Kelly Cameron from section 2 asked: When did we first realize that we generated noise pollution in the ocean through shipping noise, sonar, and air gun arrays, which was causing blue whales to die? What was the initial reaction?
- We have been generating noise pollution since the industrial revolution. However the noise was never really bad. It has only been within the past 20 years that people have really taken action against boat traffic, sonar, and air gun arrays. It really is a combination of all three that cause blue whales to die. A ships propeller runs on the same frequency as blue whale communication causing accidental collisions between boat traffic and blue whales leaving scars or even killing them when they collide. Sonar is a high frequency sound, which is very close and similar to killer whale communication. This drives blue whales away from the area and blocks communication because they think a predator is in the area and drives them away from there food or onto a beach. An air gun array just messes everything up. If you were in the water when one went off your eardrums would explode instantly. This messes with communication and disorients the whale causing it to beach itself. The initial reaction was very low. Nobody fully understood the importance and the balance that the oceans play in our lives. many people saw a beached whale and said aww poor thing but never really understood that they had a hand in causing it. Today however is a different story because we understand just how much the oceans mean to us.
 |
| Prop marks on the back of a humpback whale |
Jessica D. from section 52 asked: Brent, I don't know a whole lot about sound. I was wondering, if I was under water and a gun array went off a few miles away or some submarine somewhere used their sonar, what would I hear? How is my hearing different from dolphins and whales?
- To start water amplifies and carries sound for a very long distance. So if you were a few miles away from an air gun array you would hear it because the frequency of the noise is within human auditory range. Now if a submarine started its sonar a couple miles away you wouldn't hear it because the frequency is out of our auditory range but it is still there. What I mean by frequency is wave length. the shorter the wave length the more intense the sound, and the longer the wave length the lower the sound. Now the human auditory range can hear a certain range a frequencies from 20 Hertz to 20 Kilohertz, and a Whales auditory range can stretch anywhere from 10 Hertz to 31 Kilohertz giving them a much wider auditory range. Which is why Whales often collide with ships and beach themselves because of sonars to escape what they think is a predator because sonars very closely resemble the frequency of a killer whale which is know to feed on other whales.
 |
| Some noises in the ocean natural and non natural |
Elizabeth S. sec. 51 I was wondering about your hydrophone. Maybe you said this already but are you able to record the sound or do you just listen to it and evaluate it somehow? If you can record it, are you also able to upload it so we can hear what it sounds like? And once you record it, how do you evaluate or measure the sound? How do you use it in your research?
ReplyDelete