechanism for managing the underwater noise pollution generates by human activities. And we compare different mechanism to use with priority in these countries and we try to answer that if it is necessary to incorporate another instrument, such as an underwater noise licence, for any anthropogenic activity with to noise limits.