-
(单词翻译:双击或拖选)
GWEN IFILL: Finally tonight: how climate change may be affecting life in Alaska as we know it and the captivating images we see there, from ice to Marine1 life.
NewsHour science correspondent Miles O'Brien went there to see for himself.
MILES O'BRIEN: Alaska may seem like a place where things don't change very quickly, the natural beauty is set in stone and is as predictable as the caribou2 beside the road.
But make no mistake, things are changing here quickly, and not for the better. Alaska is at the frontier of climate change. Scientists are scrambling3 to try and understand it.
KARL KREUTZ, University of Maine: We know that the Arctic is warming more rapidly than most other places on Earth.
MILES O'BRIEN: To catch up with University of Maine paleoclimatologist Karl Kreutz and his team, we hopped4 on a plane rigged with skis that landed right on the Ruth Glacier5 in the heart of the Denali National Park.
KARL KREUTZ: Most glaciers6 in Alaska are retreating. We'd like to be able to predict with better accuracy of what will happen, but it's hard to imagine a scenario7 there where glaciers will not continue to lose mass in this area. The question is how fast.
MILES O'BRIEN: But the answer is unknowable if they don't know how much ice is here right now.
SETH CAMPBELL, U.S. Army Corps8 of Engineers: To goal of this specific study is to come up with ice depth measurement across the glacier.
MILES O'BRIEN: Kreutz's colleague Seth Campbell is a research geophysicist for the U.S. Army Corps of Engineers. He and University of Maine undergrad Abby Bradford spent long, strenuous9 days on skis towing a ground-penetrating radar10 up, down and across the glacier.
SETH CAMPBELL: The transfer sends a pulse through the cable. The pulse gets sent down through the ice, reflects off the bedrock, returns back to the surface. And it returns and is recorded by this receiver cable.
We know how fast a radio wave travels through the ice, so based on how long it takes it for the signal to be transmitted and received, we can calculate how deep the ice is.
All right, so sample two should come from a depth of 50 centimeters, please.
MILES O'BRIEN: To have complete confidence in the radar data, they dug this pit 11.5-feet deep and had Abby repel11 down to take readings.
MAN: This is great. SEAL Team Six time. Let's go, baby!
MILES O'BRIEN: Dutiful reporter that I am, I went in.
ABIGAIL BRADFORD, University of Maine: So what we're in, this is just one layer, one annual layer. This is this year's snowfall. And then right what we're standing12 on, where this probe stops — it's a bit covered with snow now, but there's an ice layer right there.
MILES O'BRIEN: And you know that's the previous season?
ABIGAIL BRADFORD: That's the previous season, yes.
MILES O'BRIEN: She weighs a fixed13 volume of snow at various depths to determine its density14. The hope is the layering they see in the pit matches the radar returns.
ABIGAIL BRADFORD: There's thousands of glaciers in Alaska, and very few have had data gathered on them. So we're hoping to piece that puzzle together.
MILES O'BRIEN: Getting back to the surface might have been easy for her, but, for me, well, let's just say I didn't score any style points.
Later in camp, Karl Kreutz dug me a shallower pit.
KARL KREUTZ: But, of course, as we're going deeper in this — on this wall, we're going back in time.
MILES O'BRIEN: A thin wall backlit by the sun. The key is the layers of snow and most importantly ice, proof of a melt.
KARL KREUTZ: These layers in the snowpack are very analogous15 to tree rings. All of these, as we go down and go through the layers are going back in time on the glacier, and we get deeper and deeper.
MILES O'BRIEN: Last season, they went much deeper, drilling out this long ice core a few miles away. It is nature's ancient history book for this glacier.
KARL KREUTZ: So, over the past 40 or 50 years, the number of ice layers that have formed each summer has been increasing. And so we interpret that as meaning that the summertime temperatures in this area have gradually been warming over the past couple decades.
MILES O'BRIEN: The vast majority of glacier ice on our planet lies in Greenland and Antarctica, and so it should come as no surprise that's where most of the attention and scientific effort is.
But the people who come here to the mountains and the glaciers say the ice here shouldn't be overlooked.
SETH CAMPBELL: The interesting thing about Alaska is, a lot of the glaciers sit right at a temperature — right at a zero degree temperature. So, small changes in atmospheric16 air temperature can cause drastic changes in ice point.
MILES O'BRIEN: Five hundred and fifty miles north on the sea ice off Barrow, the notion that Alaska rocks at a tipple17 point is not just academic. It's a matter of survival for a proud culture.
The 2005 film "The Eskimo and the Whale" tells the story of the Inupiat people trying to preserve their subsistence whale hunting tradition.
NELSON NUNGASAT, Inupiat Whaler: The ice is shrinking. We have a lot of cracks in the ice, so we have to watch them a lot more. When I was little, these — these ice piles here, they were — they were 10 times bigger.
MILES O'BRIEN: Nelson Nungasat is captain of a whale hunting team. They rely on stable, thick ice to harpoon18 the 25 bowhead whales they're allowed to take each year for food.
Nelson works as a guide and polar bear sentinel for some scientists focused on the sea ice and the other end of the food chain, the tiny light-sensitive organisms that live in the ice.
CRAIG AUMACK, Columbia University: Temperatures effects up here and ice extent up here actually has profound effects on the marine community underneath19 the ice.
MILES O'BRIEN: Marine ecologist Craig Aumack is with Columbia University's Lamont-Doherty Observatory20. He and his team do a lot of coring as well to measure the temperature of the ice at 10-centimeter intervals21. They drop cameras through the holes and take a peek22 underneath.
What do you hope to see?
CRAIG AUMACK: Well, we kind of just look at the bottom to see. So that pigmentation, this is all algae23.
MILES O'BRIEN: During the winter, the algae hibernates24 in the ice, but, in the spring, it blooms and drops into the water. When and how fast that happens depends on how much light gets through the ice. And that is changing as the ice shrinks, gets thinner and is covered by less snow.
CRAIG AUMACK: So what we're really interested in is then finding out what role this material plays in the total diet of these organisms.
It's really hard to understand the impact of the loss of sea ice without actually understanding then what importance it has toward the underlying25 marine systems.
MILES O'BRIEN: Algae is a so-called primary producer, meaning it is foundation for the entire food chain.
Craig's scientific collaborator26 is marine biologist Andy Juhl.
ANDY JUHL, Columbia University: We know it starts out in the ice, it grows in the ice. Then it gets released from the ice. It ends up in the water. Some of it sinks to the bottom. And so the next question is, who's eating it?
MILES O'BRIEN: They analyze27 all manner of small creatures to see what they're eating and, by analyzing28 their tissue, what provides them the most nutrition. As they gather data, they are working their way up the chain. On this day, they netted a jellyfish.
MAN: Jelly.
MILES O'BRIEN: Cause enough for a science nerd happy dance on the ice. But beneath the surface here, there are grave concerns about what happens when the sea ice is dramatically diminished.
ANDY JUHL: Large marine animals, seals and beluga whales and bowhead whales, the polar bears, all of those organisms are here, because it is an incredibly productive environment and therefore can support those really big organisms, because there are a lot of algae at the base of the food chain here.
MILES O'BRIEN: The amount of snowfall, the depth of the ice supports a finely-honed balance that ultimately sustains the top of the food chain. Here, a single degree of change across the line between ice and water is changing everything.
Miles O'Brien, the "PBS NewsHour," Barrow, Alaska.
点击
收听单词发音
收听单词发音 |
1
marine
|
|
| adj.海的；海生的；航海的；海事的；n.水兵 | |
参考例句： |
|
|
|
|
2
caribou
|
|
| n.北美驯鹿 | |
参考例句： |
|
|
|
|
3
scrambling
|
|
| v.快速爬行( scramble的现在分词 )；攀登；争夺；（军事飞机）紧急起飞 | |
参考例句： |
|
|
|
|
4
hopped
|
|
| 跳上[下]( hop的过去式和过去分词 )； 单足蹦跳； 齐足（或双足）跳行； 摘葎草花 | |
参考例句： |
|
|
|
|
5
glacier
|
|
| n.冰川，冰河 | |
参考例句： |
|
|
|
|
6
glaciers
|
|
| 冰河，冰川( glacier的名词复数 ) | |
参考例句： |
|
|
|
|
7
scenario
|
|
| n.剧本，脚本；概要 | |
参考例句： |
|
|
|
|
8
corps
|
|
| n.(通信等兵种的)部队；(同类作的)一组 | |
参考例句： |
|
|
|
|
9
strenuous
|
|
| adj.奋发的，使劲的；紧张的；热烈的，狂热的 | |
参考例句： |
|
|
|
|
10
radar
|
|
| n.雷达，无线电探测器 | |
参考例句： |
|
|
|
|
11
repel
|
|
| v.击退，抵制，拒绝，排斥 | |
参考例句： |
|
|
|
|
12
standing
|
|
| n.持续，地位；adj.永久的，不动的，直立的，不流动的 | |
参考例句： |
|
|
|
|
13
fixed
|
|
| adj.固定的，不变的，准备好的；(计算机)固定的 | |
参考例句： |
|
|
|
|
14
density
|
|
| n.密集，密度，浓度 | |
参考例句： |
|
|
|
|
15
analogous
|
|
| adj.相似的；类似的 | |
参考例句： |
|
|
|
|
16
atmospheric
|
|
| adj.大气的，空气的；大气层的；大气所引起的 | |
参考例句： |
|
|
|
|
17
tipple
|
|
| n.常喝的酒；v.不断喝，饮烈酒 | |
参考例句： |
|
|
|
|
18
harpoon
|
|
| n.鱼叉；vt.用鱼叉叉，用鱼叉捕获 | |
参考例句： |
|
|
|
|
19
underneath
|
|
| adj.在...下面，在...底下；adv.在下面 | |
参考例句： |
|
|
|
|
20
observatory
|
|
| n.天文台，气象台，瞭望台，观测台 | |
参考例句： |
|
|
|
|
21
intervals
|
|
| n.[军事]间隔( interval的名词复数 )；间隔时间；[数学]区间；（戏剧、电影或音乐会的）幕间休息 | |
参考例句： |
|
|
|
|
22
peek
|
|
| vi.偷看，窥视；n.偷偷的一看，一瞥 | |
参考例句： |
|
|
|
|
23
algae
|
|
| n.水藻，海藻 | |
参考例句： |
|
|
|
|
24
hibernates
|
|
| （某些动物）冬眠，蛰伏( hibernate的第三人称单数 ) | |
参考例句： |
|
|
|
|
25
underlying
|
|
| adj.在下面的，含蓄的，潜在的 | |
参考例句： |
|
|
|
|
26
collaborator
|
|
| n.合作者，协作者 | |
参考例句： |
|
|
|
|
27
analyze
|
|
| vt.分析，解析 (=analyse) | |
参考例句： |
|
|
|
|
28
analyzing
|
|
| v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析 | |
参考例句： |
|
|
|
购买
在百度中搜索