Science Update - Aquatic Noise Pollution

Bob - This week on Science Update, noise pollution is now a problem in seas as well as cities. But first, Chelsea has a much more pleasant noise to play for us-and you'll probably be surprised by its origin.

Chelsea - If a volcano could play piano, this is what it would sound like. Physicist Domenico Vicinanza of CERN in Switzerland created the music by converting a seismogram from Mount Etna into a score.

Domenico - If the volcano is quiet, the melody of the piano is confined in the middle part of the piano. As soon as the volcano is becoming louder and louder, the melody on the piano starts to scatter up and down, reaching higher and lower notes.

Chelsea - So how will this help? Vicinanza says people are often better at picking out patterns by ear than by eye, so this technique could help scientists find patterns in seismic activity across many volcanoes.

Domenico - Our aim is to use all the recorded data, to transform them into music, and try to understand what happens when the volcano starts to become louder and erupts, and so we can say which is the signature tune, the signature melody which can be taken as a signal of an imminent eruption or imminent earthquake.

Chelsea - He adds that this technique could prove useful in analyzing data in other fields, from stock-market numbers to patterns in language. He also hopes it will be welcomed by musicians as a new way to create nature-inspired tunes.

Bob - Thanks, Chelsea. Well, here's another tune of sorts, but one that's not so welcome.

Bob - It's the sound of a ship-underwater. Scientists think it might interfere with how whales and other sea mammals communicate and find food. Now a team has discovered that ambient underwater noise has increased ten times since the 1960s-at least in the Pacific. But it's not just that the number of ships has gone up. John Hildebrand of Scripps Oceanography says traffic has only doubled since that time.

John - So a very significant part of the increase comes from the fact that the ships themselves must be generating more noise-the ships are bigger, they travel faster, they have greater total tonnage that they're carrying.

Bob - Hildebrand and his colleagues were able to do this analysis because they found declassified Navy reports from the 60s on the ambient noise in the Pacific-part of the Navy's Cold War defense. They were then able to make recordings in the same spot and compare them. Although it's not hard to prove that noise has gone up, he says what is hard to prove is that it's having an effect on the mammals.

John - The insidious thing about this is that the ambient noise has been increasing at probably a fairly steady pace, so there wouldn't be some dramatic event where all of a sudden the marine mammals would be doing something differently. So it's tricky to figure out where the impact has been.

Bob - But he says it may not be as hard as it might seem to convince the shipping industry that noise is a problem-quieter ships would be better for the crew and should be more energy-efficient. He adds that in looking for a solution, scientists may turn again to the Navy, who are, after all, experts in being quiet underwater.

Chelsea - Thanks, Bob. That's all for this week. Next week we'll talk about some ants that do some amazing acrobatics. Until then, I'm Chelsea Wald.

Bob - And I'm Bob Hirshon, for AAAS, The Science Society. Back to you, Naked Scientists.