Underwater noise
Contents
Sources of underwater sound
Sound is transmitted in water by pressure fluctuations. Sound in seawater has various origins: environmental, biotic and anthropogenic. Environmental sound is caused by e.g. breaking waves, turbulent water motions, earthquakes, thunder and raindrops. Biotic sound is produced by marine animals. Anthropogenic sound is what we call 'underwater noise' here. It is produced by human activities such as trawling, dredging, military exercises, oil and gas exploration, seismic surveys, commercial shipping, recreational boats, windfarm construction (e.g. pile driving), sounds emitted by turbines, etc. These noise sources have grown tremendously over the past century. High-intensity impulsive noise is produced by pile driving, underwater blasting, seismic exploration and active sonar application. Low-frequency stationary noise is generated by various ships and vessels.[1]
Sound perception by marine animals
Underwater noise can travel large distances before being dissipated. For example, pile driving can elicit strong avoidance behavior of some marine animals even at a distance of 20 km. A highly sensitive animal, the bottle nose dolphin, suffers auditory injury within 100 m of the pile-driving location, and exhibits behavioral disturbance up to 50 km. Similarly, behavioral disturbance of minke whales may occur as far as 40 km from the pile driving site. [2]
Marine mammals have highly developed hearing mechanisms with ears adapted to hearing in underwater environments. Cephalopods and decapods (e.g. squids, crabs) can sense water-borne vibrations through ciliated sensory cells or through the statocysts and the chordotonal organs. Some fish species have a swim bladder connected to the inner ear for sound detection. Fishes without a swim bladder can sense acoustic pressure through particle motion. Clams and mussels sense vibrations through sensory systems of mechanoreceptors and chemoreceptors in the mantle, collar, and foot and also within the muscles that control the position of the foot.[3][4]
Importance of sound for marine animals
Biotic sound is produced by fish, invertebrates, marine mammals and other marine organisms, and plays an important role in communication, orientation, mate and prey detection, and echolocation. Swimming of pelagic animals and burrowing and feeding of benthic animals produce sound. Some fishes can produce special sounds by vibrating their swim bladder, other species produce sound by rubbing hard parts of their body.[1][3]
Many marine organisms depend on the interpretation of acoustic information of their environment for their survival. Animals use sound vibrations to learn more about their environment, predators, prey, potential mates, and competitors. Therefore, anything that interferes with the animal's ability to detect sounds, can affect their survival as individuals and populations. Noise pollution can affect marine organisms’ acoustic communication through physiological damage of the hearing system and through auditory masking where the perception of one sound is affected by the presence of another sound. Anthropogenic noise can drown out biologically important cues or signals, with possibly detrimental consequences such as the inability to find shelter or the right migratory route, finding food (prey), or even detecting a predator.[5]
Impacts of underwater noise on marine animals
Exposure to intense sound can cause not only acute changes in hearing sensitivity that recover over time, but in some cases also hearing loss that does not recover to pre-exposure levels. For example, low-frequency noise exposure caused permanent and substantial alterations of the sensory hair cells of the statocysts in several cephalopod species (squid, octopus, cuttlefish). Exposure to air-gun blasting caused ablated hair cells of the sensory epithelial hair cells in the pink snapper, which did not recover until 58 days after exposure. Seismic surveys with air guns were reported as the cause for atypical mass strandings of giant squids along the Asturian coast in 2001 and 2003. [6]
There is strong evidence that noise pollution can lead to a decline in population recruitment of some marine species such as scallops and crabs. There are also several reports of declines in fish catch rates as a consequence of anthropogenic noise, for example for rockfish, cod, haddock and saithe.[7]
In addition to the behavioural responses to anthropogenic underwater noise, changes in the expression profile in genes related to oxidative stress, energy homeostasis, metabolism, respiration and immune response have been observed in biomarker analyses.[4] Physiological changes have been reported in sessile invertebrates such as bivalves and sea squirts. Exposure to high-level noise from a seismic water gun led to increased levels of stress-related neurotransmitters in beluga whales. The impact of ship noise exposure on the immune system was manifested in dysregulation of the haemolymphatic circulatory sytem in the European spiny lobster.[8] Other ship noise exposure impacts on the immune system were detected in beluga whales and lined seahorses. Marine organisms tend to reduce their food intake and increase their metabolic rate, thereby usually displaying a reduction in growth and other morphological effects. Lined seahorses had significantly smaller body weights when exposed to loud noise from aquarium systems and noise exposure also caused a significant increase in metabolism and a reduction in growth rate in brown shrimp.[1]
Evaluation of the impacts of underwater noise
It is difficult to isolate the impacts of anthropogenic noise from other environmental stressors, such as pollution, climate change, and ocean acidification, in field studies. Conducting the investigation in the laboratory seems to be a good solution to isolate noise from such other environmental stressors. However, the results obtained do not represent the real natural conditions.[1]
Related articles
References
- ↑ 1.0 1.1 1.2 1.3 Peng, C., Zhao, X. and Liu, G. 2015. Noise in the Sea and Its Impacts on Marine Organisms. Int. J. Environ. Res. Public Health 12: 12304-12323
- ↑ Bailey, H., Senior, B., Simmons, D., Rusin, J., Picken, G. and Thompson, P.M. 2010. Assessing underwater noise levels during pile-driving at an offshore windfarm and its potential effects on marine mammals. Mar. Pollut. Bull. 60: 888–897
- ↑ 3.0 3.1 Roberts, L. and Elliott, M. 2017. Good or bad vibrations? Impacts of anthropogenic vibration on the marine epibenthos. Sci. Total Environ. 595: 255-26
- ↑ 4.0 4.1 El-Dairi, R., Outinen, O. and Kankaanpää, H. 2024. Anthropogenic underwater noise: A review on physiological and molecular responses of marine biota. Marine Pollution Bulletin 199, 115978
- ↑ Slabbekoorn, H., McGee, J. and Walsh, E.J. 2018. Effects of man-made sound on terrestrial mammals. In: Slabbekoorn, H., Dooling, R., Popper, A., Fay, R. (eds) Effects of Anthropogenic Noise on Animals. Springer Handbook of Auditory Research, vol 66. Springer, New York pp. 243–276
- ↑ Guerra, A., Gonzalez, A.F., Pascual, S. and Dawe, E.G. 2011. The giant squid Architeuthis: An emblematic invertebrate that can represent concern for the conservation of marine biodiversity. Biol. Conserv. 144: 1989–1997
- ↑ Engas, A. and Lokkeborg, S. 2002. Effects of seismic shooting and vessel-generated noise on fish behaviour and catch rates. Bioacoustics 12: 313–316
- ↑ Celi, M., Filiciotto, F., Vazzana, M., Arizza, V., Maccarrone, V., Ceraulo, M., Mazzola, S. and Buscaino, G. 2014. Shipping noise affecting immune responses of European spiny lobster (Palinurus elephas). Can. J. Zool. 93: 113–121
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