Seismic bangs 'block' whale calls 人类活动影响鲸鱼生存
文章来源:未知 文章作者:meng 发布时间:2009-09-24 03:26 字体: [ ]  进入论坛
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Scientists have turned up new evidence showing that ocean noise can affect the communication of whales.

科学家发现新证据显示深海噪音可以影响鲸的沟通。

Blue whales were hunted to the <a href=brink1 of extinction2 in the last century" width="226" border="0" src="/upimg/090924/4_054529_1.jpg" />
Blue whales were hunted to the brink of extinction in the last century

Studying blue whales off the eastern Canadian coast, they found the animals changed their vocalisations in response to an underwater seismic3 survey(地震勘测).

The survey was conducted using gear considered to have a low impact.

Writing in the journal Biology Letters, the researchers say this is the first evidence that whales will increase calls in response to underwater noise.

At this site, on a feeding ground, the whales make frequent calls of just a few seconds' duration, rather than the long "songs" that can be heard across vast tracts4 of ocean.

"The calls are used for short-range communication within a range of a few hundred metres," said Lucia Di Iorio, based at the University of Zurich in Switzerland.

"And the frequency band they use is exactly where the main energy of those seismic pulses is located," she told BBC News.

Initially5, Dr Di Iorio's group tried to persuade the Canadian university conducting the seismic survey to co-operate in the research, and to give details of where and when the underwater bangs were being produced.

That attempt failing, the scientists recorded the pulses with an array of detectors6 mounted on the sea bed in the St Lawrence Estuary7.

The detectors also recorded the blue whales' calls, which are thought to be associated with feeding and socialising.

Information gap

On days with seismic surveys, the whales made two-and-half-times more calls than on days without.

The ratio was the same when the recordings8 were analysed in blocks of 10 minutes; survey noise induced more than a doubling of calls.

The researchers suggest the whales are having to "repeat information", as some of the calls are blocked or degraded by the seismic bangs.

"Our research doesn't say anything about whether this increase in call rate is negative for the animals, but of course it's not positive and it may be stressful," said Dr Di Iorio.

This survey was carried out using "sparkers", devices that generate a bang from an electrical discharge between two electrodes.

Sparkers produce sounds quieter than the ones generated by airguns, another technique engineers use for underwater surveys.

"It's used [here] because it's thought to have a lower impact on marine9 life(海洋生物)," said Dr Di Iorio.

"But we should definitely reconsider these things, because clearly it's not only the sound level that's important; and one thing might be not to do the test when there are lots of whales around."

Gray area

A number of recent reports have highlighted the increase in ocean noise brought about by humanity's use of the oceans, in particular shipping10.

One study indicated that the level of background noise from ships' propellers11(螺旋桨) was doubling every decade in the Pacific Ocean.

Conservation groups are raising the issue because many marine animals, including whales and dolphins, use sound to communicate and to hunt.

The sharp sounds of seismic surveys are a particular concern. Engineers use very sharp, very loud bangs because these produce the clearest images of geological structures below the sea floor.

The surveys are typically used to map oil and gas deposits.

Earlier this year, companies involved in the Sakhalin Energy consortium(联合,合伙) agreed to suspend seismic work after seeing evidence that it was driving the critically endangered western gray whale, of which only about 130 remain, away from its summer feeding ground.



点击收听单词发音收听单词发音  

1 brink OWazM     
n.(悬崖、河流等的)边缘,边沿
参考例句:
  • The tree grew on the brink of the cliff.那棵树生长在峭壁的边缘。
  • The two countries were poised on the brink of war.这两个国家处于交战的边缘。
2 extinction sPwzP     
n.熄灭,消亡,消灭,灭绝,绝种
参考例句:
  • The plant is now in danger of extinction.这种植物现在有绝种的危险。
  • The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。
3 seismic SskyM     
a.地震的,地震强度的
参考例句:
  • Earthquakes produce two types of seismic waves.地震产生两种地震波。
  • The latest seismic activity was also felt in northern Kenya.肯尼亚北部也感觉到了最近的地震活动。
4 tracts fcea36d422dccf9d9420a7dd83bea091     
大片土地( tract的名词复数 ); 地带; (体内的)道; (尤指宣扬宗教、伦理或政治的)短文
参考例句:
  • vast tracts of forest 大片大片的森林
  • There are tracts of desert in Australia. 澳大利亚有大片沙漠。
5 initially 273xZ     
adv.最初,开始
参考例句:
  • The ban was initially opposed by the US.这一禁令首先遭到美国的反对。
  • Feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。
6 detectors bff80b364ed19e1821aa038fae38df83     
探测器( detector的名词复数 )
参考例句:
  • The report advocated that all buildings be fitted with smoke detectors. 报告主张所有的建筑物都应安装烟火探测器。
  • This is heady wine for experimenters using these neutrino detectors. 对于使用中微子探测器的实验工作者,这是令人兴奋的美酒。 来自英汉非文学 - 科技
7 estuary ynuxs     
n.河口,江口
参考例句:
  • We live near the Thames estuary.我们的住处靠近泰晤士河入海口。
  • The ship has touched bottom.The estuary must be shallower than we thought.船搁浅了。这河口的水比我们想像的要浅。
8 recordings 22f9946cd05973582e73e4e3c0239bb7     
n.记录( recording的名词复数 );录音;录像;唱片
参考例句:
  • a boxed set of original recordings 一套盒装原声录音带
  • old jazz recordings reissued on CD 以激光唱片重新发行的老爵士乐
9 marine 77Izo     
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。
10 shipping WESyg     
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。
11 propellers 6e53e63713007ce36dac451344bb87d2     
n.螺旋桨,推进器( propeller的名词复数 )
参考例句:
  • The water was thrashing and churning about under the propellers. 水在螺旋桨下面打旋、翻滚。 来自辞典例句
  • The ship's propellers churned the waves to foam. 轮船的推进器将海浪搅出泡沫。 来自辞典例句
TAG标签: ocean noise whale seismic
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