I have just returned from an Acoustical Society meeting held in New Orleans last week where I presented a paper on using natural occurring sounds and biological thresholds as a basis for an ocean noise criteria. Our proposed “metric” is simple to use and hopefully will serve as a usable template to understand how marine animal sound perception is based on sounds heard in their environment. It will also help determine the impacts of “introduced” noise from human sources.
The paper was reasonably well received, but these scientific conferences are an odd bird due to how “science” works in our culture. Contrary to the commonly held belief that science is about certainty, it is actually more about plausibility (and fundability). And while one objective of these meetings is to present new ideas and understandings, not all scientists are enthusiastic about new work that challenges or reframes the context of their own work.
Than being said, I had some great conversations with some of the best minds in the business, heard about fascinating research in other acoustical fields (e.g. bio-medical and physical acoustics), ate some fine New Orleans cuisine, and managed to hear some pretty good music.
One of the products of our work is the graph below. This graph represents average auditory thresholds of various dolphins (colored lines) on top of a set of lines derived from naturally occurring noise levels in the ocean. The dolphin data was collated from some 100 papers on marine mammal audiograms. This is the first time all of this data has been put in one place in graphic form. The correlation between the biological thresholds and the natural ocean ambient noise is fairly clear and suggests that ocean ambient noise curves could be used as a foundation to an ocean noise criteria.
I had a huge amount of help from OCR volunteers Libbie Horn (on marine mammals) and Gail Hurley (Fish) and mathematical modeling help from Tom Reuterdahl. While in New Orleans I volunteered to be on a new Acoustics Society biological standards committee, where I hope bring this work in to inform the committee work.
Thanks to everyone for your ongoing interest and support of OCR.