The coastal Arctic marine soundscape near Ulukhaktok, Northwest Territories, Canada

The Arctic marine soundscape of the Amundsen Gulf, Western Canadian Arctic

The underwater soundscape, a habitat component for Arctic marine mammals, is shifting. We examined the drivers of the underwater soundscape at three sites in the Amundsen Gulf, Northwest Territories, Canada from 2018 to 2019 and estimated the contribution of abiotic and biotic sources between 20 Hz and 24 kHz. Higher wind speeds and the presence of bearded seal (Erignathus barbatus) vocalizations led to increased SPL (0.41 dB/km/h and 3.87 dB, respectively), while higher ice concentration and air temperature led to decreased SPL (-0.39 dB/% and - 0.096 dB/°C, respectively). Other marine mammals did not significantly impact the ambient soundscape. The presence of vessel traffic led to increased SPLs (12.37 dB) but was quieter at distances farther from the recorder (-2.57 dB/log m). The presence of high frequency and broadband signals produced by ice led to increased SPLs (7.60 dB and 10.16 dB, respectively).

Opportunistic ship source level measurements in the Western Canadian Arctica)

Increased ship traffic due to climate change increases underwater noise in the Arctic. Therefore, accurate measurements of underwater radiated noise are necessary to map marine sound and quantify shipping's impact on the Arctic ecosystem. This paper presents a method to calculate opportunistic source levels (SLs) using passive acoustic data collected at six locations in the Western Canadian Arctic from 2018 to 2022. Based on Automatic Identification System data, acoustic data, and a hybrid sound propagation model, the SLs of individual ships were calculated within a 5 km radius of each measurement site. A total of 66 measurements were obtained from 11 unique vessels, with multiple measurements from the same vessel type contributing more SLs. For vessels with propeller cavitation, measured SLs correlated positively with vessel parameters, such as speed and length. SL and speed did not correlate well for vessels without propeller cavitation. The JOMOPANS-ECHO SL model produced good agreement with measured SL for certain ship types (container ships, a tanker, and a passenger vessel). However, significant differences between measurement and model are evident for certain polar-class ships that travel in the Arctic, indicating that more controlled SL measurements are needed.

Impact of ship noise on the underwater soundscape of Eclipse Sound in the northeastern Canadian Arctic

Eclipse Sound, in the northeastern Canadian Arctic, has experienced a substantial increase in ship traffic due to growing tourism and industrial development in the region. This study aims to describe the natural soundscape as well as to assess the noise levels associated with shipping. Underwater sound recordings were collected at two locations: Eastern Eclipse Sound (72° 43.730 N, 76° 13.519 W, 670 m) leading to Baffin Bay, and Milne Inlet (72° 15.260 N, 80° 34.205 W, 313 m) situated near the southwest end of Eclipse Sound. To capture the dynamic nature of the soundscape, the data from these two locations were divided into three seasons: late spring, summer, and early fall. These periods were selected to account for the changing contribution of sea ice to the soundscape during the sea ice break-up, two months of open water, and the sea ice freeze-up. By analyzing ship tracks and underwater acoustic recordings, we identified patterns of ship traffic and estimated underwater noise levels due to ships. Noise emitted by ships is quantified by vessel type, including three cargo ship types, passenger ships, pleasure craft, and icebreakers. Individual ship transits through the region introduce transient noise at frequencies from <20 Hz to >20 kHz, with durations lasting from a few minutes to >6 h. The impact of ship noise on the soundscape is significant, resulting in increases in sound levels by 15 to >30 dB when ships are within 10 km and measurable ship noise below 200 Hz at distances of >50 km.

Ocean ambient noise on the Chukchi Plateau and its environmental correlates

Conducting research on ocean ambient noise under different sea ice conditions is highly important for the comprehension of the rapidly changing Arctic. We present the first results of ambient noise and its relationship to environmental forcing during the open-water, ice transition and ice-covered periods on the Chukchi Plateau. The ambient noise level (ANL) in the 20 Hz to 2 kHz band is higher, intermediate and lower during the open-water, ice transition and ice-covered periods, respectively. During the ice-covered period, the ambient noise is dominated by the ice-generated noise due to sea ice activities and shows a negative correlation with temperature. Therefore, when the temperature decreases, the sea ice is prone to shrinking and cracking, thus increasing the sea ice activities and resulting in increased ice-generated noise; when the temperature rises and is relatively high in May and June, the ANL is lowest for the sea ice inhibition to wind waves and decreased sea ice activities induced by temperature rise. Sea ice is the most predominant environmental factor affecting Arctic ocean ambient noise, and the ANL can potentially increase due to a reduction in Arctic sea ice and increase in human activities caused by global climate change.

Temporal patterns in the soundscape of a Norwegian gateway to the Arctic

As an Arctic gateway, the Norwegian Sea sustains a rich diversity of seasonal and resident species of soniferous animals, vulnerable to the effects of climate change and anthropogenic activities. We show the occurrence of seasonal patterns of acoustic signals in a small canyon off Northern Norway, and investigate cetacean vocal behavior, human-made noise, and climatic contributions to underwater sound between January and May 2018. Mostly median sound levels ranged between 68.3 and 96.31 dB re 1 μPa2 across 1/3 octave bands (13 Hz-16 kHz), with peaks in February and March. Frequencies under 2 kHz were dominated by sounds from baleen whales with highest rates of occurrence during winter and early spring. During late-spring non-biological sounds were predominant at higher frequencies that were linked mainly to ship traffic. Seismic pulses were also recorded during spring. We observed a significant effect of wind speed and ship sailing time on received sound levels across multiple distance ranges. Our results provide a new assessment of high-latitude continental soundscapes in the East Atlantic Ocean, useful for management strategies in areas where anthropogenic pressure is increasing. Based on the current status of the local soundscape, we propose considerations for acoustic monitoring to be included in future management plans.

Assessing potential perception of shipping noise by marine mammals in an arctic inlet

Shipping is increasing in Arctic regions, exposing marine mammals to increased underwater noise. Noise analyses often use unweighted broadband sound pressure levels (SPL) to assess noise impacts, but this does not account for the animals' hearing abilities at different frequencies. In 2018 and 2019, noise levels were recorded at five and three sites, respectively, along a shipping route in an inlet of Northern Baffin Island, Canada. Broadband SPLs (10 Hz-25 kHz), unweighted and with auditory weighing functions from three marine mammal groups, were compared between times ore carriers (travelling < 9 knots) were present or absent. Clearly audible distances of shipping noise and exposure durations were estimated for each weighting function relative to vessel direction, orientation, and year. Auditory weighting functions had significant effects on the potential perception of shipping noise. Bowhead whales (Balaena mysticetus) experienced similar SPLs to unweighted levels. Narwhals (Monodon monoceros) and ringed seals (Pusa hispida) experienced lower SPLs. Narwhals were unlikely to clearly perceive shipping noise unless ships were in close proximity (<3 km) and ambient noise levels were low. Detectability propagation models of presumed noise exposure from shipping must be based on the hearing sensitivities of each species group when assessing noise impacts on marine mammals.

Passive acoustic monitoring reveals year-round marine mammal community composition off Tasiilaq, Southeast Greenland

Climate-driven changes are affecting sea ice conditions off Tasiilaq, Southeast Greenland, with implications for marine mammal distributions. Knowledge about marine mammal presence, biodiversity, and community composition is key to effective conservation and management but is lacking, especially during winter months. Seasonal patterns of acoustic marine mammal presence were investigated relative to sea ice concentration at two recording sites between 2014 and 2018, with one (65.6°N, 37.4°W) or three years (65.5°N, 38.0°W) of passive acoustic recordings. Seven marine mammal species were recorded. Bearded seals were acoustically dominant during winter and spring, whereas sperm, humpback, and fin whales dominated during the sea ice-free summer and autumn. Narwhals, bowhead, and killer whales were recorded only rarely. Song-fragments of humpback whales and acoustic presence of fin whales in winter suggest mating-associated behavior taking place in the area. Ambient noise levels in 1/3-octave level bands (20, 63, 125, 500, 1000, and 4000 Hz), ranged between 75.6 to 105 dB re 1 μPa. This study provides multi-year insights into the coastal marine mammal community composition off Southeast Greenland and suggests that the Tasiilaq area provides suitable habitat for various marine mammal species year-round.

An integrated underwater soundscape analysis in the Bering Strait region

Rapid changes in the Arctic from shifting climate and human use patterns are affecting previously reported distributions and movements of marine mammals. The underwater soundscape, a key component of marine mammal habitats, is also changing. This study integrates acoustic data, collected at a site in the northern Bering Sea, with information on sound sources to quantify their occurrence throughout the year and identify deviations in conditions and dominant soundscape components. Predictive models are applied to explain variation in sound levels and to compare the relative contributions of various soundscape components. Levels across all octave bands were influenced most strongly by the variation in abiotic environment across seasons. The presence of commercial ships did not have a discernible effect on sound levels at this location and period of time. The occurrence of sources was compared to a second site, where we documented how higher levels of shipping changed that soundscape. This study demonstrated the value of acoustic monitoring to characterize the dominant acoustic features in a soundscape and the importance of preserving soundscapes based on dominant features rather than level of sound. Using a soundscape approach has relevance for protecting marine mammals and for the food security of Alaska Native communities that depend upon them.

Underwater sound levels in the Canadian Arctic, 2014-2019

The Arctic has been a refuge from anthropogenic underwater noise; however, climate change has caused summer sea ice to diminish, allowing for unprecedented access and the potential for increased underwater noise. Baseline underwater sound levels must be quantified to monitor future changes and manage underwater noise in the Arctic. We analyzed 39 passive acoustic datasets collected throughout the Canadian Arctic from 2014 to 2019 using statistical models to examine spatial and temporal trends in daily mean sound pressure levels (SPL) and quantify environmental and anthropogenic drivers of SPL. SPL (50-1000 Hz) ranged from 70 to 127 dB re 1 μPa (median = 91 dB). SPL increased as wind speed increased, but decreased as both ice concentration and air temperature increased, and SPL increased as the number of ships per day increased. This study provides a baseline for underwater sound levels in the Canadian Arctic and fills many geographic gaps on published underwater sound levels.

Bowhead and beluga whale acoustic detections in the western Beaufort Sea 2008-2018

The Distributed Biological Observatory (DBO) was established to detect environmental changes in the Pacific Arctic by regular monitoring of biophysical responses in each of 8 DBO regions. Here we examine the occurrence of bowhead and beluga whale vocalizations in the western Beaufort Sea acquired by acoustic instruments deployed from September 2008-July 2014 and September 2016-October 2018 to examine inter-annual variability of these Arctic endemic species in DBO Region 6. Acoustic data were collected on an oceanographic mooring deployed in the Beaufort shelfbreak jet at ~71.4°N, 152.0°W. Spectrograms of acoustic data files were visually examined for the presence or absence of known signals of bowhead and beluga whales. Weekly averages of whale occurrence were compared with outputs of zooplankton, temperature and sea ice from the BIOMAS model to determine if any of these variables influenced whale occurrence. In addition, the dates of acoustic whale passage in the spring and fall were compared to annual sea ice melt-out and freeze-up dates to examine changes in phenology. Neither bowhead nor beluga whale migration times changed significantly in spring, but bowhead whales migrated significantly later in fall from 2008-2018. There were no clear relationships between bowhead whales and the environmental variables, suggesting that the DBO 6 region is a migratory corridor, but not a feeding hotspot, for this species. Surprisingly, beluga whale acoustic presence was related to zooplankton biomass near the mooring, but this is unlikely to be a direct relationship: there are likely interactions of environmental drivers that result in higher occurrence of both modeled zooplankton and belugas in the DBO 6 region. The environmental triggers that drive the migratory phenology of the two Arctic endemic cetacean species likely extend from Bering Sea transport of heat, nutrients and plankton through the Chukchi and into the Beaufort Sea.

Bowhead whales overwinter in the Amundsen Gulf and Eastern Beaufort Sea

The bowhead whale is the only baleen whale endemic to the Arctic and is well adapted to this environment. Bowheads live near the polar ice edge for much of the year and although sea ice dynamics are not the only driver of their annual migratory movements, it likely plays a key role. Given the intrinsic variability of open water and ice, one might expect bowhead migratory plasticity to be high and linked to this proximate environmental factor. Here, through a network of underwater passive acoustic recorders, we document the first known occurrence of bowheads overwintering in what is normally their summer foraging grounds in the Amundsen Gulf and eastern Beaufort Sea. The underlying question is whether this is the leading edge of a phenological shift in a species' migratory behaviour in an environment undergoing dramatic shifts due to climate change.

ecoSound-web: an open-source, online platform for ecoacoustics

Passive acoustic monitoring of soundscapes and biodiversity produces vast amounts of audio recordings, but the management and analyses of these raw data present technical challenges. A multitude of software solutions exist, but none can fulfil all purposes required for the management, processing, navigation, analysis, and dissemination of acoustic data. The field of ecoacoustics needs a software tool that is free, evolving, and accessible. We take a step in that direction and present ecoSound-web: an open-source, online platform for ecoacoustics designed and built by ecologists and software engineers. ecoSound-web can be used for storing, organising, and sharing soundscape projects, manually creating and peer-reviewing annotations of soniferous animals and phonies, analysing audio in time and frequency, computing alpha acoustic indices, and providing reference sound libraries for different taxa. We present ecoSound-web's features, structure, and compare it with similar software. We describe its operation mode and the workflow for typical use cases such as the sampling of bird and bat communities, the use of a primate call library, and the analysis of phonies and acoustic indices. ecoSound-web is available from: https://github.com/ecomontec/ecoSound-web.