Down‐slope enhancement models for low‐frequency ocean noise and propagation

1978 ◽  
Vol 64 (S1) ◽  
pp. S46-S46
Author(s):  
J. Northrop ◽  
R. A. Wagstaff
Keyword(s):  
Low Frequency ◽  
Ocean Noise

scholarly journals A key to quieter seas: half of ship noise comes from 15% of the fleet

2018 ◽  
Author(s):  
Scott Veirs ◽  
Val Veirs ◽  
Rob Williams ◽  
Michael Jasny ◽  
Jason Wood
Keyword(s):  
Low Frequency ◽  
Noise Pollution ◽  
Marine Species ◽  
International Maritime Organization ◽  
Total Power ◽  
Underwater Noise ◽  
Noise Levels ◽  
Management Options ◽  
Ocean Noise ◽  
Wide Range

Underwater noise pollution from ships is a chronic, global stressor impacting a wide range of marine species. Ambient ocean noise levels nearly doubled each decade from 1963-2007 in low-frequency bands attributed to shipping, inspiring a pledge from the International Maritime Organization to reduce ship noise and a call from the International Whaling Commission for member nations to halve ship noise within a decade. Our analysis of data from 1,582 ships reveals that half of the total power radiated by a modern fleet comes from just 15% of the ships, namely those with source levels above 179 dB re 1 μPa @ 1 m. We present a range of management options for reducing ship noise efficiently, including incentive-based programs, without necessarily regulating the entire fleet.

scholarly journals A key to quieter seas: half of ship noise comes from 15% of the fleet

2018 ◽  
Author(s):  
Scott Veirs ◽  
Val Veirs ◽  
Rob Williams ◽  
Michael Jasny ◽  
Jason Wood
Keyword(s):  
Low Frequency ◽  
Noise Pollution ◽  
Marine Species ◽  
International Maritime Organization ◽  
Total Power ◽  
Underwater Noise ◽  
Noise Levels ◽  
Management Options ◽  
Ocean Noise ◽  
Wide Range

Underwater noise pollution from ships is a chronic, global stressor impacting a wide range of marine species. Ambient ocean noise levels nearly doubled each decade from 1963-2007 in low-frequency bands attributed to shipping, inspiring a pledge from the International Maritime Organization to reduce ship noise and a call from the International Whaling Commission for member nations to halve ship noise within a decade. Our analysis of data from 1,582 ships reveals that half of the total power radiated by a modern fleet comes from just 15% of the ships, namely those with source levels above 179 dB re 1 μPa @ 1 m. We present a range of management options for reducing ship noise efficiently, including incentive-based programs, without necessarily regulating the entire fleet.

scholarly journals Seagrass Posidonia is impaired by human-generated noise

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Marta Solé ◽  
Marc Lenoir ◽  
Mercè Durfort ◽  
José-Manuel Fortuño ◽  
Mike van der Schaar ◽  
...  
Keyword(s):  
Low Frequency ◽  
Noise Pollution ◽  
Biodiversity Loss ◽  
Posidonia Oceanica ◽  
Vital Role ◽  
Ultrastructural Changes ◽  
Artificial Noise ◽  
Ocean Noise ◽  
Many Sources ◽  
Sound Vibration

AbstractThe last hundred years have seen the introduction of many sources of artificial noise in the sea environment which have shown to negatively affect marine organisms. Little attention has been devoted to how much this noise could affect sessile organisms. Here, we report morphological and ultrastructural changes in seagrass, after exposure to sounds in a controlled environment. These results are new to aquatic plants pathology. Low-frequency sounds produced alterations in Posidonia oceanica root and rhizome statocysts, which sense gravity and process sound vibration. Nutritional processes of the plant were affected as well: we observed a decrease in the number of rhizome starch grains, which have a vital role in energy storage, as well as a degradation in the specific fungal symbionts of P. oceanica roots. This sensitivity to artificial sounds revealed how sound can potentially affect the health status of P. oceanica. Moreover, these findings address the question of how much the increase of ocean noise pollution may contribute in the future to the depletion of seagrass populations and to biodiversity loss.

scholarly journals Singing whales generate high levels of particle motion: implications for acoustic communication and hearing?

2016 ◽  
Vol 12 (11) ◽  
pp. 20160381 ◽  
Author(s):  
T. Aran Mooney ◽  
Maxwell B. Kaplan ◽  
Marc O. Lammers
Keyword(s):  
Particle Velocity ◽  
Acoustic Communication ◽  
Particle Motion ◽  
Animal Communication ◽  
Bone Conduction ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Humpback Whales ◽  
Communication Signals ◽  
Ocean Noise

Acoustic signals are fundamental to animal communication, and cetaceans are often considered bioacoustic specialists. Nearly all studies of their acoustic communication focus on sound pressure measurements, overlooking the particle motion components of their communication signals. Here we characterized the levels of acoustic particle velocity (and pressure) of song produced by humpback whales. We demonstrate that whales generate acoustic fields that include significant particle velocity components that are detectable over relatively long distances sufficient to play a role in acoustic communication. We show that these signals attenuate predictably in a manner similar to pressure and that direct particle velocity measurements can provide bearings to singing whales. Whales could potentially use such information to determine the distance of signalling animals. Additionally, the vibratory nature of particle velocity may stimulate bone conduction, a hearing modality found in other low-frequency specialized mammals, offering a parsimonious mechanism of acoustic energy transduction into the massive ossicles of whale ears. With substantial concerns regarding the effects of increasing anthropogenic ocean noise and major uncertainties surrounding mysticete hearing, these results highlight both an unexplored pathway that may be available for whale acoustic communication and the need to better understand the biological role of acoustic particle motion.

scholarly journals Measurement of Low-Frequency Ocean Noise by a Self-Recording Hydrophone

2007 ◽  
Vol 29 (4) ◽  
pp. 311-316
Author(s):  
Bong-Chae Kim ◽  
Byoung-Nam Kim ◽  
Hong-Sang Cho
Keyword(s):  
Low Frequency ◽  
Ocean Noise

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

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