Main supervisor: Philippe Blondel, Physics
Second supervisor: Alan Hunter, Mechanical Engineering
Can we design acoustic techniques to measure subtle changes in marine environments? The Anthropocene is associated to strong effects on the environment from human activities and climate change, particularly underwater. Natural processes (e.g. wind, rain), biological organisms (e.g. mammals, fish) and anthropogenic activities (e.g. shipping, seismic exploration, offshore construction) all emit underwater sound, at different levels and over broad frequency ranges. These environments are changing rapidly. Human impacts are increasing at a fast rate, with more and larger commercial shipping, expanding or new shipping lanes like the Northwest Passage, intensifying marine construction etc. Marine animal species migrate to new ranges, to adapt to these activities and/or to follow climate variations. Ocean warming and acidification change how sound propagates and attenuates, but variations at more local scales are often not well constrained or monitored.
Strongly Physics-oriented, this project will combine signal processing, acoustic simulations and validations with real measurements acquired around the world. In a first stage, existing long-term datasets will be analysed using acoustic metrics designed in a previous PhD [1-2] and now recommended by national and national organisms (e.g. European Marine Strategy Framework Directive recommendations for underwater noise), Long-term variations will be assessed and compared with other data (e.g. from ocean temperatures or shipping levels), and new techniques based on polyspectral and multi-fractal approaches will be developed. Computer simulations using state-of-the-art, benchmarked software will be coupled with ensemble-averaging to quantify potential changes as the oceans warm and acidify. The research will take place in a strongly international setting.
This PhD project will take place within the Remote Sensing Group in the Department of Physics at the University of Bath. Our team is internationally recognised as being at the forefront of underwater acoustic remote sensing and connected to different groups around the world, exchanging personnel and sharing research projects. We possess experimental facilities for controlled experiments, and the simulation part of the project will use state-of-the-art software, which we have used in academic and industrial projects. We are part of the Centre for Space, Atmospheric and Oceanic Sciences (http://www.bath.ac.uk/csaos
), a cross-faculty research centre joint with the Department of Electrical Engineering, and of the Institute for Sustainable Energy and the Environment (http://www.bath.ac.uk/i-see
). The main supervisor is a Fellow of the Institute of Acoustics, and active member of British Standards committee EH/1/7 “Underwater Acoustics”, ensuring a direct link of these research activities with industry uptake and international regulations.
Acoustics is highly inter-disciplinary and this project will make full use of the richness of the field. Collaborations with different groups around the University will provide on-the-job training with engineers (Mechanical Engineering and CSAOS) and biosciences (I-SEE). Collaborations with national and international partners will offer the possibility of site visits and even field opportunities. The PhD candidate will also be strongly encouraged to use existing training opportunities at the University of Bath, available for free.
 Merchant, N.D., K.M. Fristrup, M.P. Johnson, P.L. Tyack, M.J. Witt, Ph. Blondel, S.E. Parks; “Measuring acoustic habitats”, Methods in Ecology and Evolution, 6(3):25-265, 2015
 Merchant, N.D., Ph. Blondel, D.T. Dakin, J. Dorocicz; “Averaging underwater noise levels for environmental assessment of shipping”, J. Acoust. Soc. Am., 132(4): EL343-EL349, 2012