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Noisy Ships Have Whales Yelling to be Heard
Ferries, freighters and fishing and tour boats are part of the tableau1 that often makes living by the sea postcard-pretty and desirable. But all that maritime2 activity creates cacophony3 underwater - and has conservationists and shippers discussing ways to dial that volume down.
Marine4 scientists at the University of Victoria record sounds through an underwater microphone placed near the shipping5 lanes off Canada's Vancouver Island. To them, it almost sounds like the whales are shouting to be heard over the nearly continuous engine noise.
Can you hear me now?
Michael Jasny, senior policy analyst6 for the Natural Resources Defense7 Council, says this "fog of noise," as he calls it, is impeding8 the ability of whales to communicate.
"Shipping noise falls across the same frequencies that these animals use for all their vital behaviors - for feeding, for finding mates, for avoiding predators9 and for navigating10."
According to Jasny, sound travels very efficiently11 underwater and he's not only worried about marine mammals. "The entire web of life in the oceans depends on sound."
The science in this arena12 is pretty new. Precise boundaries between noisy and quiet, safe and harmful have yet to be established. But Jasny believes the risks can only rise as international trade and offshore13 drilling increase.
"As the research has been done, it's been very clear that what we have on our hands is really a major problem. It's a serious problem. It's global problem. Fortunately, in shipping, we have a problem that has a solution."
And that solution is quieter ship designs. Nearby in Victoria, Canada, several whale-watch companies brag14 that their boats produce less underwater racket. Bigger examples are the newest four vessels15 to join the fleet of the U.S. ocean research agency, NOAA. They're each 63 meters long.
Quieter ships
Michael Bahtiarian, vice16 president of Noise Control Engineering, consulted on their design. "These NOAA ships show that you can get fairly quiet - I think quiet enough - because they are able at 11 knots to go up and count a fish and not startle the fish so they can actually count it."
Bahtiarian points to propellers18 as the primary source of noise pollution. The fix is to match a more efficient propeller17 with an optimized19 hull20 shape. The new federal research ships also have more expensive engines that reduce vibration21.
"People are saying a lot of, ‘Oh boy, here comes something else we have to deal with.' You know, the technology has been around," he says. "It's just technology that we've had in the military realm for a while."
Joint22 effort
Kathy Metcalf, who directs maritime affairs at the Chamber23 of Shipping of America, says the U.S. shipping industry recognizes the potential noise pollution problem and wants to be part of the solution.
"Our approach is that if we're progressive now and begin the changeover in the design of ships before we are forced to do it, it will be much less costly24 to the industry."
And there's one more big selling point.
"If people see the fuel savings25 that we expect to be obtained from this more refined ship design, we don't think you're going to have to sell the concept to anybody," says Metcalf.
She says the best venue26 for working out any new rules for shipping is a United Nations agency called the International Maritime Organization. She estimates that process could take five years. Eventually, other UN groups may be tapped to control other sources of underwater noise, such as offshore oil and gas production or naval27 exercises.
1 tableau | |
n.画面,活人画(舞台上活人扮的静态画面) | |
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2 maritime | |
adj.海的,海事的,航海的,近海的,沿海的 | |
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3 cacophony | |
n.刺耳的声音 | |
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4 marine | |
adj.海的;海生的;航海的;海事的;n.水兵 | |
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5 shipping | |
n.船运(发货,运输,乘船) | |
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6 analyst | |
n.分析家,化验员;心理分析学家 | |
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7 defense | |
n.防御,保卫;[pl.]防务工事;辩护,答辩 | |
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8 impeding | |
a.(尤指坏事)即将发生的,临近的 | |
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9 predators | |
n.食肉动物( predator的名词复数 );奴役他人者(尤指在财务或性关系方面) | |
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10 navigating | |
v.给(船舶、飞机等)引航,导航( navigate的现在分词 );(从海上、空中等)横越;横渡;飞跃 | |
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11 efficiently | |
adv.高效率地,有能力地 | |
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12 arena | |
n.竞技场,运动场所;竞争场所,舞台 | |
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13 offshore | |
adj.海面的,吹向海面的;adv.向海面 | |
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14 brag | |
v./n.吹牛,自夸;adj.第一流的 | |
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15 vessels | |
n.血管( vessel的名词复数 );船;容器;(具有特殊品质或接受特殊品质的)人 | |
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16 vice | |
n.坏事;恶习;[pl.]台钳,老虎钳;adj.副的 | |
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17 propeller | |
n.螺旋桨,推进器 | |
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18 propellers | |
n.螺旋桨,推进器( propeller的名词复数 ) | |
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19 optimized | |
adj.最佳化的,(使)最优化的v.使最优化,使尽可能有效( optimize的过去式和过去分词 ) | |
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20 hull | |
n.船身;(果、实等的)外壳;vt.去(谷物等)壳 | |
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21 vibration | |
n.颤动,振动;摆动 | |
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22 joint | |
adj.联合的,共同的;n.关节,接合处;v.连接,贴合 | |
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23 chamber | |
n.房间,寝室;会议厅;议院;会所 | |
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24 costly | |
adj.昂贵的,价值高的,豪华的 | |
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25 savings | |
n.存款,储蓄 | |
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26 venue | |
n.犯罪地点,审判地,管辖地,发生地点,集合地点 | |
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27 naval | |
adj.海军的,军舰的,船的 | |
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