December 14, 2012

Mapping Sound Waves in a Noisy Ocean

by Christine Hoekenga

For most humans, sight is our dominant sense.  We use our eyes to monitor our surroundings,  get around, observe and connect with other people, find and prepare food, learn about the world, and much more.  Common phrases like “seeing is believing” and “a picture is worth a thousand words” are testament to our reliance on sight.  But some animals, such as whales and dolphins (called cetaceans by biologists), rely much more heavily on sound and the sense of hearing.

Map of Shipping Noise in Atlantic Ocean

This map shows the noise created by shipping traffic alone in the Atlantic Ocean. The colors represent the range of noise levels. Dark blue areas are in the 50 decibel range–similar to a quite radio, a regular spoken voice or a gentle breeze. Red areas are in the 115 decibel range–similar to a nearby thunder clap or a rock concert. Researchers at NOAA and other organizations are concerned about the effects of increasing underwater noise on marine life.  Sources: NOAA Underwater Sound Field Mapping Working Group; HLS Research; NCEAS

 

Sound is a wave (a traveling disturbance) that moves through a medium like air or water.  Underwater, sound travels much faster and farther than light, allowing animals to communicate over long distances and to sense and navigate their surroundings even in dark or murky water where sight is not very helpful.  Too much noise or sudden, unexpected sound waves can startle and confuse marine animals–in some cases causing injuries or endangering their lives. That’s why scientists at the National Oceanic and Atmospheric Administration (NOAA) have been working to map human-made sounds in the sea, such as shipping traffic, oil and gas exploration, and military sonar.

Our image of the week is a visualization of just one type of underwater sound that scientists have mapped: the noise caused by shipping traffic in the Atlantic Ocean.  As shipping and other human activities have increased over the last several decades, the ocean has become a noisy place, and researchers are working to better understand the effects of that noise on marine life.

LEARN MORE
For more about the science of waves and how they travel, visit our module Waves and Wave Motion: Describing Waves.

To understand the underlying math of wave motion, check out our module Wave Mathematics: Trigonometric Functions.

For more in-depth information on how noise in the ocean effects marine life, browse the Discovery of Sound in the Sea website.  You can also listen to audio clips of natural and human-made sounds from whale songs to torpedoes.

For more about the project to map sound in the ocean, read the New York Times article “A rising tide of noise is now easy to see,”  or visit the NOAA Cetacean and Sound Mapping website.

Christine Hoekenga

Written by

Christine is a freelance writer, editor, and content strategist, specializing in science and nature. She holds an Bachelor's degree in Environmental Science and Media Studies and a Master's of Science Writing. She has been working in science communication and education for nearly a decade as a journalist, an organizer for conservation groups, and a museum educator. Before joining the Visionlearning team, she served as the New Media and Online Community Manager for the Webby award-winning Smithsonian Ocean Portal. Christine is assisting Visionlearning with developing new modules and glossary terms, managing the blog, and outreach through social media.

The views expressed above do not necessarily represent those of Visionlearning or our funding agencies.