Biological contributions to the soundscape at the Main Endeavour and Lucky Strike hydrothermal vent fields

Deep sea hydrothermal vents host unique marine life adapted to survive in the high-temperature, caustic environment created by the geothermally heated vent fluid expelled from the seafloor. Some of these organisms produce sound, and it has been hypothesized that some may also use sound produced by hydrothermal vents as a cue for habitat settlement. Thus, an understanding of the acoustic environment at hydrothermal vent fields and the biological contribution to the soundscape is a critical component of an effective environmental monitoring strategy. Hydrophone measurements at the Main Endeavour vent field (MEF, from Ocean Networks Canada’s NEPTUNE observatory) and the Lucky Strike hydrothermal vent field (from the European Multidisciplinary Seafloor and water column Observatory) were analyzed to detect and quantify transient acoustic signals, which may be of biological origin. Potential source mechanisms are hypothesized, and comparisons are made between contemporaneous video and audio recordings at MEF to aid in source identification. These biological signals are also presented in the context of the broader soundscape at both sites. Implications to the establishment of baseline acoustic conditions at hydrothermal vent fields and environmental monitoring are discussed.