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英语听力:自然百科 马蹄蟹与漂鷸(二)

时间:2014-04-29 03:49来源:互联网 提供网友:gmeng   字体: [ ]
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    (单词翻译:双击或拖选)

 We are not the only species that's come to dependent on the horseshoe crab1, they're critical to others too, like the Red Knot.

 
It's now May in Brazil, the Red Knots have built up their fat reserves and they are now in their breeding plumage. They are ready to begin of longest legs of their epic2 journey. They'll fly for as many as four days and nights without stopping, mostly over Open Ocean, with no landmarks3 to guide them. They'll use the moon, the stars and the sun. Their departure is mysteriously synchronized4 with an annual event, 4,000 miles north.
 
Here on the Delaware Bay, the water has warmed and the world's largest population of horseshoe crabs5 is beginning to spawn6. It's here that the Red Knot has always found the fuel for their journey to the Arctic, and the horseshoe crab has always provided that fuel in the form of eggs. The spawning7 season is an annual feast. It's a windfall for shorebirds, and a great opportunity for biologists. Migrating flocks have just begun to arrive. If the Red Knot's on schedule, they should be here soon.
 
Horseshoe crabs prefer spawning at the cover of night, but this is the height of their short season. It only lasts for few weeks. They come to shore when the tides are highest to lay their eggs deep in sand. Swarmed8 by hopeful males, the female digs down to bury her clutch. The males are smaller than the females, but they have a special claw that hooks on to her shell. Since fertilization is external, even unattached males would father some of the eggs. When her clutches are finally laid, the females break through the sand. In all the commotion9, eggs from prior spawns10 get unearthed11. What the crab accidently dig up is what the Red Knots depend on.
 
As the tide recedes12 and the crabs retreat, a flock of Red Knots appears in the sky. They've traveled for four days and nights without stopping. They're exhausted13 and initiated14. The flock will find a safe place to roost for the night and rest.
 
From all over the world, biologists have come to count shorebirds on the Delaware Bay. The spring migration15 offers a rare opportunity to assess populations. Many species of shorebirds are in decline, but the Red Knots that winter in South America are by far the most seriously. No one knows how many will make it to the Bay this year.
 
For the next week, more flocks of red knots trickle16 in. Once they're here, they need to eat. They only have about two weeks to refuel and set off again. Their breeding is tightly synchronized with the brief Artic summer. Their digestive system has shut down for the long journey. It's here that the horseshoe crab makes all the difference in the world. Their soft eggs are packed with protein and easy to digest. Some knots will double their weight in two weeks. While it's important food for other species, for the Red Knot it's essential.
 
This was a revelation to scientists and a key piece of the puzzle. As Red Knot numbers dropped, evidence began pointing to the Delaware Bay and to horseshoe crab eggs. Ongoing17 studies began to confirm the connection. There's been a steady decline in eggs on the Bay. Figuring out how many eggs there are is a tedious job, but it's become a critical piece in the puzzle.
 
That's a lot of work. We work about 40 hours a week. We take a sample roughly per one meter and we'll do this for about four hours other couple of days, then we're sought to eggs, then we count the eggs and that takes six or seven hours, and then we count the birds. From last year, it looks like the egg densities18 have dropped from same beaches and it's not a good sign. In Delaware in May, it's just a beautiful animal. I mean, it is, oh, I hate to see some go extinct.

点击收听单词发音收听单词发音  

1 crab xoozE     
n.螃蟹,偏航,脾气乖戾的人,酸苹果;vi.捕蟹,偏航,发牢骚;vt.使偏航,发脾气
参考例句:
  • I can't remember when I last had crab.我不记得上次吃蟹是什么时候了。
  • The skin on my face felt as hard as a crab's back.我脸上的皮仿佛僵硬了,就象螃蟹的壳似的。
2 epic ui5zz     
n.史诗,叙事诗;adj.史诗般的,壮丽的
参考例句:
  • I gave up my epic and wrote this little tale instead.我放弃了写叙事诗,而写了这个小故事。
  • They held a banquet of epic proportions.他们举行了盛大的宴会。
3 landmarks 746a744ae0fc201cc2f97ab777d21b8c     
n.陆标( landmark的名词复数 );目标;(标志重要阶段的)里程碑 ~ (in sth);有历史意义的建筑物(或遗址)
参考例句:
  • The book stands out as one of the notable landmarks in the progress of modern science. 这部著作是现代科学发展史上著名的里程碑之一。 来自《现代汉英综合大词典》
  • The baby was one of the big landmarks in our relationship. 孩子的出世是我们俩关系中的一个重要转折点。 来自辞典例句
4 synchronized f6dbc93312ac2dd66d3989fc9050167f     
同步的
参考例句:
  • Do not use the synchronized keyword in Managed Objects. 不要在管理对象上使用synchronized关键字。 来自互联网
  • The timing of the gun was precisely synchronized with the turning of the plane's propeller. 风门的调速与飞机螺旋桨的转动精确同步。 来自辞典例句
5 crabs a26cc3db05581d7cfc36d59943c77523     
n.蟹( crab的名词复数 );阴虱寄生病;蟹肉v.捕蟹( crab的第三人称单数 )
参考例句:
  • As we walked along the seashore we saw lots of tiny crabs. 我们在海岸上散步时看到很多小蟹。 来自《简明英汉词典》
  • The fish and crabs scavenge for decaying tissue. 鱼和蟹搜寻腐烂的组织为食。 来自《简明英汉词典》
6 spawn qFUzL     
n.卵,产物,后代,结果;vt.产卵,种菌丝于,产生,造成;vi.产卵,大量生产
参考例句:
  • The fish were madly pushing their way upstream to spawn.鱼群为产卵而疯狂地向上游挤进。
  • These fish will lay spawn in about one month from now.这些鱼大约一个月内会产卵。
7 spawning e223115a66b2213a16c438abb9a400cb     
产卵
参考例句:
  • Encounter sites have a small chance of spawning a "Commander" NPC. 遭遇战地区有很小的几率遇到NPC指挥官。
  • Instantly revives your Champion at your Spawning Pool, 9 minute cooldown. 立即在出生地复活你的英雄,冷却时间9分钟。
8 swarmed 3f3ff8c8e0f4188f5aa0b8df54637368     
密集( swarm的过去式和过去分词 ); 云集; 成群地移动; 蜜蜂或其他飞行昆虫成群地飞来飞去
参考例句:
  • When the bell rang, the children swarmed out of the school. 铃声一响,孩子们蜂拥而出离开了学校。
  • When the rain started the crowd swarmed back into the hotel. 雨一开始下,人群就蜂拥回了旅社。
9 commotion 3X3yo     
n.骚动,动乱
参考例句:
  • They made a commotion by yelling at each other in the theatre.他们在剧院里相互争吵,引起了一阵骚乱。
  • Suddenly the whole street was in commotion.突然间,整条街道变得一片混乱。
10 spawns f373732b9f0bf3cce005ffa159e1bbb0     
(鱼、蛙等的)子,卵( spawn的名词复数 )
参考例句:
  • Lava Spawns now require 15 attacks to replicate, up from 14. 火人现在需要攻击15下才会分裂,而不是14下。
  • Idleness spawns discontent, whereas overwork leads to mental and physical exhaustion. 懒惰滋生不满,而过度工作导致精神和身体的疲劳。
11 unearthed e4d49b43cc52eefcadbac6d2e94bb832     
出土的(考古)
参考例句:
  • Many unearthed cultural relics are set forth in the exhibition hall. 展览馆里陈列着许多出土文物。
  • Some utensils were in a state of decay when they were unearthed. 有些器皿在出土时已经残破。
12 recedes 45c5e593c51b7d92bf60642a770f43cb     
v.逐渐远离( recede的第三人称单数 );向后倾斜;自原处后退或避开别人的注视;尤指问题
参考例句:
  • For this reason the near point gradually recedes as one grows older. 由于这个原因,随着人渐渐变老,近点便逐渐后退。 来自辞典例句
  • Silent, mournful, abandoned, broken, Czechoslovakia recedes into the darkness. 缄默的、悲哀的、被抛弃的、支离破碎的捷克斯洛伐克,已在黑暗之中。 来自辞典例句
13 exhausted 7taz4r     
adj.极其疲惫的,精疲力尽的
参考例句:
  • It was a long haul home and we arrived exhausted.搬运回家的这段路程特别长,到家时我们已筋疲力尽。
  • Jenny was exhausted by the hustle of city life.珍妮被城市生活的忙乱弄得筋疲力尽。
14 initiated 9cd5622f36ab9090359c3cf3ca4ddda3     
n. 创始人 adj. 新加入的 vt. 开始,创始,启蒙,介绍加入
参考例句:
  • He has not yet been thoroughly initiated into the mysteries of computers. 他对计算机的奥秘尚未入门。
  • The artist initiated the girl into the art world in France. 这个艺术家介绍这个女孩加入巴黎艺术界。
15 migration mDpxj     
n.迁移,移居,(鸟类等的)迁徙
参考例句:
  • Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
  • He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。
16 trickle zm2w8     
vi.淌,滴,流出,慢慢移动,逐渐消散
参考例句:
  • The stream has thinned down to a mere trickle.这条小河变成细流了。
  • The flood of cars has now slowed to a trickle.汹涌的车流现在已经变得稀稀拉拉。
17 ongoing 6RvzT     
adj.进行中的,前进的
参考例句:
  • The problem is ongoing.这个问题尚未解决。
  • The issues raised in the report relate directly to Age Concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。
18 densities eca5c1ea104bef3058e858fe084fb6d0     
密集( density的名词复数 ); 稠密; 密度(固体、液体或气体单位体积的质量); 密度(磁盘存贮数据的可用空间)
参考例句:
  • The range of densities of interest is about 3.5. 有用的密度范围为3.5左右。
  • Densities presumably can be probed by radar. 利用雷达也许还能探测出气体的密度。
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