Abstract:This paper analyzes an 8-month time series (November 2005 to June 2006) of underwater noise recorded at the mouth of the Amundsen Gulf in the marginal ice zone of the western Canadian Arctic when the area was >90% ice covered. The time-series of the ambient noise component was computed using an algorithm that filtered out transient acoustic events from 7-min hourly recordings of total ocean noise over a [0-4.1] kHz frequency band. Under-ice ambient noise did not respond to thermal changes, but showed consisten… Show more
“…rain, current flow, wind-driven waves) partially or completely masks even the loudest of biological signals ([ 104 , 130 ], figure 2 ). Other geophysical sounds such as ice-generated noise can be seasonally persistent, high amplitude and similar to biological sounds [ 131 , 132 ], making it easy to detect but difficult to distinguish from biological sounds.…”
Section: Considerations For Using Acoustic Methods To Estimate Marinementioning
confidence: 99%
“…Perhaps one way to use LTSA processing to address these rare sounds leverages the ‘constraint’ that many marine soundscapes have, a predominance of lower-frequency sounds and thus non-Gaussian and right-skewed distribution of power spectral densities (PSDs). The difference between the mean and median or the background ambient noise PSDs can be effective to reduce the influence of continuous signals and thus enhance the presence of transient signals [ 131 , 207 ] ( figure 4 ). Figure 4.…”
Section: Current Methods Supporting Acoustic Diversity Assessmentsmentioning
Ecosystems and the communities they support are changing at alarmingly rapid rates. Tracking species diversity is vital to managing these stressed habitats. Yet, quantifying and monitoring biodiversity is often challenging, especially in ocean habitats. Given that many animals make sounds, these cues travel efficiently under water, and emerging technologies are increasingly cost-effective, passive acoustics (a long-standing ocean observation method) is now a potential means of quantifying and monitoring marine biodiversity. Properly applying acoustics for biodiversity assessments is vital. Our goal here is to provide a timely consideration of emerging methods using passive acoustics to measure marine biodiversity. We provide a summary of the brief history of using passive acoustics to assess marine biodiversity and community structure, a critical assessment of the challenges faced, and outline recommended practices and considerations for acoustic biodiversity measurements. We focused on temperate and tropical seas, where much of the acoustic biodiversity work has been conducted. Overall, we suggest a cautious approach to applying current acoustic indices to assess marine biodiversity. Key needs are preliminary data and sampling sufficiently to capture the patterns and variability of a habitat. Yet with new analytical tools including source separation and supervised machine learning, there is substantial promise in marine acoustic diversity assessment methods.
“…rain, current flow, wind-driven waves) partially or completely masks even the loudest of biological signals ([ 104 , 130 ], figure 2 ). Other geophysical sounds such as ice-generated noise can be seasonally persistent, high amplitude and similar to biological sounds [ 131 , 132 ], making it easy to detect but difficult to distinguish from biological sounds.…”
Section: Considerations For Using Acoustic Methods To Estimate Marinementioning
confidence: 99%
“…Perhaps one way to use LTSA processing to address these rare sounds leverages the ‘constraint’ that many marine soundscapes have, a predominance of lower-frequency sounds and thus non-Gaussian and right-skewed distribution of power spectral densities (PSDs). The difference between the mean and median or the background ambient noise PSDs can be effective to reduce the influence of continuous signals and thus enhance the presence of transient signals [ 131 , 207 ] ( figure 4 ). Figure 4.…”
Section: Current Methods Supporting Acoustic Diversity Assessmentsmentioning
Ecosystems and the communities they support are changing at alarmingly rapid rates. Tracking species diversity is vital to managing these stressed habitats. Yet, quantifying and monitoring biodiversity is often challenging, especially in ocean habitats. Given that many animals make sounds, these cues travel efficiently under water, and emerging technologies are increasingly cost-effective, passive acoustics (a long-standing ocean observation method) is now a potential means of quantifying and monitoring marine biodiversity. Properly applying acoustics for biodiversity assessments is vital. Our goal here is to provide a timely consideration of emerging methods using passive acoustics to measure marine biodiversity. We provide a summary of the brief history of using passive acoustics to assess marine biodiversity and community structure, a critical assessment of the challenges faced, and outline recommended practices and considerations for acoustic biodiversity measurements. We focused on temperate and tropical seas, where much of the acoustic biodiversity work has been conducted. Overall, we suggest a cautious approach to applying current acoustic indices to assess marine biodiversity. Key needs are preliminary data and sampling sufficiently to capture the patterns and variability of a habitat. Yet with new analytical tools including source separation and supervised machine learning, there is substantial promise in marine acoustic diversity assessment methods.
“…Throughout the Arctic, belugas have adapted to a complex soundscape. The Arctic is one of the quietest places on earth under solid sea ice (Diachok and Winokur 1974;Roth et al 2012;Insley et al 2017), but it can be extremely noisy when ice is forming and breaking up (Diachok and Winokur 1974;Roth et al 2012;Kinda et al 2013Kinda et al , 2015Insley et al 2017), during storm events (Roth et al 2012;Insley et al 2017), or around calving glaciers (Deane et al 2014). In contrast to other cetaceans that occur in temperate or tropical latitudes, belugas in the Arctic currently deal with very low levels of anthropogenic noise; however, climate change will likely result in a changing soundscape (Moore et al 2012).…”
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.
“…It is composed of natural abiotic ambient sounds (geophony; Kinda et al 2013, Mathias et al 2016, anthropogenic sounds (anthrophony; Hildebrand 2009) and sounds from marine fauna (biophony). The main contributors to biophony are cetaceans (Au & Hastings 2008), fishes (Amorim 2006, Rountree et al 2006, Luczkovich et al 2008) and benthic invertebrates (Patek 2001, Popper et al 2001, Coquereau et al 2016a).…”
Coastal soundscapes are dominated by broadband transient sounds primarily emitted by benthic invertebrates. These sounds are characterized by a very large dynamic of amplitude. The loudest ones propagate further and interfere with the detectability of benthic sounds by invading other more distant habitats. Acoustic diversity assessment is therefore biased when applying acoustic indices related to the signal's power. Here, we propose new acoustic indices (IDSS: indices of the diversity of spectral shape) capable of extracting the diversity of the benthic invertebrate biophony (BIB) despite interference from loud and abundant sounds. A passive acoustic ecological survey was conducted in a shallow Mediterranean bay with a small-scale mosaic of biocenosis. The sound pressure level and spectrum of the BIB revealed that the rocky fringe had the most powerful biophony, propagating up to 3680 m, thus 'invading' other habitats. However, these power-based indices failed to depict BIB diversity. The IDSS allowed us to discriminate BIB diversity despite the interfering rocky fringe biophony, including low-power sounds not depicted by traditional power-based methods. Four main categories of benthic invertebrates sounds (BIS) spectra were found. Two categories (high-power, peak frequencies ~3 to 4 kHz) were mainly linked to the rocky fringe. Their contribution to the diversity (56%) decreased with increasing distance to the fringe, where low-power BIS (peak frequencies above 15 kHz) predominantly contributed to the BIB (42%) and may be specific to coralligenous reefs. The IDSS enables a better characterization and quantification of BIB diversity and soundscape structure with a fine spatial resolution (~200 m).
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