ls99
Give me a museum and I'll fill it. (Picasso) Give me a forum ...
- Joined
- May 2, 2008
- Messages
- 6,511
As Nords pointed out, many critters make all sorts of sounds in the ocean, some audible to humans others beyond our range of hearing.
My experience from long ago when aboard an Oceanographic resaerch ship, is cacaphony of sounds all over the spectrum. Some are known which species the noise originates from some not. We used to drag along hydrophone (underwater microphone) strings which were nearly a mile long for specific sonar listening purpose. They were very wide band, could identify a few hertz, to well beyond 50 Khz. The recorders were tuned and and filtered for specific frequencies.
At times we deployed sonobuoys, which are floating radio transmitters, with hydrophones dangling deep down. The range of sounds were somewhat different from the towed array. Especially if dangling below the thermocline.
We had the capability to route the hydrophone output to an amp and loudspeaker. At times we would turn it on just for amusement. Therange of sounds varied from regions ie. North Atlantic, Pacific, Indian Ocean or off Antarctica. The variety also changed by the time of day, so much that without looking out one could tell roughly morning, mid day, evening, late evening or midnight.
Our precision depth recorde also would show trends of mini critters migrating to near the surface in the evening and disappear in the morning.
Anotherwords what they thought they heard could have been anything. Many of the critters communicate by very short squeaks, whales tend to have long moans among other sounds. They can be heard for hundreds of miles.
As the old Ginzu knife commercals used to say, and there is more, a lot more.
My experience from long ago when aboard an Oceanographic resaerch ship, is cacaphony of sounds all over the spectrum. Some are known which species the noise originates from some not. We used to drag along hydrophone (underwater microphone) strings which were nearly a mile long for specific sonar listening purpose. They were very wide band, could identify a few hertz, to well beyond 50 Khz. The recorders were tuned and and filtered for specific frequencies.
At times we deployed sonobuoys, which are floating radio transmitters, with hydrophones dangling deep down. The range of sounds were somewhat different from the towed array. Especially if dangling below the thermocline.
We had the capability to route the hydrophone output to an amp and loudspeaker. At times we would turn it on just for amusement. Therange of sounds varied from regions ie. North Atlantic, Pacific, Indian Ocean or off Antarctica. The variety also changed by the time of day, so much that without looking out one could tell roughly morning, mid day, evening, late evening or midnight.
Our precision depth recorde also would show trends of mini critters migrating to near the surface in the evening and disappear in the morning.
Anotherwords what they thought they heard could have been anything. Many of the critters communicate by very short squeaks, whales tend to have long moans among other sounds. They can be heard for hundreds of miles.
As the old Ginzu knife commercals used to say, and there is more, a lot more.
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