We’re all familiar with the sound of waves crashing along the beach, a calming and grounding sound that is capable of lulling people to sleep. You’ve probably also heard of ship horns, and speedboats, or if you’re into watersports, the sound of your paddle slicing through the water in a sea kayak. However, there are definitely sounds from deep under the ocean that we’ve not been privy to. I had the opportunity to dive at Pulau Hantu, off Singapore’s coasts, but even then I don’t recall hearing much while 6m underwater. If you’ve ever wondered what the sea sounds like to marine creatures, I chanced upon this resource where you can listen to the sea!
Listen to the Deep Ocean Environment (LIDO) is an international project which monitors passive acoustics within the ocean. Real-time data is processed through software, with dedicated modules for noise assessment, detection, classification, and localisation. The LIDO system takes an acoustic data stream as input and characterises the acoustic events detected in the data as output (André et al., 2011).
Try it yourself here!
How does it work?
Acoustic monitoring of cetacean distributions was initiated in the 1970s and used to track whales over large distances. With advances in electronics, Passive Acoustic Monitoring (PAM) technology is more accessible. PAMs work by isolating targeted calls from the rest of the acoustic signals (Ocean Networks Canada, 2010).
On LIDO, software developed identifies and colour-codes the different sources of sound from individual observatories all over the world,. Deep-sea observatories also pick up sounds of geological processes that are then stored in their sound library.
What about naval data?
Listening to the ocean also has historical significance – the US Navy set up an underwater microphone network to track Soviet submarines during the Cold War. To reduce the threat of the general public collecting information about naval operations, data streams are directed to naval facilities in the US where they are screened and then returned to the site for the public to access (Chatterjee and Werman, 2011).
What is this data used for?
Collecting data on the noise in the ocean can provide benchmarks for researchers, as they better understand ambient noise levels, and have a clearer indication of long-term noise levels (Ocean Networks Canada, 2010). Researchers are also using this information to assess the large-scale influence of artificial noise on marine organisms and ecosystems, which would likely make policies or action more targeted and justified.
More recently, researcher Dr. Tzu-Hao Lin, a research fellow from Taiwan, is developing a library of sounds under the Ocean Biodiversity Listening Project, in hopes that anyone can use and access them (Imbler, 2020). He believes that sound may be the best way to monitor the ocean, provide a baseline understanding of healthy remote ecosystems, as well as provide an indicator of booming, or declining populations. Changes in the soundscape could suggest changes in the habitat and its inhabitants (Imbler, 2020).
LIDO provides continuous data which, when stored, could illuminate areas for future research. The database of sound information collected from real-time monitoring would also serve useful in understanding long-term trends in migration patterns, distribution, and relationship with the noise of large cetacean species.
While the realm of the ocean remains something that is still unfamiliar, collecting sound information is a step that grants us more clarity and understanding about what goes on under the sea.
References
André, M., van der Schaar, M., Zaugg, S., Houégnigan, L., Sánchez, A.M. and Castell, J.V. (2011). Listening to the Deep: Live monitoring of ocean noise and cetacean acoustic signals. Marine Pollution Bulletin, [online] 63(1), pp.18–26. Available at: https://www.sciencedirect.com/science/article/pii/S0025326X11002414 [Accessed 10 Feb. 2021].
Chatterjee, R. and Werman, M. (2011). Listening to the Deep Ocean. [online] The World from PRX. Available at: https://theworld.org/stories/2011-12-29/listening-deep-ocean.
Imbler, S. (2020). Could Listening to the Deep Sea Help Save It? The New York Times. [online] 10 Nov. Available at: https://www.nytimes.com/2020/11/10/science/deep-sea-marine-biology-acoustics.html [Accessed 10 Feb. 2022].
Ocean Networks Canada (2010). Listening to the Deep | Ocean Networks Canada. [online] www.oceannetworks.ca. Available at: https://www.oceannetworks.ca/listening-deep [Accessed 10 Feb. 2022].