As a research assistant, I do a lot of data analysis for our group. I’ve been learning a lot about the different under ocean sounds we come across and how to find them on a spectrogram to help answer questions that our scientists put forth, but I’ve still got much to learn. I spent years picking out earthquakes and volcanic tremor in the Lau Basin (a very active area under the ocean near Fiji). I was so focused on locating earthquake and volcanic activity for that project, that I pretty much ignored any other random noises. When picking out earthquakes and volcanic tremor, you have to set your scrolling of the spectrograms (spectrograms are pictures of the sounds on a time and frequency view) in a way that you can get through data at a quicker pace and pay attention to the louder events. My screen for looking at earthquake and volcanic activity encompassed 15 or 20 minutes of data in one screen and scrolled fairly quickly. For quieter sounds, like some marine mammals, and especially fish, you are looking at about 1 minute of data per screen and the going is a lot slower!
We have scientists who have developed software to help automatically detect certain sounds in the data we collect. This doesn’t work for every type of sound and has varying degrees of accuracy, depending on other sounds present that may be in the same frequency range. Next up, I’ll be learning about one of these programs called Ishmael (developed by Dr. David Mellinger – he’s on our People Page) and, with the help of Sara Heimlich (also on our People Page), seeing if it can do a good job picking out orca sounds right off of South Beach here in Newport. I have found many of these orca sounds manually, but at 1 minute of data per screen, it would be very time consuming to go through all of the data that way. Check back later, and I’ll let you know how the automatic detection software does.
Noise in the ocean has become a hot topic lately in the media. (It’s incredible just how loud ship noise can be. Even louder: icebergs grounding and calving). How does man-made and other noise in the ocean affect fish, or marine mammals who depend on sound to navigate, hunt, find food, or communicate? These are questions scientists are busy trying to answer. VIBES, our new group acronym, stands for Volcanic, Ice, Biological, and Earthquake Sounds in the ocean. We also record surf and man-made sounds like oil drilling, ship noise, wave energy technology, and anything else you can think of down there.
Following are some examples of what I see in the data we get back from our under ocean recordings and the sounds that accompany them. Please let me know your best guess for the final sound!
(Note: sound clips for most of these encompass the data between the 2 fine white lines shown on the spectrograms, and are best heard on decent speakers or through headphones.)
