Underwater Sounds

The MOO's audio feed was available continuously for personnel at McMurdo Station, and was occasionally broadcast live to the internet. The huge volume of recorded audio data is being archived at McMurdo Station for future transport to our U.S. research institutions for in-depth analysis. These collected data (samples of which are available at right) will become the first multi-year record of the underwater soundscape in one of the southernmost marine environments in the world.

With this aspect of the MOO project, we aim to document the bioacoustic (animal sound) signatures that reveal the presence and abundance of marine mammals that reside in or visit McMurdo Sound each year. By following changes in the types and frequency of the various calls of the resident Weddell seals, for example, we expect to contribute to an understanding of how the behavior of these southernmost marine mammals changes throughout the year.

Furthermore, by teasing apart the acoustic spectrum, analyses of the recorded data may also reveal how invertebrate animal activities vary over time. And, by listening to its creaks, cracks and groans, how the character of the sea ice cover changes as it forms, melts, and breaks up each year.  

WATCH AND LISTEN - Many marine mammal calls are distinct enough that they can be used to identify the vocalizing individuals to the species level, or even discern between different sub-species or family groups within a species.

In addition to listening directly to bioacoustic (animal sound) recordings, scientists often create spectrograms of the recorded audio data. These graphical representations of how sound frequencies change over time allow visualization of patterns in the recorded audio, recognition of sounds at much higher frequencies than humans can hear and, given distinct shapes and patterns, rapid identification of marine animal presence and activities. We will use these spectrograms, along with number of sophisticated tools that can process and automatically identify marine mammals species based on their calls, to gain new insight into McMurdo Sound's unique biology. 

In our live data viewer at McMurdo Station, a spectrogram of the current sounds recorded by the MOO scrolled continuously across the page. While it is currently not possible to transmit live audio to the world over McMurdo Station's limited satellite internet connection, MOO project staff were able to watch the spectrogram data on their computers at home as it came in. This allowed us to find, download and analyze portions of interesting or exciting sounds only a few minutes after they occur beneath the ice thousands of miles away.

FOR YOUR LISTENING PLEASURE - We have prepared a number of audio samples with accompanying spectrograms for your listening and viewing enjoyment. In these playable audio spectrograms (linked near the top of this page and below) the vertical axis represents the sound frequency (higher up means higher pitch), the horizontal axis represents time, and the color represents the intensity of the sound.

Close your eyes and imagine that you're floating beneath McMurdo Sound's icy ceiling as seals, whales, divers, and ice squeak, squawk, grumble and crack in your ears.