My sweet physheads have completed lab activities for the fall Physics 53 course and are now finishing the last of the material for recitation and preparing for the final exam — my how time flies. For the lab on mechanical waves and sound in particular, many students choose to submit a short research blurb about acoustics in a marine environment and so I share this Wired Science blog link about the changing nature of blue whale songs. Check the link above for the full blog…here is a teaser:
All around the world, blue whales aren’t singing like they used to, and scientists have no idea why.
The largest animals on Earth are singing in ever-deeper voices every year. Among the suggested explanations are ocean noise pollution, changing population dynamics and new mating strategies. But none of them is entirely convincing.
“We don’t have the answer. We just have a lot of recordings,” said Mark McDonald, president of Whale Acoustics, a company that specializes in the sonic monitoring of cetaceans.
McDonald and his collaborators first noticed the change eight years ago, when they kept needing to recalibrate the automated song detectors used to track blue whales off the California coast. The detectors are triggered by songs that match a particular waveform, and every year, McDonald had to set them lower.