VOA标准英语2015--科学家寻找更好的途径解决鲨鱼面临的威胁
时间：2019-01-14 作者：英语课 分类：VOA标准英语2015年(二月)
Scientists Seek Better Understanding of Threats Faced by Sharks 科学家寻找更好的途径解决鲨鱼面临的威胁
With many shark species endangered or threatened as a result of pollution and other problems, scientists are getting a shark’s-eye view of their environment to better understand the dangers they face.
A University of Hawaii research site on Coconut Island, minutes by motorboat from the shore of Oahu, is a good place to observe sharks, since they’re native to local waters. Some are kept in a sheltered bay for study.
Carl Meyer does research on "when sharks are feeding and hopefully how much they’re eating. That’s what we use these captive animals for.”
Scientists also monitor the behavior of sharks at sea, placing sensing pellets in their food to monitor digestion 2, measuring the animals and then releasing them with radio-equipped electronic tags attached to their fins 3. The researchers study tiger sharks, sandbar sharks, blacktip sharks and others, and they recently fitted a sandbar shark with a camera for a rare shark’s-eye view of its daily activities.
“When we recovered the camera," Meyer said, "we saw that the shark had spent the day in a large aggregation 4 of sharks, not just sandbar sharks but also blacktip sharks and many, many scalloped hammerhead sharks.”
Sharks are swift and lethal 5, but don’t usually prey 6 on humans. Meyer said the rare attacks are amplified 7 by the media and dramatized in films like the 1975 thriller 8 "Jaws 9."
He said sharks are important top-level predators 10 that help maintain the balance of the marine 11 systems. Those systems are threatened by pollution, climate change and commercial fishing, as fishermen target sharks for the Asian food market and kill them in the process of harvesting other species.
Meyer said humans are more of a risk to sharks than sharks are to humans.
"Never before in the natural history of the world have we seen a species become so dominant 12 and so able to alter the natural environment,” he said.
And the results of those environmental changes cannot always be predicted, he said.
- The husk of this coconut is particularly strong.椰子的外壳很明显非常坚固。
- The falling coconut gave him a terrific bang on the head.那只掉下的椰子砰地击中他的脑袋。
- This kind of tea acts as an aid to digestion.这种茶可助消化。
- This food is easy of digestion.这食物容易消化。
- The level of TNF-α positively correlated with BMI,FPG,HbA1C,TG,FINS and IRI,but not with SBP and DBP. TNF-α水平与BMI、FPG、HbA1C、TG、FINS和IRI呈显著正相关，与SBP、DBP无相关。 来自互联网
- Fins are a feature specific to fish. 鱼鳍是鱼类特有的特征。 来自辞典例句
- A high polymer is a very large aggregation of units.一个高聚物是许多单元的非常大的组合。
- Moreover,aggregation influences the outcome of chemical disinfection of viruses.此外，聚集作用还会影响化学消毒的效果。
- A hammer can be a lethal weapon.铁锤可以是致命的武器。
- She took a lethal amount of poison and died.她服了致命剂量的毒药死了。
- Stronger animals prey on weaker ones.弱肉强食。
- The lion was hunting for its prey.狮子在寻找猎物。
- He amplified on his remarks with drawings and figures. 他用图表详细地解释了他的话。
- He amplified the whole course of the incident. 他详述了事件的全过程。
- He began by writing a thriller.That book sold a million copies.他是写惊险小说起家的。那本书卖了一百万册。
- I always take a thriller to read on the train.我乘火车时，总带一本惊险小说看。
- The antelope could not escape the crocodile's gaping jaws. 那只羚羊无法从鱷鱼张开的大口中逃脱。
- The scored jaws of a vise help it bite the work. 台钳上有刻痕的虎钳牙帮助它紧咬住工件。
- birds and their earthbound predators 鸟和地面上捕食它们的动物
- The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》
- 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。