In various sectors, including the maritime industry, monitoring underwater acoustics serves multiple purposes, particularly as most strive to become more sustainable. However, assessing the extent and repercussions of noise pollution on both people and the environment poses a set of challenges. Fortunately, ongoing advancements in technology, practices, and regulations enable the addressing of some of these pressing issues. Let’s explore how potential future trends and innovations will bring improvements in underwater sound measurement and mitigation.
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Why is underwater acoustics monitoring crucial?
It is crucial for all parties concerned to evaluate the underwater noise they generate, enabling the implementation of appropriate measures to diminish them. This proactive approach not only reduces their environmental impact but also ensures compliance with the regulations in force. To initiate this process effectively, it is pertinent to have a comprehensive understanding of the diverse sources of acoustic pollution.
What are the primary sources of underwater noise pollution?
Marine pollution is significantly exacerbated by acoustic disturbances, creating a substantial threat to both the overall marine ecosystems, with a global modification of the living ambient of the marine fauna. The main underwater sound sources, at a wide range of frequency bands, are:
- shipping traffic, mainly because of vessel propellers cavitation, engines and machinery, hull vibration, release of exhaust gases, flow of water around a ship’s hull sonar systems, vessel maneuvering, cargo handling, dropping and retrieval of anchors …;
- offshore projects that involve construction activities (installation of offshore structures such as platforms, undersea pipelines, wind turbine foundations…), pile driving, drilling equipment and machinery for oil and gas exploration and production, vessel traffic (supply, construction, maintenance) to and from offshore facilities …;
- fishing activities, from vessels’ engines and propellers, mechanical equipment for fishing gear handling (trawl nets, lines, and traps), hydraulic systems for the operation of winches and cranes, vessels maneuvering in and out of fishing grounds, acoustic fish-finders …;
- other marine activities such as waste dumping, dredging (movements of dredging vessels, placement of dredged material, cutter-head rotation at the end of a suction pipe, suction and discharge of water and sediments through pipelines…), seismic surveys to map the subsurface geology …;
- human (anthropogenic) activities in coastal areas: building of piers, docks, marinas, and waterfront structures, oceanic engineering projects (coastal protection, erosion control, construction of seawalls and breakwaters, underwater construction, or marine resource extraction), tourism and water-based recreational activities (tour boating, operations of cruise ships, jet skiing, and water sports), waste disposal, power plants especially those using water for cooling or as part of their processes…
Acoustic pollution has multiple adverse effects, especially on marine life (fishes, whales, invertebrates, and other particles in motion…). Cetaceans such as baleen whales, and toothed whales, rely on sound to navigate, communicate, hunt, find food, avoid danger… Whether it’s low or high frequencies, disturbances in acoustics can interfere with the behavior and life of marine mammals.
Temporary exposure to intense or prolonged noise levels may lead to a temporary decrease in hearing sensitivity (a phenomenon called Temporary Threshold Shift or TTS). But over time, when the auditory system is not more in capacity to recover, hearing damage known as a Permanent Threshold Shift (PTS) may occur, with severe outcomes, including injuries, stress, complications in growth and reproduction, or even death.
Why assess underwater noise?
Monitoring underwater sound holds significant importance for all companies engaged in operations at sea, whether along the coast or in deep waters. The shipping industry, oil and gas exploration, renewable energy, fishing and aquaculture, naval forces and defense operations, scientific and environmental organizations, research organizations, tourism … are some of the concerned sectors.
Based on the information gathered, pivotal decisions are made. For instance, in the face of serious potential threats to sensitive marine mammal habitats, critical migration routes, or other protected areas, ocean carriers might opt to adjust shipping lanes as a proactive measure. Likewise, in case of offshore activities that generate harmful underwater noise, operators might implement various measures to prevent immediate harm to marine species and, in the long run, minimize disturbances to marine life:
- modify their operational procedures
- temporarily suspend the project of certain activities until the risk is mitigated or better understood
- deploy noise mitigation technologies: use quieter equipment, install sound barriers or other engineering solutions
- establish exclusion zones or restricted areas, where certain activities are limited or prohibited.
Underwater noise has adverse effects on the marine environment, making it a significant concern for the International Maritime Organization (IMO) and the Marine Environment Protection Committee (MEPC). Consequently, industries operating in marine environments must actively monitor the impacts of these underwater sounds for diverse purposes, the main ones being:
- Studying the behavior, communication, migration patterns, and reproduction of marine animals, and the long-term effects of their business on these natural activities.
- Identifying and studying marine species based on their unique acoustic signatures to enhance the protection of endangered species.
- Managing fisheries by assessing the abundance and distribution of fish stocks. Knowledge about fish populations is hugely valuable information for sustainable fisheries management.
- Facilitating navigation for ships and submarines through the use of sonar systems, which employ acoustic signals to detect underwater objects, map the seafloor, and navigate through underwater terrain.
- Understanding climate patterns and ocean circulation. Changes in underwater acoustic signals can be linked to variations in water temperature, salinity, and currants.
However, underwater acoustics have other important uses.
- Mapping potential oil and gas reserves beneath the seafloor by conducting seismic surveys.
- Receiving warnings for natural disasters such as tsunamis. Changes in acoustic signals can indicate the presence of seismic activity.
- Facilitating communication via radio waves for activities like remotely operated vehicle (ROV) operations and underwater research.
- Detecting and tracking submarines for defense and security purposes, thanks to sonar technology.
Companies can leverage the wealth of information accessible through Google Scholar to get a deeper understanding of how noise threatens the underwater environment. Enhanced and up-to-date knowledge empowers them to make informed decisions, ensuring the sustained health and survival of natural resources and overall biodiversity in the long term.
Furthermore, among dedicated professional organizations, the Acoustical Society of America (ASA) publishes the “Journal of the Acoustical Society of America” (JASA). It serves as a platform for researchers, educators, and professionals in the field of underwater acoustics to collaborate, share knowledge, and promote best practices in acoustical science and technology.
They can publish original research articles, technical notes, and review papers, about findings, methodologies, and advancements. Recognized as a prestigious scientific journal, JASA is an essential resource for staying current with research trends and the latest developments regarding underwater acoustics.
What are the main challenges in underwater acoustics measurement?
All companies engaged in maritime activities are now aware of their obligation to assess the extent of underwater noise they generate and its environmental repercussions. Advancements in technology have equipped them with an array of cutting-edge tools, enabling precise and accurate measurements.
However, the process of monitoring is not without its challenges. Below are key factors that could impede the identification or processing of acoustic signals:
- Interference from background noise, both natural (waves, wind, rain, marine life) and human-made (shipping, construction, resource extraction), contributes to underwater noise pollution, making it difficult to isolate and detect specific acoustic signals.
- Propagation variability is influenced by ocean conditions such as changes in water temperature, salinity, and pressure, affecting the sound speed and propagation. Shallow water can introduce interactions and reflections, complicating signal processing.
- Observational limitations exist during nighttime or in deeper ocean regions, reducing visibility and hindering continuous observation of acoustic events.
- Data processing and analysis face challenges due to the vast amount of data generated by continuous monitoring, requiring sophisticated algorithms for efficient processing. Real-time monitoring applications may experience processing delays.
- In harsh underwater conditions, especially in deep-sea environments, equipment deployment, calibration, and maintenance might be technically and logistically challenging and expensive, affecting data accuracy and reliability.
- Equipment and operational costs pose constraints, as the acquisition, continuous measurement, and maintenance of specialized equipment, along with data analysis and personnel training, require significant financial resources. This may limit the widespread implementation of monitoring programs.
- Lack of standardization in regulatory and legal frameworks, including protocols and methodologies for underwater acoustic monitoring, can lead to inconsistencies in data collection and interpretation.
How can innovations improve underwater acoustics monitoring and mitigation?
Existing tools and innovations hold the potential to enhance underwater acoustics monitoring, helping businesses effectively address the challenges of all kinds that they face.
Advancements in sensor technology
Improved sensor technologies are now available in the acoustic communication market. This includes:
- modems that transmit and receive signals in various ranges and frequencies, enabling data exchange between submerged platforms like submarines, autonomous underwater vehicles (AUVs), and sensors. Such devices come with options for high bandwidth and long-distance communication.
- hydrophones (underwater microphones) receive acoustic signals and come in various sensitivities and directivity patterns, depending on the application.
- transponders that receive and retransmit acoustic signals, extending the communication capabilities or acting as underwater beacons for navigation and tracking.
These sensors could offer better signal-to-noise ratios and extended frequency ranges, enhancing the overall performance of underwater acoustic systems.
Development of Autonomous Underwater Vehicles (AUVs)
AUVs equipped with advanced underwater acoustic sensors will be increasingly used for ocean exploration, environmental monitoring, and underwater surveillance. These vehicles can operate autonomously, collecting data over extended periods and in remote or dangerous environments.
Further integration AI and ML
Artificial intelligence algorithms and acoustic trends in machine learning techniques can be employed to process large volumes of data. These technologies can help in identifying underwater acoustic trends, classifying underwater sounds, and improving the efficiency of data analysis based on sound speed profile, sound pressure, sound propagation, sound levels… Lately, cognitive acoustic communication has emerged, leveraging AI algorithms to optimize communication parameters, adapt to changing environmental conditions, and improve network performance.
Underwater communication systems
Enhanced underwater acoustic communication systems, both for point-to-point communication and sensor-networked systems will gain importance. Some specialists provide expertise in designing and integrating acoustic communication systems for specific applications, considering factors like user requirements, environmental conditions, and regulations. This may involve site surveys, equipment installation, and ongoing maintenance.
Advances in signal processing
New hardware advancements are complemented by continued improvements in signal-processing techniques. Sophisticated software is harnessed to filter noise, correct channel distortions, enhance signal transmission across multiple channels and classify underwater sounds.
Experts employ a Multi-Layer Perceptron (MLP) to process and analyze underwater sound data. This computational model comprises a multi-layered artificial neural network that is specifically designed and trained to make precise predictions, based on elements such as sound frequency content, amplitude variations, and temporal patterns provided at the input layer of this infrastructure. Dedicated network management software enables network configuration, performance analysis, and fault detection, contributing to more reliable and efficient communication.
Underwater acoustic imaging
Advancements in underwater acoustic imaging techniques can lead to clearer and higher-resolution images of underwater environments. This is essential for various applications, including underwater archaeology, oil and gas exploration, and environmental monitoring.
Environmental monitoring and conservation
Global underwater acoustics can play a significant role in monitoring and studying marine ecosystems. The development of advanced acoustic tools for tracking marine life, studying migration patterns, and assessing the impact of human activities on aquatic environments may continue to evolve.
Underwater navigation and mapping
Improved navigation and mapping systems utilizing underwater acoustics can contribute to more accurate underwater mapping and exploration. This is essential for applications such as offshore infrastructure inspection and underwater resource exploration.
Standardization and collaboration
Efforts to establish standards for underwater acoustic technologies and promote collaboration among researchers, industries, and regulatory bodies may increase. This could facilitate the development and adoption of new technologies in a more standardized and interoperable manner.
Renewable energy applications
Underwater acoustics may be utilized in the monitoring and maintenance of underwater structures associated with renewable energy sources such as offshore wind farms and tidal energy installations.
Addressing these challenges requires ongoing research, technological innovation, and collaboration among researchers, industries, and policymakers to improve the effectiveness of underwater acoustics monitoring and its applications.
Sinay, supplier of innovative solutions for maritime industries
At Sinay, our mission is to offer solutions that enhance the operational efficiency of maritime companies while enabling them to predict and mitigate their impact on ocean biodiversity (marine mammals, fishes, birds, and benthos) and carbon footprint. Mastering data is key to reaching that goal, ensuring a comprehensive and informed decision-making process.
Tailoring our approach to each company’s unique requirements, our team can deploy various IoT sensors for real-time data collection at sea. Our hub encompasses a suite of tools, including features for field underwater acoustics monitoring, among other environmental indicators. Our dedicated AI-based software centralizes the maritime data gathered in a secure space, for interpretation, insight extraction, and results visualization.
Additionally, our experts provide consultancy services for environmental impact assessment, conducting aerial or boat surveys, and facilitating wildlife observation. They may also guide companies in defining a strategic environmental-operational plan.
Frequently Asked Questions About Futur of Underwater Acoustics
Underwater acoustics monitoring is vital for evaluating and mitigating the environmental impact of noise generated by various maritime activities.
It ensures compliance with regulations, reduces environmental impact, and necessitates a comprehensive understanding of diverse acoustic pollution sources.
Challenges include interference from background noise, propagation variability influenced by ocean conditions, observational limitations during nighttime or in deeper ocean regions, data processing complexities, equipment deployment challenges, high costs, and lack of standardization in regulatory frameworks.
Innovations involve advancements in sensor technology, development of Autonomous Underwater Vehicles (AUVs), integration of AI and ML, improved underwater communication systems, advances in signal processing, underwater acoustic imaging, environmental monitoring, underwater navigation and mapping, standardization efforts, and applications in renewable energy.
Sinay offers tailored solutions to enhance operational efficiency while predicting and mitigating the impact on ocean biodiversity and carbon footprint.
Utilizing IoT sensors and AI-based software, Sinay enables real-time data collection, interpretation, and visualization for comprehensive and informed decision-making. Additionally, the company provides consultancy services for environmental impact assessment and strategic planning.
