Scientists Link Antarctic Ice Melt to Decline in Staple Food

 

By David McAlary

Ocean animals in parts of Antarctica are facing a food shortage. A new British study finds that a staple¹ of the marine² wildlife diet, tiny shrimp-like creatures called krill, has dramatically decreased in abundance since the 1970s.  The researchers link the decline to loss of winter sea ice and possibly global warming.
 
Krill are one of the most important animals in the Southern Ocean food chain. These tiny shellfish, up to six centimeters long, feed on microscopic³ sea plants called phytoplankton. In turn, they are consumed by a wide range of ocean animals, including fish, whales, seals, penguins⁵, and some birds. They are also a potentially valuable source of protein for humans.
 
But the British Antarctic Survey has found a dramatic drop in krill populations in the waters off the Antarctic Peninsula, a region with half of all the Southern Ocean's krill stocks. The agency compared krill records gathered by nine countries since 1926.
 
"We found in that sector⁶, there was a large scale decline. And it was about, very roughly, an 80 percent decrease in krill abundance in the last 30 years," That is British Antarctic Survey marine biologist Angus Atkinson, the leader of the krill study that appears in the journal Nature.
 
Along with decreasing krill stocks, his team found a matching decline in the amount of Antarctic Peninsula sea ice in the winter. They say the reason for this apparent link may be that krill larvae⁷ depend on the ice for food and shelter from predators⁸ in order to grow into adulthood⁹.
 
"The krill need to survive the winter period when there is very little food in the water column and at that time, the sea ice is a critical resource for the baby krill to survive the winter," he added.  "That is because there is a carpet of algae¹⁰ attached to the underside of the ice, which acts as a concentrated food. And the overall decline in winter sea ice seems the explanation."
 
The British Antarctic Survey notes that global warming appears to be the cause for the sea ice melt. Temperatures in the Antarctic Peninsula have risen by two-and-a-half degrees Celsius¹¹ in the last 50 years. This is about five times more than the average global temperature rise.
 
Mr. Atkinson says if krill stocks fall too low, there might be detrimental¹² effects on animals that feed on it.  This is especially true of whales, whose populations already are low because of commercial hunting, now banned by an international whaling moratorium¹³.
 
"After that rapid depletion¹⁴ of whale numbers, other krill predators such as fur seals increased quite dramatically in abundance," he noted¹⁵.  "So if whales are going to become reestablished in Antarctica, we imagine they would have to compete with all these other higher predators, and they will be faced with greater scarcity¹⁶ of krill."
 
Mr. Atkinson says two recent studies show that the krill decline is already having an impact on some Antarctic penguin⁴ species, adversely¹⁷ affecting their foraging¹⁸ patterns and breeding numbers.

David McAlary, VOA News, Washington.

注释：
Antarctica 南极洲
staple 主食
marine 海洋中的
shrimp 小虾
food chain 食物链
microscopic 极小的
phytoplankton 浮游植物
seal 海豹
penguin 企鹅
British Antarctic Survey 英国南极勘查组
Antarctic Peninsula 南极半岛
algae 海藻
concentrated 浓缩的
forage 觅食

1 staple   

n.主要产物，常用品，主要要素，原料，订书钉，钩环；adj.主要的，重要的；vt.分类

参考例句：

• Tea is the staple crop here.本地产品以茶叶为大宗。
• Potatoes are the staple of their diet.土豆是他们的主要食品。

2 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• 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。

3 microscopic   

adj.微小的，细微的，极小的，显微的

参考例句：

• It's impossible to read his microscopic handwriting.不可能看清他那极小的书写字迹。
• A plant's lungs are the microscopic pores in its leaves.植物的肺就是其叶片上微细的气孔。

4 penguin   

n.企鹅

参考例句：

• The penguin is a flightless bird.企鹅是一种不会飞的鸟。
• He walked with an awkward gait like a penguin.他走路的步子难看得就像企鹅。

5 penguins   

n.企鹅( penguin的名词复数 )

参考例句：

• Why can penguins live in cold environment? 为什么企鹅能生活在寒冷的环境中？ 来自《简明英汉词典》
• Whales, seals, penguins, and turtles have flippers. 鲸、海豹，企鹅和海龟均有鳍形肢。 来自《现代英汉综合大词典》

6 sector   

n.部门，部分；防御地段，防区；扇形

参考例句：

• The export sector will aid the economic recovery. 出口产业将促进经济复苏。
• The enemy have attacked the British sector.敌人已进攻英国防区。

7 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

8 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• 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》

9 adulthood   

n.成年，成人期

参考例句：

• Some infantile actions survive into adulthood.某些婴儿期的行为一直保持到成年期。
• Few people nowadays are able to maintain friendships into adulthood.如今很少有人能将友谊维持到成年。

10 algae   

n.水藻，海藻

参考例句：

• Most algae live in water.多数藻类生长在水中。
• Algae grow and spread quickly in the lake.湖中水藻滋蔓。

11 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。

12 detrimental   

adj.损害的，造成伤害的

参考例句：

• We know that heat treatment is detrimental to milk.我们知道加热对牛奶是不利的。
• He wouldn't accept that smoking was detrimental to health.他不相信吸烟有害健康。

13 moratorium   

n.(行动、活动的)暂停(期)，延期偿付

参考例句：

• The government has called for a moratorium on weapons testing.政府已要求暂停武器试验。
• We recommended a moratorium on two particular kinds of experiments.我们建议暂禁两种特殊的实验。

14 depletion   

n.耗尽，枯竭

参考例句：

• Increased consumption of water has led to rapid depletion of groundwater reserves.用水量的增加导致了地下水贮备迅速枯竭。
• Farmers should rotate crops every season to prevent depletion of the soil.农夫每季应该要轮耕，以免耗尽土壤。

15 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

16 scarcity   

n.缺乏，不足，萧条

参考例句：

• The scarcity of skilled workers is worrying the government.熟练工人的缺乏困扰着政府。
• The scarcity of fruit was caused by the drought.水果供不应求是由于干旱造成的。

17 adversely   

ad.有害地

参考例句：

• We commented adversely upon the imbecility of that message of telegraphic style. 我们对着这条电报式的愚蠢的留言发泄了一通不满。
• Widely fluctuating exchange rates may adversely affect international trade. 浮动幅度很大的汇率可能会对国际贸易产生有害的影响。

18 foraging   

v.搜寻（食物），尤指动物觅（食）( forage的现在分词 )；（尤指用手）搜寻（东西）

参考例句：

• They eke out a precarious existence foraging in rubbish dumps. 他们靠在垃圾场捡垃圾维持着朝不保夕的生活。 来自《简明英汉词典》
• The campers went foraging for wood to make a fire. 露营者去搜寻柴木点火。 来自辞典例句