Underwater Noise Pollution: Strategies For A Quieter Ocean

Underwater noise pollution is a pervasive problem, with shipping being one of the main causes. The blades of a vessel's propellers account for 85% of all shipping-related sounds. This can be mitigated by using more efficiently designed propellers, as demonstrated by Danish shipping company Maersk, who reduced acoustic output by 75% after installing upgrades on 11 of its fleet. However, this solution is costly, with Maersk spending over $100 million to retrofit their fleet. Other solutions include strategically managing water traffic, such as rerouting ships away from the feeding areas of endangered marine life and recommending slower speeds for large ships in specific waters. Additionally, the use of acoustic bubble curtains can reduce sonar disruption caused by offshore wind farms, while marine vibroseis can help reduce noise generated during seismic surveys for oil and gas reserves.

Reducing shipping noise

Shipping is one of the most pervasive types of underwater noise pollution. In particular, the noise generated by the blades of a vessel's propellers accounts for 85% of all shipping-related sounds. To reduce this, more efficiently designed propellers are available. Danish shipping company Maersk has installed upgrades on 11 of its fleet, reducing acoustic output by 75%. However, this is an expensive process, with Maersk spending over $100 million to retrofit their fleet.

Another way to reduce shipping noise is to strategically manage traffic on the water. For example, the Vancouver Fraser Port Authority in British Columbia has developed a voluntary program that asks ships and tugboats to reroute away from the feeding areas of endangered southern resident killer whales. The program also recommends slower speeds for large ships in specific waters in southwestern British Columbia to reduce underwater noise.

Regions will need to tailor their solutions to their own shipping traffic and infrastructure, the underwater landscape, and local marine life. For example, after the terrorist attacks on 11 September 2001, ship traffic was significantly reduced in the Bay of Fundy in Canada, resulting in a drop in underwater noise of six decibels.

In addition to reducing shipping noise, it is important to consider other sources of underwater noise pollution, such as seismic surveys used to locate oil and gas reserves, and offshore wind farms. To reduce the impact of these activities on marine life, techniques such as marine vibroseis and acoustic bubble curtains can be used to reduce acoustic energy output.

Using acoustic bubble curtains

One of the most pervasive types of underwater noise pollution is that generated by shipping, in particular, the noise generated by the blades of a vessel’s propellers, which account for 85% of all shipping-related sounds. The problem can be mitigated by strategically managing traffic on the water. For example, ships and tugboats can be rerouted away from the feeding areas of endangered marine life and slower speeds for large ships can be recommended in certain waters.

Another source of underwater noise pollution is seismic surveys used to locate oil and gas reserves underwater. A technique called marine vibroseis can be used to reduce the sounds generated during the detection of fossil fuel deposits.

Offshore wind farms can also cause significant sonar disruption to underwater life. Acoustic bubble curtains can be used to reduce acoustic energy output by as much as 95%. Acoustic bubble curtains are a series of bubbles that form a wall and block some of the sound being emitted from a source. They can be used to create a bubble curtain around the sites of offshore wind farms.

Bubble curtains can also be used to reduce the noise caused by pile drivers, which are used to build many major structures offshore.

Acoustic bubble curtains are an effective way to reduce underwater noise pollution caused by offshore wind farms and pile drivers. By creating a barrier of bubbles, acoustic bubble curtains can reduce acoustic energy output and protect marine life from the harmful effects of sonar disruption.

Reducing seismic survey noise

Underwater noise pollution is a pervasive issue, with shipping being one of the main sources of noise. The blades of a vessel's propellers account for 85% of all shipping-related sounds. To reduce this, more efficiently designed propellers are available. For example, Danish shipping company Maersk has installed upgrades on 11 of its fleet, reducing acoustic output by 75%. However, this can be costly, with Maersk spending over $100 million to retrofit their fleet.

Another way to reduce underwater noise pollution is to strategically manage traffic on the water. For example, the Vancouver Fraser Port Authority in British Columbia has implemented a voluntary program that asks ships and tugboats to reroute away from the feeding areas of endangered southern resident killer whales. They also recommend slower speeds for large ships in specific waters in southwestern British Columbia to reduce underwater noise.

Seismic surveys used to locate oil and gas reserves underwater are also a significant source of noise pollution. A technique called marine vibroseis uses more continuous and lower amplitude signals than traditional methods of surveying, which could help reduce the sounds generated during the detection of fossil fuel deposits.

Offshore wind farms can also cause significant sonar disruption to underwater life. This can be mitigated by introducing acoustic bubble curtains, which put a barrier of bubbles between the farm and the external area, reducing acoustic energy output by up to 95%.

Additionally, many major structures offshore are built using pile drivers, which can cause loud bursts of underwater sound. To reduce this noise, a bubble curtain can be created around the construction sites, blocking some of the sound being emitted.

Reducing pile driver noise

Underwater noise pollution is a pervasive issue, with shipping being one of the main causes. The blades of a vessel's propellers account for 85% of all shipping-related sounds. To tackle this, more efficiently designed propellers are available, which can significantly reduce acoustic output. However, retrofitting fleets with these new propellers can be costly.

Another way to reduce underwater noise pollution is to strategically manage water traffic. For example, the Vancouver Fraser Port Authority in British Columbia has implemented a voluntary program that asks ships and tugboats to reroute away from the feeding areas of endangered southern resident killer whales. Additionally, large ships are recommended to reduce their speed in specific waters in southwestern British Columbia to reduce underwater noise.

Seismic surveys used to locate oil and gas reserves underwater are also significant contributors to noise pollution. By adopting the marine vibroseis technique, which uses more continuous and lower amplitude signals, the sounds generated during fossil fuel deposit detection can be reduced.

Now, let's focus on reducing pile driver noise.

Pile drivers are commonly used in the construction of major offshore structures and can generate sudden bursts of loud underwater sound, potentially causing immediate damage to nearby marine life. To mitigate this issue, one effective method is to create a bubble curtain around the construction sites. Bubble curtains act as a barrier, forming a series of bubbles that block and absorb sound waves, significantly reducing the noise emitted from the source. This technique has been successfully employed by offshore wind farms, reducing acoustic energy output by up to 95%impact of pile driving on marine life and implement measures to minimise any potential harm. This may include conducting environmental impact assessments, implementing noise mitigation strategies, and ensuring proper monitoring and compliance with regulations.

By combining the use of bubble curtains and implementing strategic management of construction activities, the negative effects of pile driver noise on underwater life can be significantly reduced. These measures not only help protect marine ecosystems but also contribute to a more sustainable and environmentally conscious approach to offshore construction projects.

Reducing underwater traffic

In the aftermath of the terrorist attacks on 11 September 2001, a great lull fell over North America, above and below the water. Understandably, fewer people were travelling by air. But ship traffic was also significantly reduced, even as far north as the Bay of Fundy in Canada. As a result, underwater noise in the bay dropped by an incredible six decibels, and sounds at pitches below 150 hz were significantly reduced.

Ineffectually designed blades can lead to cavitation, which upsets the flow of water and causes fuel inefficiency, wasted energy and plenty of unnecessary decibels. To solve that problem, more efficiently designed propellers are available. Danish shipping tycoons Maersk have installed upgrades on 11 of its fleet, noting that acoustic output was reduced by 75%. However, the problem lies in the fact that Maersk spent over $100 million to retrofit their fleet.

Marine noise could also be mitigated by strategically managing traffic on the water. One promising example is a voluntary program developed by the Vancouver Fraser Port Authority in British Columbia. It asks ships and tugboats to reroute away from the feeding areas of endangered southern resident killer whales and recommends slower speeds for large ships in specific waters in southwestern British Columbia to reduce underwater noise. Ultimately, regions will need to tailor their solutions to their own shipping traffic and infrastructure, the underwater landscape and local marine life.

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