Underwater noise levels in UK waters
Nature Publishing Group
This is the author accepted manuscript of an open access article. The final version is available from Nature via the DOI in this record. This work is licensed under a Creative Commons Attribution 4.0 International License: http://creativecommons.org/licenses/by/4.0/
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.
N.D.M. and R.C.F. were supported by Defra project ME5222: Partnership-based Ambient Noise Monitoring for the MSFD. Northern North Sea data collection funded by Marine Scotland Science as part of ECOMMAS programme. Celtic Sea monitoring funded by PRIMaRE, SOWFIA (EU Intelligent Energy) and NERC (NE/J012319/1). Southern North Sea data provided by kind permission of EDF Energy New Nuclear Build marine studies programme.
Vol. 6, Article number: 36942
PubMed Central ID