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Sea Squirts React to Underwater Noise Through Vibrations, Not Sound Pressure
Confirmed
In Short: Til Böttner and Mareike Huhn from Ruhr-Universität Bochum are studying sea squirts, also known as tunicates, and have discovered that these marine invertebrates react to underwater noise through vibrations rather than sound pressure.
The researchers found that sea squirts, specifically the species Halocynthia papillosa, exhibit behavioral contractions in response to mechanical vibrations between 50 and 800 hertz, while remaining unaffected by sound pressure levels exceeding 130 decibels.
This finding challenges the common approach of examining sound pressure to determine the effects of underwater noise on marine organisms.
Ships and construction projects contribute significantly to underwater noise pollution, but the impact on stationary sea squirts is now understood to be mediated through substrate vibrations rather than acoustic sound pressure.
While the study focuses on sea squirts, it underscores the complexity of marine life's responses to environmental disturbances and highlights the need for a more nuanced understanding of underwater noise effects.
What's confirmed
- The researchers found that sea squirts, specifically the species Halocynthia papillosa, exhibit behavioral contractions in response to mechanical vibrations between 50 and 800 hertz, while remaining unaffected by sound pressure levels exceeding 130 decibels.
- This finding challenges the common approach of examining sound pressure to determine the effects of underwater noise on marine organisms.
- Ships and construction projects contribute significantly to underwater noise pollution, but the impact on stationary sea squirts is now understood to be mediated through substrate vibrations rather than acoustic sound pressure.
- While the study focuses on sea squirts, it underscores the complexity of marine life's responses to environmental disturbances and highlights the need for a more nuanced understanding of underwater noise effects.
What's still developing
- Til Böttner and Mareike Huhn are studying sea squirts. tunicates.
- One study shows that it is not the noise itself that triggers reactions in them.
- The researchers discovered that these animals do not respond to sound pressure so much as they do to vibrations.
- Surprisingly, the sea squirts showed no comparable reactions even at underwater sound pressure levels exceeding 130 dB, provided that substrate vibrations remained below the determined reaction thresholds.
- “The results show that sound pressure alone cannot explain the observed behavioral reactions,” Huhn concludes.
- “Further physiological and neurobiological studies are required to determine whether these receptors are stimulated by particle motion in the water or by vibrations transmitted via the substrate and the mantle,” says Böttner.
- Photo Credit: Courtesy of Ruhr-Universität Bochum Scientific Frontline: Extended "At a Glance" Summary : Tunicate Perception of Underwater Noise The Core Concept : Sea squirts are sedentary marine invertebrates that detect and react to anthropogenic underwater noise through substrate-borne vibrations rather than acoustic sound pressure.
- Ships and construction projects fill our seas with noise, but stationary sea squirts perceive it much differently from what we previously thought.
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