为了听到彼此的声音，当轮船水下噪音很大时，宽吻海豚会简化并提高它们的声音的声调-克里斯托弗·因塔格利亚塔报道。

Bottlenose dolphins simplify and raise the pitch of their whistles to be heard above underwater shipping¹ noise. Christopher Intagliata reports.

为了听到彼此的声音，当轮船水下噪音很大时，宽吻海豚会简化并提高它们的声音的声调-克里斯托弗·因塔格利亚塔报道。

The oceans are getting louder. And coastal² areas are some of the noisiest, as in this underwater recording³, captured 17 miles off the coast of Ocean City, Maryland.

海洋正变得越来越纷繁嘈杂。沿海地区则是最嘈杂的区域之一，正如这次水下录音的区域，它距离马里兰州大洋城海岸17英里。（马里兰州噪音片段播放）

The noise could be a problem for marine⁴ mammals, 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.

这些船只产生的噪音可能对用声音交流的哺乳动物（类似我们）产生阻碍。“就像我们在一个嘈杂的酒吧，我们必须大声喊叫才能听到对方，它们可能也必须这样做。” Helen Bailey说到，她是马里兰大学环境科学中心的海洋生物学家。

She and her colleagues recorded two months of underwater sounds, in that same area off the coast of Maryland. They used automated⁵ software to fish out 200 bottlenose dolphin whistles from the noise, and visually compared the spectrograms. Here’s a normal whistle.

她和她的同事在马里兰州海岸的同一地区录制了两个月内的水下声音。 他们使用智能自动软件从船只噪音中过滤捕获出200只宽吻海豚声音片段，并比较其视觉频谱图。听这是正常的声音。 <声音片段播放>

But what they found was that dolphins dumbed down the complexity⁶ of their whistles and raised their pitch, when they were competing with shipping noise. Which apparently⁷ helps, but could also hurt, their ability to communicate.

他们发现，当海豚声音想要盖过船只声音时，海豚会降低它们的叫声的复杂性并提高音调。（声音片段2）显然，这么做能起到作用，但也可能伤害它们的沟通能力。

"By using simpler calls, yes, there is a risk 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."

“和安静环境下交流相比，海豚使用简单呼喊而传递信息量确实会减少。这同样适用于年幼的海豚，它们实际上通过听其它海豚的叫声来学习这些声音。所以它们听到的声音更简单。”

The results—and a few of those spectrograms—are in the journal Biology Letters. [Leila Fouda et al., Dolphins simplify their vocal⁸ calls in response to increased ambient noise]

该项研究结果以及其中一些光谱图，发表在“生物学快报”上。 [Leila Fouda等人著，《海豚在环境噪音的增加的情况下会简化它的叫声》Dolphins simplify their vocal calls in response to increased ambient noise]

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 chronic⁹ roar of ships and boats that Bailey wants people to ponder. "I think people think about boats in terms of the emissions¹¹, just like with cars. And I think what we need to think about is sound is also an emission¹⁰."

调查地点在未来将会建造风力发电厂，这意味着在建造时将会产生很多巨大噪音。在那之前，我想人们应该去思考下这片区域来往船只长期造成的噪音。“我认为人们应该像看待汽车尾气排放一样看待船只噪音，认识到噪音也是一种排放。”