This is scientific American 60 second science. I'm Christopher Intagiyata.

The oceans are getting louder and coastal areas are some of the noisiest, as in this

underwater recording captured 17 miles off the coast of Ocean City, Maryland.

The noise could be a problem for marine males, which like us use sound to communicate.

Just like if we're in a noisy bar, we have to shout to each other.

They might have to do that too.

Helen Bailey is a marine biologist at the University of Maryland Center for Environmental Science.

She and her colleagues recorded two months of underwater sounds in that same area off the coast of Maryland.

They used automated software to fish out 200 bottlenose dolphin

whistles from the noise and visually compared the spectrograms. Now here's

what a normal whistle sounds like. But what they found was that dolphins dumb down the complexity of their

whistles and raise their pitch when they were competing with shipping noise

like this, which apparently helps, but could

also hurt their ability to communicate.

By using simpler calls, yes, there is a risk that they're not communicating as much

information as they would if it was quieter. Also for younger dolphins, they actually

learn these sounds from hearing other dolphins so they're hearing this much simpler

language. The results and a few of those spectrograms are in the journal

Biology Letters. The survey site is the proposed future home of a wind farm which could mean lots of noise as the huge towers are installed.

Until then it's the chronic roar of ships and boats that Bailey wants people to ponder.

I think people think about boats in terms of sort of the emissions, just like with cars.

And I think what we need to think about is that sound is also an omission.

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