Ambrosine Clark

Rockpools or Rocking pools? Sensing the vibrations of coastal animals and understanding the potential effects of vibrational noise

Name: Ambrosine Clark
Primary Supervisor: Dr Louise Roberts
Year: 2
Discipline: Marine Biology
Presentation type: Poster
Project Title: Rockpools or Rocking pools? Sensing the vibrations of coastal animals and understanding the potential effects of vibrational noise

Abstract:

Characterising the substrate-borne vibrational response of a small tank in preparation for sensitivity experiments
Ambrosine Clark1, Louise Roberts1 Jack Thomson1, Gary Seiffert2 , Carl Hopkins2
1 Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, UK
2 Acoustics Research Unit, School of Architecture, University of Liverpool, UK
Given the infancy of aquatic biotremology as a research area, there are advantages of using a small tank to expose animals to controlled substrate-borne vibrations as part of sensitivity tests. This study investigated the vibrational response of a glass tank when excited on the base. When designing a tank, the bending mode frequencies for the base of an empty tank can be predicted, but empirical corrections are required for the water-filled tank which has lower mode frequencies. Sensitivity tests use sinusoidal excitation which can introduce unwanted harmonics; , these were typically 20-30dB below the excitation frequency (10Hz to 961Hz), but only 12dB below for harmonics near tank modes. Out-of-plane vibration over the base varied by up to 13dB but, because the animal occupies and moves over a small area during the test, averaging over squares reduces this variation to 7dB at most frequencies. These findings inform experimental design to improve the reliability of sensitivity tests in marine biotremology.