Scientists listened for porpoises inside a tidal-energy zone and discovered the tide itself can bury their clicks beneath 29 decibels of underwater noise

Tracking marine mammal echolocation clicks is complex due to noise in tidal energy zones.

Global offshore renewable projects are rapidly expanding to meet increasing clean power demand.

A technology rising in popularity is underwater turbines harnessing the energy from tides.

However, since strict permit regulations and increasing land scarcity limit onshore growth, developers are increasingly deploying offshore.

Researchers are consequently using acoustic monitoring to track potential marine wildlife impacts, but face background interference.

In what ways does ocean noise affect the accuracy of population measurement and risk assessment?

How modern clean power demand requires rapid offshore expansion

Electricity usage today differs widely from the power needs of a century ago.

Back then, grids were localized, with heavy industry and basic municipal lighting driving consumption.

After substantial technological evolution, modern society now experiences a much greater demand for electricity.

This surge is driven by widespread digitization and electrification, with data centers accounting for the highest usage.

Each year, the power requirements of data centers increase by nearly 20 percent.

When strict international climate regulations are added to the equation, it leads to a great need for clean power generation.

Nations must power major technological growth while simultaneously lowering carbon emissions to fight climate change.

To do so, renewable energy infrastructure must rapidly expand.

However, since strict permit regulations and increasing land scarcity limit onshore growth, developers are increasingly deploying offshore.

Coastal waters offer reliable, powerful resources on a large scale, driving a prospective clean power capacity of almost 5 terawatts.

Tapping the ocean’s power from above and below

The onshore wind power boom has been immense, but wind has also been dominating offshore energy deployment.

Across international waters, the collective global capacity has exceeded 92 gigawatts.

This dominance is credited to rapid technological advancements, high scalability, and consistent winds.

As a result, these turbines have become much larger, averaging over 10 megawatts each.

Despite this already driving a massive energy output, developers are seeking to go beyond ocean surface generation.

Beneath the surface, the ocean is hiding immense untapped power potential.

This is called tidal energy, which is harnessed using underwater turbines.

The technology captures energy from predictable, strong marine currents driven by gravitational force.

For the energy sector, tidal power represents the next frontier in marine renewable deployment.

Yet its potential impact on the marine environment remains relatively unknown.

This makes comprehensive ocean monitoring crucial to biodiversity conservation.

However, a recent study indicated that underwater noise creates complications.

Difficulties in tracking the impact of tidal turbines

As tidal energy generation rises in popularity, environmental impact studies are also increasing globally.

A team led by Gemma Veneruso and consisting of marine scientists conducted detailed research within a high-energy tidal zone.

The study’s goal was to establish the effects of underwater environments on marine monitoring.

Passive acoustic monitoring, which uses underwater microphones to track porpoise echolocation clicks, was the method focused on.

Tracking the turbulence of fast-moving coastal currents.

Audio data across different tidal cycles were recorded to measure background noise levels.

The movement of currents stirs up sediment, causing flow noise (turbulence), which interacts with biological signals.

Tidal flow significantly disrupts acoustic tracking.

It shifted by up to 29 decibels during a 12-hour cycle and varied across distances under 1,640 feet.

This interference masks porpoise clicks.

As a result, data are incorrect, misrepresenting where and when marine mammals use an area.

The study’s findings provide valuable insight for future tidal energy projects.

It highlights that intense flow noise must be accounted for to ensure marine life protection.

Data accuracy can be drastically improved by using dynamic detection thresholds that adapt to altering local currents.

Furthermore, placing the microphones closer together will account for spatial differences in underwater sound.

Ultimately, tidal turbines can reshape offshore power generation, but environmental impact studies must first factor in variables.

The study’s findings can be reviewed using: Veneruso, G, Chapuis, L, Hastie, G D, Le Vay, L & Cordes, L S 2025, ‘Tidal flow masks acoustic detections of harbour porpoises ( Phocoena phocoena ): implications for passive acoustic studies of cetaceans’, Journal of the Acoustical Society of America, vol. 158, no. 4, pp. 2883-2891. https://doi.org/10.1121/10.0039560.