RESEARCH ARTICLE Soundpeaking – Hydropeaking induced changes in river soundscapes A.E. Lumsdon 1,2 | I. Artamonov 3 | M.C. Bruno 4 | M. Righetti 5 | K. Tockner 1,2† | D. Tonolla 6 | C. Zarfl 7 1 Leibniz‐Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany 2 Department of Biology, Chemistry and Pharmacy, Freie Universität Berlin, Berlin, Germany 3 Microflown Maritime B.V, Arnhem, The Netherlands 4 Fondazione Edmund Mach, IASMA Research and Innovation Centre, San Michele all'Adige, Italy 5 Department of Civil and Environmental Engineering, University of Trento, Trento, Italy 6 Institute of Natural Resource Sciences, Zurich University of Applied Sciences, Winterthur, Switzerland 7 Center for Applied Geosciences, Universität Tübingen, Tübingen, Germany Correspondence Alexander Edward Lumsdon, Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Müggelseedamm 310, Berlin 12587, Germany. Email: alex_lumsdon@hotmail.com Present Address † Austrian Science Fund (FWF), Sensengasse 1, 1090 Vienna, Austria Funding information EACEA Abstract Underwater soundscapes and their unique acoustic signatures are mainly generated through movement of streambed sediment, subsequent particle collisions, and turbulence created by water flowing over submerged obstructions such as rocks and woody debris. This study characterized river soundscapes in Alpine rivers of Trentino, (North East Italy) with the combined use of hydrophones and a new microelectricalmechanical systems based device (Hydroflown) that is capable of measuring particle velocity components of the sound field. Pool and riffle habitats affected and unaffected by hydropeaking were characterized in terms of their particle velocity and sound pressure levels across 10 octave bands (acoustic signature) to assess temporal variations in overall sound levels, changes in frequency composition, and relationship to hydromorphological habitat parameters. Data revealed that soundscapes affected by hydropeaking are highly homogenized, and sound pressure levels are strongly correlated with turbine discharge, which results in rapid, multiple‐fold spikes in low frequency amplitude levels within the typical hearing range of common teleost fish species. The outcomes of this study provide the basis for further examination of the resulting behavioural and physiological responses of organisms to anthropogenic changes in river soundscapes. KEYWORDS bioacoustics, ecohydrology, hydroacoustics, hydropower, river habitat, underwater acoustic, underwater noise 1 | INTRODUCTION Soundscapes are composed of biological (biophony), geophysical (geophony), and anthropogenic (anthrophony) sounds and create unique patterns that can be used to assess environmental conditions and biological diversity in a non‐invasive way (Pijanowski, Farina, Gage, Dumyahn, & Krause, 2011; Sueur, Pavoine, Hamerlynck, & Duvail, 2008). Underwater river soundscapes are generated by two principal sources: through the movement of streambed sediment and associated particle collisions and/or through turbulence generated by the flow of water over submerged obstructions such as bedrock outcrops, boulders, or bars (Tonolla, Lorang, Heutschi, Gotschalk, & Tockner, 2011; Tonolla, Lorang, Heutschi, & Tockner, 2009). Consequently, common river habitat types, as well as spatial habitat organization along river corridors, can be distinguished by unique acoustic signatures (Tonolla, Acuña, Lorang, Heutschi, & Tockner, 2010). Sounds are generated by a mechanical disturbance in a medium (air or water). As a sound propagates away from a source, it can be characterized by two components: sound pressure and acoustic parti- cle motion (Hawkins, 1986). Sound pressure, which is the difference between the instantaneous total pressure and the “equilibrium” pressure (which would exist in the absence of sound waves), is most easily and frequently measured in aquatic systems (Lepper, Robinson, Humphrey, & Butler, 2014). Acoustic particle motion, which is more important for organisms but rarely measured by aquatic scientists (but see e.g., Lugli & Fine, 2007; Wysocki, Codarin, Ladich, & Picciulin, Received: 12 August 2016 Revised: 13 June 2017 Accepted: 1 September 2017 DOI: 10.1002/rra.3229 River Res Applic. 2018;34:3–12. Copyright © 2017 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/rra 3