Please join us for the AOS Seminar on Wednesday, June 15th at 12:00 pm in Spiess Hall Room 330.
Speaker: Simon Freeman, Naval Research Laboratory
"Snapshots with sound: Rapidly obtained ecological status indicators in coral reef soundscapes"
Rapid coral reef ecosystem monitoring techniques can be costly, labor-intensive point measurements that introduce intractable sampling bias and error. Passive acoustic monitoring holds promise, but the task of identifying individual soundscape contributors requires sophisticated equipment and validation. An argument can be made for more holistic techniques that use data more readily available to monitoring agencies. I will report on correlations between visually obtained ecological assessment metrics and short-term, concurrent underwater biological soundscape recordings over reefs throughout the Hawaiian Islands. Sites grouped along a principal component defined by an acoustic ‘sliding scale’: from protected and/or remote sites at which lower frequencies were more dominant, to degraded sites which produced soundscapes dominated by higher frequencies. Positive correlations between biological sounds below 2 kHz and the density of benthic invertebrates, their predators, bathymetric complexity and crustose coralline algae cover suggest a connection between lower frequencies, benthic habitat complexity and faunal density. Also observed was a correlation between daytime soundscape components between 2-20 kHz and fleshy macroalgal cover, an indicator of reef degradation. These results suggest that while individual soundscape contributors are not specifically defined, holistic, rapid and spatially integrative remote sensing of reef ecological state is feasible. This type of capability could enhance the remote detection of subtle but pervasive ecological changes brought about by climate change and other more localized anthropogenic impacts.
Part 2: "Strategy Post-PhD: My take on how to make an underwater acoustics postdoc work for you"