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Humpback whales are one of most common whales heard on the MARS hydrophone. The inset shows a spectrogram of humpback whale songs from Monterey Bay. Whale image courtesy of NOAA. For centuries poets and writers have imagined the depths of the ocean as eerily quiet. But scientists now know that the oceans, and especially coastal areas, are full of sound from both natural and human activities.
Starting this week, anyone can eavesdrop on sounds in the deep sea via a continuous audio stream that carries live sound from meters 3, feet below the surface of Monterey Bay.
Basemap: Google Maps. The sounds on this stream come from an underwater microphone hydrophone that the Monterey Bay Aquarium Research Institute placed on the seafloor in The hydrophone is located about 30 kilometers 18 miles from shore, just west of Monterey Bay. It is attached to the MARS undersea cabled observatory , which carries data from the hydrophone back to shore. For over two years MBARI researchers have been fascinated by the variety of sounds captured by this hydrophone.
Although the MARS hydrophone is located on the deep seafloor, most of the sounds it picks up are from animals and activities higher up in the water or even at the sea surface. For example, it is common for the hydrophone to pick up the calls of sea lions, dolphins, and other near-surface animals, as well as the sounds of rain, waves, and wind blowing over the sea surface. High-pitched sounds, such as dolphin clicks, do not travel very far through the water, so if these sounds show up in the stream they are probably being generated within a few kilometers of the hydrophone.
However, the low-pitched sounds of ship engines can travel dozens of kilometers, and some whale calls may come from animals hundreds of kilometers from Monterey Bay. The MARS hydrophone can capture sounds both above and below the range of human hearing. The new live stream does not carry high-pitched sounds above human hearing, but it does include very low sounds such as those produced by some whales.
Listeners can hear these sounds if they have good headphones or subwoofer speakers. Ryan notes that sounds in the bay can vary dramatically.
There is a minute delay for computer processing and archiving between the time when the sounds are captured by the hydrophone and the time that they show up on the audio stream. It is connected to the MARS cabled ocean observatory, which supplies power and a high-speed data connection to shore. Recordings on this web page help visitors identify and learn about the calls made by different types of whales and dolphins, as well as natural processes such as rain and earthquakes.
This will allow thousands of visitors to hear the sounds of Monterey Bay. For researchers and others who would like to explore sounds previously detected by the hydrophone, the MBARI team created a web page where visitors can browse through two and one half years of spectrograms. Although visitors cannot hear the sounds using the spectrogram browser, they can look for certain types of sounds or find out what the hydrophone recorded during certain days or months.
Their work is revealing new information about the behavior of whales and other marine mammals along the Central California coast. Beyond their scientific value, the recordings from the MARS hydrophone are fascinating in their own right. So even if poets and writers have to give up the idea of a silent sea, the sounds revealed the MARS hydrophone provide a wonderful and insightful alternative. For additional information or images relating to this article, please contact: Kim Fulton-Bennett , kfb mbari.
Research programs at the Monterey Bay Aquarium Research Institute MBARI encompass the entire ocean, from the surface waters to the deep seafloor, and from the coastal zone to the open sea.
The need to understand the ocean in all its complexity and variability drives MBARI's research and development efforts. April 24, Eavesdropping on the deep— New live streaming audio from a deep-sea hydrophone. Listen to live audio Your browser does not support the audio player to play the live stream from Monterey Bay. Related news stories. September 16, — A new study shows how the amount of humpback song in Monterey Bay varies over days, months, and even years.
June 24, — Gray whales are dying in large numbers along their Pacific Coast migration route. Scientists are looking for clues to explain this phenomenon. July 9, October 22, June 22, Science Upper-ocean systems Midwater research Seafloor processes Areas of study Biology Chemistry Geology Ocean acidification Physical oceanography and climate change Past research Research publications.
Technology Solving challenges Taking the laboratory into the ocean Enabling targeted sampling Advancing a persistent presence Emerging and current tools Technology publications Technology transfer. Products What is happening in Monterey Bay today? Financial reports Guest information Library Making an impact.
Sonar so und na vigation r anging is a technique that uses sound propagation usually underwater, as in submarine navigation to navigate , communicate with or detect objects on or under the surface of the water, such as other vessels. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation,  and SODAR an upward-looking in-air sonar is used for atmospheric investigations. The term sonar is also used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from very low infrasonic to extremely high ultrasonic.
Underwater acoustics - Hydrophones - Calibration in the frequency range 0,01 Hz to 1 MHz