Soundscape and ambient noise levels of the Arctic waters around Greenland

Michael Ladegaard,Peter Teglberg Madsen,Malene Simon,Michael Bjerre Pedersen,Aleksandrina Mitseva,Jamie Macaulay,Jakob Tougaard,Simone Videsen,Kristin L Laidre

doi:10.1038/s41598-021-02255-6

Michael Ladegaard, Peter Teglberg Madsen + Show 7 more

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https://doi.org/10.1038/s41598-021-02255-6

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A longer Arctic open water season is expected to increase underwater noise levels due to anthropogenic activities such as shipping, seismic surveys, sonar, and construction. Many Arctic marine mammal species depend on sound for communication, navigation, and foraging, therefore quantifying underwater noise levels is critical for documenting change and providing input to management and legislation. Here we present long-term underwater sound recordings from 26 deployments around Greenland from 2011 to 2020. Ambient noise was analysed in third octave and decade bands and further investigated using generic detectors searching for tonal and transient sounds. Ambient noise levels partly overlap with previous Arctic observations, however we report much lower noise levels than previously documented, specifically for Melville Bay and the Greenland Sea. Consistent seasonal noise patterns occur in Melville Bay, Baffin Bay and Greenland Sea, with noise levels peaking in late summer and autumn correlating with open water periods and seismic surveys. These three regions also had similar tonal detection patterns that peaked in May/June, likely due to bearded seal vocalisations. Biological activity was more readily identified using detectors rather than band levels. We encourage additional research to quantify proportional noise contributions from geophysical, biological, and anthropogenic sources in Arctic waters.

Highlights

A longer Arctic open water season is expected to increase underwater noise levels due to anthropogenic activities such as shipping, seismic surveys, sonar, and construction
The ambient noise was computed as third octave levels (TOLs) and summarised as decade levels (Fig. 2) for the decade bands at 10–100 Hz, 100–1000 Hz, and 1–10 kHz
The “Supplementary Information” contain TOL distribution plots for each deployment and monthly TOLs summarised in tables as exceedance levels ( L1, L5, L10, L25, L50, L75, L90, L95, and L 99) for each of the 26 stations

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A longer Arctic open water season is expected to increase underwater noise levels due to anthropogenic activities such as shipping, seismic surveys, sonar, and construction. Underwater noise levels are on the rise globally due to human activities such as shipping, seismic surveys, sonar, and construction[5] and are predicted to continue to increase in the future[6]. Paramount to managing any environmental pressure factor, such as underwater noise, is the ability to monitor its development in time and space Such monitoring can inform managers of the magnitude of the problem, the relative contribution of individual sources and, most importantly, provide feedback on the effectiveness of mitigation measures. It is critical to establish sufficient acoustic monitoring in the Arctic to track the predicted changes in ambient noise levels and allow for mitigation and legislation development on an informed b asis[14,17,18]

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