Turning down the volume: tackling underwater noise pollution with innovation

Underwater noise is one of the most invisible yet impactful forms of marine pollution." — Gwenaël Desse, Chief Business Officer, GREENOV

What if the ocean wasn’t silent after all?

In this episode of BlueTech Around the World, we dive deep (literally) into one of the least known yet most urgent environmental issues: underwater noise pollution.

Joining us is Gwenaël Desse, Chief Business Officer at GREENOV.

After graduating from KEDGE Business School, he joined Naval Group, the French leader in defense naval systems. For five years, he worked on R&D projects and submarines , vessels that demand the highest standards of acoustic discretion.

That’s where he first became aware of the importance of underwater acoustics.

Driven by a desire to put his energy into ocean protection, he transitioned from the defense sector to environmental innovation.

In 2022, he joined GREENOV as Chief Business Officer and Today he shares the journey behind the SubSea Quieter®, a pioneering solution to reduce underwater industrial noise and protect marine ecosystems.

Sound Matters Beneath the Waves

Jean-Jacques Cousteau once called the ocean The Silent World, but that idea couldn't be further from reality. Beneath the waves, marine animals rely on sound the way humans rely on sight: for navigation, feeding, mating, and survival.

From whale songs traveling hundreds of kilometers to dolphin echolocation, sound is life in the ocean.

But today, this soundscape is under threat.

Noise from shipping, pile-driving, dredging, and industrial operations is creating acoustic chaos.

For marine species, it's not just disruptive, it's deadly.

In this episode, we had the unique opportunity to listen to a powerful audio clip, provided by GREENOV and its partner Chorus Acoustics. The sequence includes three layers of sound: the haunting song of a whale, followed by the mechanical rumble of a passing vessel, and finally the sharp, percussive impact of pile-driving.

The contrast is jarring and deeply illustrative of the problem we're trying to solve.

"Underwater noise pollution can mask whale songs, disrupt dolphin communication, and cause stress or disorientation across entire ecosystems," said Gwenaël.

 Don’t hesitate to listen to the full episode on your favorite podcast platform or on YouTube.

Defining the threat: What is underwater noise pollution?

This form of pollution refers to the human-generated sound waves that propagate through ocean waters. Unlike oil spills or plastic waste, it leaves no visual trace but can travel over 100 kilometers, especially low-frequency sounds.

Key impacts include:

• Interference with communication and migration patterns

• Physical harm from impulsive sounds (pile-driving, sonar)

• Disruption of feeding, mating, and navigation behaviors

And the victims?

Not just whales and dolphins. Scientific studies have found impacts on fish, invertebrates, seals, turtles, and entire marine ecosystems.

The regulatory push

The good news? Change is coming.

The EU Marine Strategy Framework Directive (2008) was the first major framework to address underwater noise. Germany and the Netherlands have since adopted measurable thresholds and seasonal restrictions.

Now, the movement is global. Countries like the U.S., Canada, Australia, and Taiwan are rolling out guidelines, while international bodies like the IMO are integrating underwater noise into their sustainability agenda.

"We’re seeing strong momentum across Europe and beyond. Regulation will be a major driver of change," Gwenaël emphasized.

Today, noise mitigation is no longer just a niche concern. It’s become a priority across the entire maritime value chain from insurers and offshore developers to marine contractors and energy providers.

Many large players now include acoustic experts in their teams, working closely with regulators and NGOs to understand impacts, conduct monitoring, and reduce noise at the source.

Introducing the SubSea Quieter®

So what can we do about it?

The SubSea Quieter® is a patented solution designed by GREENOV to actively reduce underwater noise from construction activities.

Its core innovation: a flexible 3D membrane panel inflated with air, creating an acoustic barrier that breaks the transmission of harmful low-frequency sounds.

But how does it actually work?

Let’s take a look at the physics.

Noise is essentially a wave of energy. Low-frequency noise, like the kind generated by pile-driving, travels far and wide, sometimes up to 700 kilometers.

This type of noise is especially harmful and difficult to block.

SubSea Quieter® panels are made from a patented membrane.

These two-meter-wide panels are connected via a system of pipes and air compressors. Once deployed, they are inflated underwater, forming a physical break in acoustic impedance, essentially changing the medium from water to air and back to water.

This shift disrupts the propagation of noise and significantly reduces its reach and impact.

"It's like wrapping a soundproof sock around the source of the noise," Gwenaël explained.

The SubSea Quieter® is customizable in length, shape, and deployment method depending on the depth, currents, wave height, and type of construction, whether it’s monopiles, jackets, dredging, or harbor works.

Key features:

• Patented air-inflated membrane system

• Adaptable design for different depths, currents, and seabeds

• Up to 35 dB reduction, significantly outperforming traditional bubble curtains

• Reduces CO2 emissions by eliminating the need for dozens of air compressors.

Adapting to offshore and coastal conditions

One of the strengths of the SubSea Quieter® lies in its adaptability.

For shallow harbor operations, the system is used to reduce both noise and turbidity. It’s deployed in calm waters (less than 20 meters deep) where dredging or small pile-driving projects are underway.

For offshore wind foundations, the approach is different. The system is mounted under the vessel that handles monopile installation. Picture it like a soundproof sleeve or “sock” that wraps around the monopile before the hammering begins. The system must be strong, reliable, and quick to deploy because offshore time is extremely costly.

"Every hour saved offshore is tens of thousands of euros saved," Gwenaël noted.

The economics of Silence

Beyond ecological impact, SubSea Quieter® delivers real operational and financial value:

• 5x more efficient than bubble curtains

• Saves €10-50 million per wind farm by eliminating extra vessels and compressors

• Cuts operational risks and downtime offshore

And when it comes to emissions, it’s a leap forward: a wind farm installation using SubSea Quieter emits 4 tons of CO2, compared to 15,000 tons with bubble curtains (Gwenaël)

"It’s not just about protecting marine life. It’s about building smarter and greener infrastructure."

The bigger picture: collaboration & next-gen solutions

Underwater noise mitigation is a multi-faceted challenge. Gwenaël outlined four complementary strategies:

1. Source Reduction – Modify ships and construction equipment to reduce the amount of noise generated. Electric or hybrid vessels are one step in this direction.

2. Propagation Reduction – Reduce the spread of noise using barriers like bubble curtains or SubSea Quieter®.

3. Receptor Protection – Protect marine life through timed construction schedules, often in collaboration with marine mammal observers or NGOs.

4. Alternative Foundations – Use floating wind turbines or tension-leg platforms that don’t require pile-driving at all.

GREENOV positions itself firmly within the propagation reduction category while staying connected to partners across the spectrum.

"Underwater noise mitigation isn’t a one-size-fits-all issue. It’s about finding the right mix of solutions for each project."

GREENOV is already working with NGOs, regulators, and acoustic monitoring experts to validate their technology and adapt it to new challenges, from deepwater floating wind to real-time adaptive systems.

"No one solution will fix this alone. We need collaboration across sectors to restore the ocean soundscape."

What’s next for GREENOV?

In 2024, GREENOV achieved major milestones:

• A successful prototype test in Saint-Nazaire harbor

• Basin testing in Marseille to validate performance in rough offshore conditions

Looking ahead to 2025:

• Industrialization of the SubSea Quieter®

• New international partnerships

• A fundraising round to support growth and R&D

"We’re building the future of underwater noise mitigation and we’re looking for partners who want to be part of the solution."

To learn more, visit https://greenov.green/

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