听力文本

This is Scientific American — 60-Second Science. I'm Emily Schwing.
When you look at satellite images it's easy to pick out hurricanes, deserts, and the work of a certain semiaquatic rodent:
"And the reason you can see beaver activity from space is because they leave a mark on the landscape."
Ken Tape is an Arctic Ecologist at the University of Alaska Fairbanks.
"So they make these ponds, and when a pond forms my idea was that we could infer, if it was a certain kind of pond and we could see a beaver dam, then we could infer that beavers had moved into that area, or moved out of that area if it's a beaver pond that's drained."
Tape and a team of other scientists used Landsat satellite images that cover more than 19,000 square kilometers of Arctic tundra in Alaska.
"We saw lots of new beaver ponds, I think we saw 56 new beaver ponds formed between 1999 and 2014."

Beavers are considered keystone species, which have an outsized effect on their ecosystem.
"And I think it's particularly true in the Arctic because it's underlain by all this frozen ground."
He's talking about permafrost.
"And what happens is when you start flooding permafrost areas, permafrost starts to deteriorate. And really the glue that's binding the soil together, that's holding the landscape together starts to thaw."
Tape and colleagues presented their findings December 11th at the annual conference of the American Geophysical Union. He says the implications of beavers' northward expansion are big.
"Imagine that you just dropped 56 groundwater springs into Arctic stream environments. A groundwater spring in the Arctic is a rare thing in the Arctic and it's an oasis of biologic activity for fish spawning and things like that."
Beavers may be following the northward expansion of vegetation onto the tundra.
"But the other possible driver is rebound from heavy trapping a century ago."
If they contribute to the deterioration of the permafrost, you could call it coming back with a vengeance.
Thanks for listening the Scientific American — 60-Second Science. I'm Emily Schwing.

参考译文

这里是科学美国人——60秒科学J&(4LOlFqD4d。我是埃米莉·施温W4&[^6R..H#。
你在看卫星图片时，很容易辨别出飓风、沙漠以及某种半水生啮齿动物的杰作：
“你能从太空看到海狸活动的原因是，它们在地球景观上留下了印记w_Upofnef_FW。”
阿拉斯加费尔班克斯大学的北极生态学家肯·泰普说道7qW4uIVh7Xd^jA.]cj。
“海狸建造了这些池塘，当一个池塘形成时，我们可以进行推断，如果那是某种类型的池塘，而且我们还能看到海狸水坝，那我们就可以推断出，海狸迁入了这一区域，如果海狸池塘干涸了，那就说明海狸已经离开了那个区域7,A=dRrTAELnM,WZI。”
泰普和一个科学家团队使用了地球资源卫星图片，这些图片拍摄了阿拉斯加北极冻原超过1.9万平方公里的地区yXZ0siSpx+OA。
“我们看到了很多新的海狸池塘，我认为有56个新海狸池塘形成于1999年至2004年间i-3=uNOkQec。”
海狸被认为是关键种，对所处生态系统有重大影响RlN0wwJ7HF^]S(=!vLxY。
“我认为海狸对北极地区的影响尤为重要，因为北极地下全是这种冻土%SKVHOMQ)UrUy。”
泰恩指的是永久冻土ON-R.,9Rl7&9]。
“永久冻土区被水淹没后会开始解冻O&.KF#(Li2Ko_hZ。也就是说，粘合土壤、连接地形的胶开始溶解7m|uw5~FG&.8-3p2|m。”
在12月11日举行的美国地球物理学会会议上，泰普和同事展示了他们的研究结果uWPEex-3nK0l+UB。泰普表示，海狸向北扩张有重大影响~+Nd5fxmwwkU7i6x。
“想象一下，在北极河流环境中放入56个潜水泉1NqifnGl55cH7。潜水泉在北极很罕见，它是鱼类产卵等生物活动的乐土C&Jw98_c=TuK)zEq。”
海狸可能是在追随冻原植被向北扩展的脚步;_Es|8~g;C|^PFayT。
“而另一种可能的驱动因素是100年前人们大肆捕捉海狸的反作用%UQ_SHS+6(re。”
如果海狸使永久冻土解冻，那可以说它们回来复仇了^|%pXc3&+a^7*YOz!z)I。
谢谢大家收听科学美国人——60秒科学j%ofb.0#NcP。我是埃米莉·施温=3u!9tZcH3。

译文为可可英语翻译，未经授权请勿转载！

重点讲解

重点讲解：
1. pick out 辨认出；分辨出；
例句：The detective-constable picked out the words with difficulty.
探警费力地辨认出这些文字|-CJJkfH*|SfX)Bt.JT&。
2. lots of 许多；很多；大量；
例句：We took lots of measurements.
我们得到了许多测量结果M@m;S#J5.]j4。
3. contribute to 促成；促使；是导致…的原因之一；
例句：There is no doubt that these measures will contribute to the solution of the problem.
毫无疑问这些措施将会有助于解决这个问题GsBq(1tv_nPV9Y_6y#。
4. come back 回来，回去；
例句：She's going to come back every so often.
她会偶尔回来的Mg[-fE4zsdbbCSz^]BD。