《经济学人》双语：如何减少船舶噪音对海洋生物的伤害？

原文标题：
Still waters
Noise-dampening tech could make ships less disruptive to marine life
Solutions include bendy propellers and “acoustic black holes”
静水
降噪技术可减少船舶对海洋生物的干扰
解决方案包括弯曲螺旋桨和 “声学黑洞”

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MORE THAN 1,000 metres below the surface of the oceans, darkness reigns.
在海平面以下1000多米深的地方，黑暗笼罩着一切。

For animals living in this perpetual twilight, vision is irrelevant; acoustic signals, instead, are how they navigate, communicate and search for food.
对于生活在这片长久昏暗环境中的动物来说，视觉已不再重要；相反，声音信号才是它们导航、交流和觅食的方式。

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That way of life has come under threat from decades of increasing human noise.
几十年来，人类的噪音越来越大，这对海洋动物的生活方式构成了威胁。

A leading culprit is shipping, contributing to a rise in underwater volume of approximately 3.3 decibels per decade.
首要原因是海运，它导致水下噪音量每十年大约增加3.3分贝。

The trend shows little sign of levelling off. By one estimate, shipping-noise emissions double every 11.5 years.
这一趋势尚无减缓的迹象。据估计，海运噪音量每11.5年翻一番。

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With roughly 90% of traded goods travelling by sea, quieting the ocean through reductions in shipping itself is untenable.
由于约90%的贸易货物通过海运，仅通过减少海运来让海洋恢复宁静是行不通的。

Efforts to make ships more efficient, and therefore less polluting, are also likely to reduce noise. But experts say those measures will not do enough to restore quiet.
尽管提高船运效率来减少污染的努力也可能会降低噪音，但专家认为，这些措施还不足以让海洋恢复宁静。

That is why a range of technologies are being developed—from modified propeller designs to noise-dampening metamaterials—that could allow humans and other animals to co-exist in the ocean.
正因如此，人们正在研发一系列技术——例如改进螺旋桨设计、使用降噪超材料——以便人类和其他动物能在海洋中和谐共存。

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Much of the underwater noise a ship produces comes from its propeller.
船舶产生的水下噪音大部分来自螺旋桨。

As the blades spin, areas of low pressure are formed in their wake which cause the water to boil and produce bubbles, a process known as cavitation.
当螺旋桨叶片旋转时，会在其尾部形成低压区，导致水沸腾并产生气泡，这一过程被称为空化现象。

When those vapour cavities collapse, a low-frequency noise is produced.
当这些气泡空腔破裂时，就会产生低频噪音。

Such noise can travel thousands of metres underwater without losing strength, disrupting the movements of blue and humpback whales which use these frequencies to communicate.
这种噪音能够在水下传播数千米而不衰减，从而干扰蓝鲸和座头鲸等利用这些频率进行交流的海洋生物的活动。

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One solution, being developed by researchers at the University of British Columbia (UBC), incorporates flexible polymers into the metal propeller blades, allowing their tips—one of the main sites of cavitation—to bend and twist.
不列颠哥伦比亚大学 (UBC) 的研究人员正在探索一种解决方案，将柔性聚合物融入金属螺旋桨叶片中，使叶片尖部（空化现象的主要发生部位之一）能够弯曲和扭转。

This movement prevents bubbles from forming and thereby reduces the noise the blades produce, says Rajeev Jaiman of UBC.
不列颠哥伦比亚大学的拉吉夫·贾曼表示，这种弯曲和扭转的动作能够防止气泡的形成，从而降低叶片所产生的噪音。

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Based on simulations, the design could reduce cavitation noise by 20 decibels.
根据模拟结果，这种设计可以将空化噪音降低20分贝。

Dr Jaiman says researchers are working closely with marine biologists to understand how deep-sea life would perceive the difference.
贾曼博士说，研究人员正在与海洋生物学家密切合作，以探究深海生物如何感知这种差异。

The researchers intend to start testing a prototype in tugboats next year.
研究人员打算明年开始在拖船上测试这种设计的原型。

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Cavitation can also be mitigated by increasing the number of bubbles, rather than reducing them.
增加气泡数量，而不是减少气泡，同样可以缓解空化现象。

Researchers at MARIN, a Dutch research institute, have blown bubbles onto a propeller’s blades, filling the vapour cavities left behind, cushioning their collapse and dampening the resulting noise.
荷兰研究机构MARIN的研究人员在螺旋桨叶片上吹制气泡，填满留下的气穴，缓冲气泡空腔破裂并降低由此产生的噪音。

Model-scale tests of this system in a wave basin showed a 12-decibel decrease in low-frequency noise at average container-ship speed.
他们在波浪水槽中对这一系统进行了比例模型试验，结果显示，在集装箱船的平均航速下，低频噪音降低了12分贝。

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But shipping noise does not come only from the propeller.
但船舶噪音并非仅源自螺旋桨。

Roughly 20% comes from the vessel itself, as engines and generators chug and the ship’s components vibrate. At low speeds, this percentage rises.
大约20%的噪音来自船舶本身，因为发动机和发电机会发出轰鸣声，船舶部件也会振动。在低速航行时，这一比例还会上升。

To mitigate this, MARIN researchers have experimented with a bubble screen generated from ducts positioned in belts around the outside of the hull.
为了缓解这一问题，MARIN的研究人员试验了一种气泡屏，即一种由安装在船体外围管道产生的气泡屏。

These deploy a skirt of air bubbles around the rear of the ship, where most machinery sits, preventing noise from spreading.
这些气泡在船体后部（即大部分机械设备所在的位置）周围形成一道气泡裙，可以防止噪音扩散。

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Such bubble screens have been used before, says Johan Bosschers of MARIN, but only for secret military ships—which meant there were few data available about how well they worked.
MARIN的约翰·博斯彻斯说，这种气泡屏以前也曾使用过，但只用于秘密军舰——这意味着关于其性能的数据很少。

Now that others want quiet travel too, researchers need to validate their effectiveness.
现在其他人也希望实现降噪航行，研究人员需要验证其有效性。

Model tests have shown that frequencies around 1 kilohertz (the preferred bandwidth of seals and toothed whales) can be reduced by up to 22 decibels, at slow speeds.
比例模型试验表明，在低速航行时，频率在1千赫兹附近（这是海豹和齿鲸偏好的频率范围）的噪音可以降低多达22分贝。

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More avant-garde ideas are also on the table.
还有一些更前卫的想法也被提了出来。

Giovanni Rognoni, a marine-engineering researcher at the University of Trieste, is investigating whether a so-called acoustic black hole can help.
意大利的里雅斯特大学的海洋工程研究员乔瓦尼·罗格诺尼正在探索所谓的“声学黑洞”是否有助于降噪。

[Paragraph 11]
Such an object, which aims to trap sound the way cosmological black holes trap light, can be built by welding steel beams that taper to a thin point to the inside of the ship’s hull.
这种装置的目的是像宇宙学黑洞捕捉光线那样捕捉声音，可以通过将逐渐变细的钢梁焊接到船体内壁来建造。

Laboratory tests show this can reduce vibrations by as much as the best currently available alternatives, without any of the added weight, fire risk or toxic fumes these often involve.
实验室测试表明，这种方法与目前最好的替代方法一样，可以减少振动，而且不会增加重量、火灾风险或有毒烟雾。

[Paragraph 12]
Tom Smith, a researcher in naval architecture at University College London, says that technological solutions for reducing ocean noise abound.
伦敦大学学院船舶工程专业的研究员汤姆·史密斯表示，目前不缺海洋降噪的技术方案。

What is missing, however, is funding to test them at sea, and a willingness on the part of shipbuilders and owners to commit to using them.
然而，目前的问题是缺乏海上测试的资金，以及造船商和船东使用这些技术的意愿。

Refitting ships to be quieter is complex and costly, and not seen as a priority at present.
要使船舶变得更加安静，需要进行复杂的改装，且成本高昂，目前还不是当务之急。

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That may change. Some seaports, such as the Vancouver Fraser Port Authority, now offer discounts equivalent to thousands of dollars for ships that meet the highest level of noise reduction.
这种情况可能会有所改变。一些海港，如温哥华弗雷泽港务局，目前正为达到最高降噪标准的船舶提供高达数千美元的折扣。

And, says Dr Bosschers, quieter ships may also turn out to be more efficient.
而且，博斯彻斯博士指出，噪音更低的船舶或许也会更节能。

Now that the International Maritime Organisation has pledged to reduce carbon emissions from international shipping by 70%, relative to 2008 levels, by 2040, this may prove too good a deal to resist.
既然国际海事组织已经承诺到2040年将国际海运的碳排放量较2008年水平降低70%，那么这可能是一个无法抗拒的绝佳机会。

（恭喜读完，本篇英语词汇848左右，有删减）
原文出自：2024年10月12日《TE》Science & technology版块

精读笔记来源于：自由英语之路
本文翻译整理: Irene
本文编辑校对: Irene
仅供个人英语学习交流使用。

【重点句子】（3个）
For animals living in this perpetual twilight, vision is irrelevant; acoustic signals, instead, are how they navigate, communicate and search for food.
对于生活在这片长久昏暗环境中的动物来说，视觉已不再重要；相反，声音信号才是它们导航、交流和觅食的方式。

That is why a range of technologies are being developed—from modified propeller designs to noise-dampening metamaterials—that could allow humans and other animals to co-exist in the ocean.
正因如此，人们正在研发一系列技术——例如改进螺旋桨设计、使用降噪超材料——以便人类和其他动物能在海洋中和谐共存。

What is missing, however, is funding to test them at sea, and a willingness on the part of shipbuilders and owners to commit to using them.
然而，目前的问题是缺乏海上测试的资金，以及造船商和船东使用这些技术的意愿。