英语翻译It is hard to track the blue whale,which has almost been

英语翻译
It is hard to track the blue whale,which has almost been killed off by commercial whaling.Attaching radio devices to it is difficult and visual sightings are too unreliable to give real insight into its behavior.So biologists were delighted early this year when,with the help of the US Navy,they ere able to track a particular blue whale for 43 days recording its sounds.This was possible because of the Navy's formerly top secret system of underwater listening devices across the oceans.Tracking whales is but one example of an exciting new world just opening to civilian scientists after the cold war as the Navy starts to share and partly uncover its global network f underwater listening system built over the decades to track the ships of potential enemies.Earth scientists announced at a news conference recently that they had used the system for closely observing a deep-sea volcanic eruption for the first time and that they planned similar studies.Other scientists have proposed to use the network for tracking ocean currents and measuring changes in the ocean and global temperatures.Different layers of ocean water can act as channels for sounds focusing them in the same way a stethoscope (听诊器) does when it carries faint noises from a patient's chest to a doctor's ear.This focusing is the main reason that even relatively weak sounds in the ocean,especially low-frequency ones,can often travel thousands of miles.

目前很难追踪因商业捕捞而日渐绝迹的蓝鲸.同时也很难将无线电装置安装在它身上,目视观察也同样无法让我们直正了解它们的习性.因此在今年的早些时候,在美国海军的协助下,生物学家很高兴地发现他们可以追踪一只蓝鲸长达43天之久以录取它的声音.这一些都归功于美国海军之前采用的跨洋绝密水下监听设备.自冷战结束后,美国海军已开始分享并部分公开其在几十年前建成的用于监测潜在敌人的全球监测网络,这使得众多从事民用科技研究的科学家有机会进入一个全新的领域,
追踪蓝鲸只不过是这其中的一个事例而已.地球科学家在新近召开的一次会议上宣称,他们通过使用该监测系统首次严密观测了一次深海火山喷发并计划进行相类似课题的研究工作.其它的科学家也建议使用该网络追踪洋流并测量海洋与全球温度的变化情况.不同层次的洋流都可起到将声音集中的作用.如听诊器将病人胸腔中微弱的噪音传到医生耳中一样.这种集声效应是相应微声,特别是低频噪声可在洋流中传输数千英里的主要原因.