VOA慢速英语2021--人类让海洋变得太吵了

Humans Are Making Oceans Too Noisy

Human activity is changing the surface and temperature of the planet. But new research shows it is also changing the sound of the Earth's oceans and seas.

Scientists say the changes in the sounds of our oceans, seas, and other waterways affect many marine¹ animals -- from very small shrimp² to huge whales.

Sound travels "very far underwater," Francis Juanes told the Associated Press. Juanes is an ecologist at the University of Victoria in Canada. He is also co-writer of the recent research published in the magazine, Science.

"For fish," he explained, "sound is probably a better way to sense their environment than light."

Sounds help fish and other marine animals survive. They use sounds to communicate with each other. Sounds also help some ocean animals find food and avoid their hunters. Many ocean animals use sounds to find good places to mate.

However, increased noise from humans is making it harder for these animals to hear each other. The noise is coming from shipping³ traffic, motorized fishing ships, underwater oil and gas exploration, offshore⁴ construction, and other noisy human activity.

"For many marine species, their attempts to communicate are being masked by sounds that humans have introduced," said Carlos Duarte. The marine ecologist at the Red Sea Research Center in Saudi Arabia co-wrote the paper with Juanes.

Experts at the U.S. National Oceanic and Atmospheric⁵ Administration, or NOAA, explain the term masking on its website. Masking happens when one or more noises in the water block sound important to a marine animal's existence.

The Red Sea, Duarte said, is one of the world's most important shipping passages. It is full of large ships traveling to Asia, Europe, and Africa. Some fish and other animals, he said, now avoid the noisiest areas.

Also, the overall number of marine animals has gone down by about half since 1970. In some parts of the ocean, scientists now record "fewer animals singing and calling than in the past – those voices are gone," said Duarte.

Juanes and Duarte examined studies and research articles documenting changes in noise volume and frequency in the world's oceans. Then they put together a detailed⁶ picture of how the ocean soundscape is changing and how marine life is affected⁷.

Scientists use underwater devices to record fish sounds. These sounds are in the same low frequencies as shipping traffic noise. NOAA experts state that masking is most noticeable when "a noise is at the same frequency and loudness as biologically important sounds, such as mating calls."

Climate change, the researchers found, also affect physical processes that shape ocean sounds. These include such things as wind, waves, and melting ice

Experts at NOAA say that effects of noise on marine mammals are not well understood. However, some studies suggest that noise may cause hearing loss. The stress from human noise might also affect the immune system - an animal's natural defense⁸ system - as well as reproductive health or behavior.

"Imagine having to raise your kids in a place that's noisy all the time," said Joe Roman. He is a marine ecologist at the University of Vermont and was not involved in the research. Roman added that it should come as no surprise that many marine animals are showing higher "levels of stress due to noise."

Another marine ecologist not involved with the paper is Neil Hammerschlag of the University of Miami.

"When people think of threats facing the ocean," he said, "we often think of climate change, plastics, and overfishing. But noise pollution is another essential thing we need to be monitoring."

"If you make something for the ocean," Hammerschlag suggested, "think about how to make it quieter."

Scientist Juanes says sound pollution may be easier to deal with than other ocean threats. "In theory," he said, "you can reduce or turn off sound immediately. It's not like plastics or climate change, which are much harder to undo⁹."

Words in This Story

marine – adj. of or relating to the sea or the plants and animals that live in the sea

introduce – v. to put in

communicate – v. to give information about (something) to someone by speaking, writing, moving your hands, etc.

species – n. biology : a group of animals or plants that are similar and can produce young animals or plants : a group of related animals or plants that is smaller than a genus

volume – n. the degree of loudness or the intensity¹⁰ of a sound

frequency – n. the number of waves of sound or energy that pass by a point every second

stress – n. a state of mental tension and worry caused by problems in your life, work, etc.

essential – adj. extremely important or necessary

monitor – v. to watch, keep track of, or check usually for a special purpose

1 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

2 shrimp   

n.虾，小虾；矮小的人

参考例句：

• When the shrimp farm is built it will block the stream.一旦养虾场建起来，将会截断这条河流。
• When it comes to seafood,I like shrimp the best.说到海鲜，我最喜欢虾。

3 shipping   

n.船运（发货，运输，乘船）

参考例句：

• We struck a bargain with an American shipping firm.我们和一家美国船运公司谈成了一笔生意。
• There's a shipping charge of ￡5 added to the price.价格之外另加五英镑运输费。

4 offshore   

adj.海面的，吹向海面的；adv.向海面

参考例句：

• A big program of oil exploration has begun offshore.一个大规模的石油勘探计划正在近海展开。
• A gentle current carried them slowly offshore.和缓的潮流慢慢地把他们带离了海岸。

5 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

6 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

7 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

8 defense   

n.防御，保卫；[pl.]防务工事；辩护，答辩

参考例句：

• The accused has the right to defense.被告人有权获得辩护。
• The war has impacted the area with military and defense workers.战争使那个地区挤满了军队和防御工程人员。

9 undo   

vt.解开，松开；取消，撤销

参考例句：

• His pride will undo him some day.他的傲慢总有一天会毁了他。
• I managed secretly to undo a corner of the parcel.我悄悄地设法解开了包裹的一角。

10 intensity   

n.强烈，剧烈；强度；烈度

参考例句：

• I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
• The strike is growing in intensity.罢工日益加剧。