Noise in the Sea
Sound is one of the most important means of communication for creatures underwater. In the clear water of a coral reef you can see up to 200 feet at most. In muddier waters, visibility can shrink to three feet. But sound travels far and fast in the sea. Thus many marine animals are dependent on hearing for various purposes. Some whales and dolphins use echolocation(locating objects by reflected sound) for navigation. Male toadfish attract females by buzzing. But background noise from sources such as boat engines can mask familiar sounds and make life more dangerous. When captive toadfish were played ferryboat sounds in a 2005 experiment, they had trouble hearing one another. Since the nineteenth century, boat noise has grown relentlessly, following global economic growth. Of goods traded internationally, 80 percent are shipped by sea. As trade volumes increase, so does noise.
The much greater density of seawater carries sounds farther and faster than air. Noise travels about five times more quickly in the sea, reaching 5,000 feet per second in temperate waters. It drops off less quickly in water than in air, so noises can be heard at far greater distances. Higher pitched noises have higher frequency, and lower pitched noises have lower frequency. High frequencies weaken more quickly than low frequencies, so deep notes go farther, as shown by the fact that some of the great whales communicate over hundreds or even thousands of miles using low frequency rumbles(thunder-like sounds). Sounds go farthest of all if animals take advantage of a strange attribute of the sea. Between the warm lighter layer at the surface and the cool dense water below there is a narrow region where sounds travel in a similar way to light in a fiber-optic cable. Differences in density across this boundary-the thermocline-keep sound waves produced there in a narrow channel, where they lose little energy as they travel. Before the days of satellite beacons the United States Navy issued pilots with an explosive charge. If they had to make an emergency landing in the sea, they were to lower the charge on a string and explode it in this sound-carrying channel. The sound would carry to sensors perhaps thousands of miles away, where the location of the pilot could be determined.
Because most animals can only hear over a limited frequency range, the effect of noise on animals also depends on its frequency. The continuous low-frequency sounds produced by human activities in the sea overlap pretty closely with the hearing ranges of fish and whales. There are signs that some try to compensate. Northern right whales call louder when there is background boat noise. The more noise there is, the louder they call. They also call about eight tones higher than they did in the 1950s, probably in an effort to be heard above the low-frequency drone of engines. But there is a limit to how loud they can call. As noise levels continue to rise, whales will become increasingly isolated. Since there are fewer than 400 northern right whales left, isolation could seriously threaten their survival. Alternatively, they might be able to compensate by calling during quiet periods or by making longer calls. Killer whales in three British Columbia pods (whale groups) made longer calls when surrounded by boats of whale watchers than when left in peace, which suggests that they struggle to communicate above the noise.
In addition, noise pollution interferes with feeding. If an animal stops searching for food every time a boat bears down on it, it may soon go hungry. It also affects species more directly if they use sound to hunt. Beaked whales hunt by echolocation in the deep sea. They produce a stream of clicks, made by blowing air through a structure in their blowpipe. The noise is sent through enlarged parts of hearing-sensitive fat in their heads, and they receive echoes back in the flesh beneath their jaws. Beaked whales are particularly fond of squid. Aside from a thin, horny protective covering, squid have a similar consistency to water, which makes them hard to detect from echoes. A Cuvier’s beaked whale that was recorded hunting when there was background noise had less than half the success others had with no sound interference.
1
Sound is one of the most important means of communication for creatures underwater. In the clear water of a coral reef you can see up to 200 feet at most. In muddier waters, visibility can shrink to three feet. But sound travels far and fast in the sea. Thus many marine animals are dependent on hearing for various purposes. Some whales and dolphins use echolocation(locating objects by reflected sound) for navigation. Male toadfish attract females by buzzing. But background noise from sources such as boat engines can mask familiar sounds and make life more dangerous. When captive toadfish were played ferryboat sounds in a 2005 experiment, they had trouble hearing one another. Since the nineteenth century, boat noise has grown relentlessly, following global economic growth. Of goods traded internationally, 80 percent are shipped by sea. As trade volumes increase, so does noise.
The word “relentlessly” in the passage is closest in meaning to
Vocabulary Questions词汇题
Apersistently
Bunexpectedly
Cperiodically
Denormously
2
Sound is one of the most important means of communication for creatures underwater. In the clear water of a coral reef you can see up to 200 feet at most. In muddier waters, visibility can shrink to three feet. But sound travels far and fast in the sea. Thus many marine animals are dependent on hearing for various purposes. Some whales and dolphins use echolocation(locating objects by reflected sound) for navigation. Male toadfish attract females by buzzing. But background noise from sources such as boat engines can mask familiar sounds and make life more dangerous. When captive toadfish were played ferryboat sounds in a 2005 experiment, they had trouble hearing one another. Since the nineteenth century, boat noise has grown relentlessly, following global economic growth. Of goods traded internationally, 80 percent are shipped by sea. As trade volumes increase, so does noise.
According to paragraph 1, some marine animals rely on their sense of hearing to do which TWO of the following? To receive full credit, you must select TWO answer choices.
Factual Information Questions事实信息题
Select 2 answers
AFind a better habitat
BGet away from predators
CFind their way from place to place
DObtain mates
3
Sound is one of the most important means of communication for creatures underwater. In the clear water of a coral reef you can see up to 200 feet at most. In muddier waters, visibility can shrink to three feet. But sound travels far and fast in the sea. Thus many marine animals are dependent on hearing for various purposes. Some whales and dolphins use echolocation(locating objects by reflected sound) for navigation. Male toadfish attract females by buzzing. But background noise from sources such as boat engines can mask familiar sounds and make life more dangerous. When captive toadfish were played ferryboat sounds in a 2005 experiment, they had trouble hearing one another. Since the nineteenth century, boat noise has grown relentlessly, following global economic growth. Of goods traded internationally, 80 percent are shipped by sea. As trade volumes increase, so does noise.
In paragraph 1, why does the author provide the information that 80 percent of goods in international trade are shipped by sea?
Factual Information Questions事实信息题
ATo provide data that shows that trade volumes continue to increase
BTo explain why boat noise is an increasing problem for marine animals
CTo suggest that transportation of goods by water is more efficient than by land
DTo indicate that the increased number of commercial boats has reduced underwater visibility for marine animals
4
The much greater density of seawater carries sounds farther and faster than air. Noise travels about five times more quickly in the sea, reaching 5,000 feet per second in temperate waters. It drops off less quickly in water than in air, so noises can be heard at far greater distances. Higher pitched noises have higher frequency, and lower pitched noises have lower frequency. High frequencies weaken more quickly than low frequencies, so deep notes go farther, as shown by the fact that some of the great whales communicate over hundreds or even thousands of miles using low frequency rumbles(thunder-like sounds). Sounds go farthest of all if animals take advantage of a strange attribute of the sea. Between the warm lighter layer at the surface and the cool dense water below there is a narrow region where sounds travel in a similar way to light in a fiber-optic cable. Differences in density across this boundary-the thermocline-keep sound waves produced there in a narrow channel, where they lose little energy as they travel. Before the days of satellite beacons the United States Navy issued pilots with an explosive charge. If they had to make an emergency landing in the sea, they were to lower the charge on a string and explode it in this sound-carrying channel. The sound would carry to sensors perhaps thousands of miles away, where the location of the pilot could be determined.
Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.
Sentence Simplification Questions句子简化题
ADifferent kinds of whales make sounds of different frequencies. allowing some whales to communicate across larger distances than others.
BThunder-like sounds that are low in frequency are more useful to whales in comparison to high-frequency sounds.
CWhales that produce sounds with high frequencies communicate better than other whales do.
DBecause low-frequency sounds go farther than high-frequency sounds,some whales can communicate over vast distances with low, thunder-like sounds.
5
The much greater density of seawater carries sounds farther and faster than air. Noise travels about five times more quickly in the sea, reaching 5,000 feet per second in temperate waters. It drops off less quickly in water than in air, so noises can be heard at far greater distances. Higher pitched noises have higher frequency, and lower pitched noises have lower frequency. High frequencies weaken more quickly than low frequencies, so deep notes go farther, as shown by the fact that some of the great whales communicate over hundreds or even thousands of miles using low frequency rumbles(thunder-like sounds). Sounds go farthest of all if animals take advantage of a strange attribute of the sea. Between the warm lighter layer at the surface and the cool dense water below there is a narrow region where sounds travel in a similar way to light in a fiber-optic cable. Differences in density across this boundary-the thermocline-keep sound waves produced there in a narrow channel, where they lose little energy as they travel. Before the days of satellite beacons the United States Navy issued pilots with an explosive charge. If they had to make an emergency landing in the sea, they were to lower the charge on a string and explode it in this sound-carrying channel. The sound would carry to sensors perhaps thousands of miles away, where the location of the pilot could be determined.
The word “attribute” in the passage is closest in meaning to
Vocabulary Questions词汇题
Amystery
Bcharacteristic
Cirregularity
Dregion
6
The much greater density of seawater carries sounds farther and faster than air. Noise travels about five times more quickly in the sea, reaching 5,000 feet per second in temperate waters. It drops off less quickly in water than in air, so noises can be heard at far greater distances. Higher pitched noises have higher frequency, and lower pitched noises have lower frequency. High frequencies weaken more quickly than low frequencies, so deep notes go farther, as shown by the fact that some of the great whales communicate over hundreds or even thousands of miles using low frequency rumbles(thunder-like sounds). Sounds go farthest of all if animals take advantage of a strange attribute of the sea. Between the warm lighter layer at the surface and the cool dense water below there is a narrow region where sounds travel in a similar way to light in a fiber-optic cable. Differences in density across this boundary-the thermocline-keep sound waves produced there in a narrow channel, where they lose little energy as they travel. Before the days of satellite beacons the United States Navy issued pilots with an explosive charge. If they had to make an emergency landing in the sea, they were to lower the charge on a string and explode it in this sound-carrying channel. The sound would carry to sensors perhaps thousands of miles away, where the location of the pilot could be determined.
According to paragraph 2, why is the thermocline so effective in carrying sound waves over long distances?
Factual Information Questions事实信息题
AThe thermocline usually is not disturbed by the presence of marine-animal habitats.
BThe water along the thermocline is warmer than the water both above and below it.
CThe sound waves produced in the thermocline do not weaken very much as they travel.
DThe thermocline is deep enough to be unaffected by sound waves coming from the surface.
7
Because most animals can only hear over a limited frequency range, the effect of noise on animals also depends on its frequency. The continuous low-frequency sounds produced by human activities in the sea overlap pretty closely with the hearing ranges of fish and whales. There are signs that some try to compensate. Northern right whales call louder when there is background boat noise. The more noise there is, the louder they call. They also call about eight tones higher than they did in the 1950s, probably in an effort to be heard above the low-frequency drone of engines. But there is a limit to how loud they can call. As noise levels continue to rise, whales will become increasingly isolated. Since there are fewer than 400 northern right whales left, isolation could seriously threaten their survival. Alternatively, they might be able to compensate by calling during quiet periods or by making longer calls. Killer whales in three British Columbia pods (whale groups) made longer calls when surrounded by boats of whale watchers than when left in peace, which suggests that they struggle to communicate above the noise.
Which of the following can be inferred from paragraph 3 about why northern right whales may not survive?
Inference Questions推理题
AIncreased sea noise prevents them from communicating with other whales.
BTheir habitat is being taken over by killer whales.
CIncreased sea noise causes their usual prey to move away to quieter areas of the ocean.
DTheir louder calling to overcome increased sea noise warns prey of their presence.
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In addition, noise pollution interferes with feeding. If an animal stops searching for food every time a boat bears down on it, it may soon go hungry. It also affects species more directly if they use sound to hunt. Beaked whales hunt by echolocation in the deep sea. They produce a stream of clicks, made by blowing air through a structure in their blowpipe. The noise is sent through enlarged parts of hearing-sensitive fat in their heads, and they receive echoes back in the flesh beneath their jaws. Beaked whales are particularly fond of squid. Aside from a thin, horny protective covering, squid have a similar consistency to water, which makes them hard to detect from echoes. A Cuvier’s beaked whale that was recorded hunting when there was background noise had less than half the success others had with no sound interference.
What kind of evidence does the author cite to support the statement that “noise pollution interferes with feeding”?
Factual Information Questions事实信息题
AThe lack of squid living in areas where whales typically hunt
BChanges in the sounds made by some whales’ prey
COne whale’s rate of hunting success
DA change in the way one type of whale searched for food
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The much greater density of seawater carries sounds farther and faster than air. Noise travels about five times more quickly in the sea, reaching 5,000 feet per second in temperate waters. It drops off less quickly in water than in air, so noises can be heard at far greater distances. Higher pitched noises have higher frequency, and lower pitched noises have lower frequency. High frequencies weaken more quickly than low frequencies, so deep notes go farther, as shown by the fact that some of the great whales communicate over hundreds or even thousands of miles using low frequency rumbles(thunder-like sounds). Sounds go farthest of all if animals take advantage of a strange attribute of the sea. [■]Between the warm lighter layer at the surface and the cool dense water below there is a narrow region where sounds travel in a similar way to light in a fiber-optic cable. [■]Differences in density across this boundary-the thermocline-keep sound waves produced there in a narrow channel, where they lose little energy as they travel. [■]Before the days of satellite beacons the United States Navy issued pilots with an explosive charge.[■] If they had to make an emergency landing in the sea, they were to lower the charge on a string and explode it in this sound-carrying channel. The sound would carry to sensors perhaps thousands of miles away, where the location of the pilot could be determined.
Look at the four squaresthat indicate where the following sentence could be added to the passage
Humans, too, have taken advantage of this.
Insert Text Questions句子插入题
Where would the sentence best fit？Click on a square sentence to the passage.
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Many marine animals rely on their sense of hearing to perform important life functions.
Prose Summary Questions概要小结题
Select 3 answers
AThe increase of ocean trade since the nineteenth century has also increased noise that interferes with the well-being of sea animals.
BAttempts by the operators of whale-watching boats to reduce noise have made matters worse by merely lowering frequencies and thus increasing overlap.
CSome sea animals, like whales, have adjusted their calls in an attempt to overcome interference from human-created ocean noises.
DSome sea animals are able to escape the worst effects of boat noise by staying inside a narrow channel between warm and cool layers of the ocean.
ECertain whales have evolved structural adaptations that allow them to locate prey in spite of the interference of ocean noise.
FExcessive underwater noise can prevent sea animals that hunt by echolocation from obtaining enough food.
