There are few sounds in the natural world that are as soothing as the restless sea – so it’s a shame we’re drowning it out.

In yet another assault on the biophony, human beings are flooding the depths of the oceans with noise pollution, turning the formerly Silent World into a busy-sounding place. All humanity’s sea-going machinery send out vibrations – some of them very substantial indeed – and for marine creatures that have evolved to pick up the faintest of noises and communicate with natural sonar, this is indeed a problem. Shockingly, a report by the International Fund for Animal Welfare (Ifaw) argues that the range of blue whale communication has reduced down to just a tenth of what it was before humans starting plying the waves with powered-propeller vessels.

When it comes to airborne noise pollution, there are at least regulations – because this noise directly affects people. There are currently no such restrictions on noise pollution at sea. It’s true that we’re talking about the uppermost layers of a truly vast volume of seawater – the oceans cover 71% of our planet, around 1.3 billion cubic kilometres – but those upper layers are where most marine life thrives. It’s an even more urgent issue to consider when worldwide deep-sea drilling is set to intensify as our fossil fuels start running out, forcing us further and further away from the shoreline.

First the air, then the ground, then space, and now the oceans. We’ve been highly inventive in our methods of polluting every corner of the natural environment, so let’s hope we can be just as creative in cleaning them up – before our neglect reaches new depths.

Further reading:  Ifaw: “Ocean Noise: Turn It Down” (PDF).

Image: Kalandrakas

Birds twitter. Cats meow. Dogs bark. And elephants…rumble.

It’s one of the most curious corners of the biophony – the low-frequency noise (on the lower edge of our own hearing) that elephants send into the ground to attract a mate. The vibration is picked up by potential partners through their forelegs, and from there it’s transmitted to a bone in their middle ear (here’s the science of it – pdf). Amazingly, this may work over distances of up to 6 miles. It’s only one aspect of the diverse, sophisticated language that elephants employ, but it’s one that environmentalists are using to save elephant lives.

In Namibia, elephants are only protected within the boundaries of the Etosha National Parks. When bull elephants stray outside, they trample on crops, destroy property and threaten livelihoods – and enraged farmers respond with hails of bullets. If the elephants can be encouraged to respect borders, they will remain safe.

And that’s where rumblings come in. By sending similar vibrations into the ground using speakers, park rangers could lure elephants deeper into the park where they’re safest. (Since the rangers will be attracting bull elephants on heat, it’s safe to assume Jeep maintenance will become an even higher priority).

So are elephants unique in using this seismic chatline? And with all the noise we make from mining and construction, how many of the natural world’s conversations are we butting in on?

Image: lillarkie