Flow-noise and turbulence in two tidal channels

Bassett, Christopher; Thomson, Jim; Dahl, Peter H.; Polagye, Brian

doi:10.1121/1.4867360

Cited by 45 publications

(36 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inspiration may come from physical models for turbulence-generated seismic noise (Gimbert et al 2014). Ultimately, our work encourages future links of existing physical models of bubble-and turbulence-mediated sound (e.g., Manasseh et al 2008;Bassett et al 2014;Liu et al 2017) and bubble-and turbulence-mediated gas exchange (e.g., Lamont and Scott 1970;Chanson 1995;Woolf et al 2007). Overall, we see great potential in our method to improve the spatiotemporal coverage of gas exchange estimates in running waters with exciting opportunities to better constrain biogeochemical fluxes and ecological processes.…”

Section: Comments and Recommendationsmentioning

confidence: 73%

“…A,B) because high‐frequency sound is attenuated more strongly in water than in air. Under the water surface, SPLs increased with U even at frequencies around 31.5 Hz, indicating an increase in turbulence (Proudman ; Lighthill ; Bassett et al ) that was not detectable in air. Based on the laboratory insights described above, we chose SPL at 31.5 Hz (SPL 31.5 ) as a proxy of turbulence (for underwater sound), SPL at 1 kHz (SPL 1000 ) as a proxy of bubbles (for air and water sound), and the arithmetic mean SPL across all bands that showed marked shifts with U (250–4000 Hz in air, and 31.5–1000 Hz in water) as indices of k 600 (Table ).…”

Section: Assessmentmentioning

confidence: 99%

See 1 more Smart Citation

Listening to air–water gas exchange in running waters

Klaus

Geibrink

Hotchkiss

et al. 2019

Limnology & Ocean Methods

View full text Add to dashboard Cite

Air–water gas exchange velocities (k) are critical components of many biogeochemical and ecological process studies in aquatic systems. However, their high spatiotemporal variability is difficult to capture with traditional methods, especially in turbulent flow. Here, we investigate the potential of sound spectral analysis to infer k in running waters, based on the rationale that both turbulence and entrained bubbles drive gas exchange and cause a characteristic sound. We explored the relationship between k and sound spectral properties using laboratory experiments and field observations under a wide range of turbulence and bubble conditions. We estimated k using flux chamber measurements of CO2 exchange and recorded sound above and below the water surface by microphones and hydrophones, respectively. We found a strong influence of turbulence and bubbles on sound pressure levels (SPLs) at octave bands of 31.5 Hz and 1000 Hz, respectively. The difference in SPLs at these bands and background noise bands showed a linear correlation with k both in the laboratory (R2 = 0.93–0.99) and in the field (median R2 = 0.42–0.90). Underwater sound indices outperformed aerial sound indices in general, and indices based on hydraulic parameters in particular, in turbulent and bubbly surface flow. The results highlight the unique potential of acoustic techniques to predict k, isolate mechanisms, and improve the spatiotemporal coverage of k estimates in bubbly flow.

show abstract

Section: Comments and Recommendationsmentioning

confidence: 73%

Section: Assessmentmentioning

confidence: 99%

Listening to air–water gas exchange in running waters

Klaus

Geibrink

Hotchkiss

et al. 2019

Limnology & Ocean Methods

View full text Add to dashboard Cite

show abstract

“…More intense noise levels were observed below ~100 Hz (Fig. 2, label B), and with tidal periodicity: this is ‘pseudo-noise’ caused by turbulence around the hydrophone during tidal flow2930, and does not indicate sound present in the environment. Flow noise contamination can reduce the correlation between broadband shipping noise and the frequency bands used as anthropogenic noise indicators31, making these indicators less effective.…”

Section: Resultsmentioning

confidence: 95%

Underwater noise levels in UK waters

Merchant

Brookes

Faulkner

et al. 2016

Sci Rep

View full text Add to dashboard Cite

Underwater noise from human activities appears to be rising, with ramifications for acoustically sensitive marine organisms and the functioning of marine ecosystems. Policymakers are beginning to address the risk of ecological impact, but are constrained by a lack of data on current and historic noise levels. Here, we present the first nationally coordinated effort to quantify underwater noise levels, in support of UK policy objectives under the EU Marine Strategy Framework Directive (MSFD). Field measurements were made during 2013–2014 at twelve sites around the UK. Median noise levels ranged from 81.5–95.5 dB re 1 μPa for one-third octave bands from 63–500 Hz. Noise exposure varied considerably, with little anthropogenic influence at the Celtic Sea site, to several North Sea sites with persistent vessel noise. Comparison of acoustic metrics found that the RMS level (conventionally used to represent the mean) was highly skewed by outliers, exceeding the 97th percentile at some frequencies. We conclude that environmental indicators of anthropogenic noise should instead use percentiles, to ensure statistical robustness. Power analysis indicated that at least three decades of continuous monitoring would be required to detect trends of similar magnitude to historic rises in noise levels observed in the Northeast Pacific.

show abstract

“…In this case, the current speed seemed to follow the tidal cycle quite closely, given the low tidal range (±0.5 m), and we suspect that the flow of water over the hydrophone was limited. In other systems, current can be correlated with the noise of water running over a hydrophone (flow noise) (Haxel et al 2013;Bassett et al 2014). Although not measured for this study, we suspect that increased SPL at one of our sites (Channel) could be related to increased flow because this site was deeper than all other sites and appeared to have a faster current.…”

Section: Geophonymentioning

confidence: 90%

The summer soundscape of a shallow-water estuary used by beluga whales in the western Canadian Arctic

et al. 2020

View full text Add to dashboard Cite

The soundscape is an important habitat component for marine animals. In the Arctic, marine conditions are changing rapidly due to sea ice loss and increased anthropogenic activities such as shipping, which will influence the soundscape. Here, we assess the contributors to the summer soundscape in the shallow waters of the Mackenzie River estuary within the Tarium Niryutait Marine Protected Area in the western Canadian Arctic, a core summering habitat for beluga whales (Delphinapterus leucas Pallas, 1776). We collected passive acoustic data during the summer over four years, and assessed the influence of physical variables, beluga whale vocalizations, and boat noise on sound pressure levels in three frequency bands (low: 0.2-1 kHz; medium: 1-10 kHz; high: 10-48 kHz) to quantify the soundscape. Wind speed, wave height, beluga vocalizations, and boat noise were all large contributors to the soundscape in various frequency bands. The soundscape varied to a lesser degree between sites, time of day, and with tide height, but remained relatively constant between years. This study is the first detailed description of a shallow summer soundscape in the western Canadian Arctic, an important habitat for beluga whales, and can be used as a baseline to monitor future changes during this season.

show abstract

Flow-noise and turbulence in two tidal channels

Cited by 45 publications

References 35 publications

Listening to air–water gas exchange in running waters

Listening to air–water gas exchange in running waters

Underwater noise levels in UK waters

The summer soundscape of a shallow-water estuary used by beluga whales in the western Canadian Arctic

Contact Info

Product

Resources

About