This threat is much more “out of sight, out of mind”. As humans do NOT spend much – or possibly any – time under the water (other than scuba divers), we don’t understand the full effect of underwater noise on ocean wildlife. Sound in air, such as students yelling across the playground, can only be heard within a relatively short distance. Sound in the water, however, can travel much further. Sounds that have a high frequency (ie from dolphins, some orca calls, jet skis, speed boats, etc) can travel up to 2 kilometers. Sounds that are of a low frequency (i.e.from blue whales, certain types of sonar, large tanker vessels) have sounds that can travel 100’s, if not 1000’s of kilometers.
Being able to hear messages and respond correctly is critical for marine mammals. Noise pollution and bio-acoustics are becoming more researched and is an interesting field of study. There are many ways to reduce sound in the ocean, some as simple as slowing some marine vessels down, changing props and other design modifications, and using sound barriers during construction.
Questions to think about:
- What is marine noise pollution?
- How does marine noise pollution affect marine life?
- Do marine animals, particularly mammals (whales, seals, sea lions, etc.) make sound?
- What is the concern with the ocean getting noisier?
- What do different sources of noise sound like underwater?
- How do scientists study sound in the ocean?