VOA科学技术2024--Sea Otters Help Save California’s Wetlands

Sea Otters² Help Save California’s Wetlands

　　At one point, it was nearly impossible to see sea otters along the west coast of the United States.

　　The animals were hunted nearly to extinction³ in the 1800s. People paid for their fur. At one point, only about 2,000 remained. Most lived in the waters off Alaska.

　　But by the 1980s, the animals started to recover. Three programs helped increase their population in northern California. First, hunters were banned from killing⁴ the otters. Next, an environmental program restored the wetlands where the otters once lived. And finally, California's Monterey Bay Aquarium⁵ began to raise otters and release them into the wild.

　　For about 40 years, the animals have been back in the seaside area called Elkhorn Slough⁷. It is between Monterey and San Francisco.

　　Brent Hughes is studying how the otters' return affected⁸ the environment. He is a marine⁹ ecologist at nearby Sonoma State University.

　　He recently published a report in the science journal Nature. Hughes and his team looked at a wetland area called a tidal estuary¹⁰. The researchers found that the otters perform a service that keeps the area from eroding¹¹ -- or wearing away.

　　Hughes said the otters feed on a destructive shellfish called the striped shore crab¹². The crabs¹³ dig into the mud and sand and bite the roots of a marsh¹⁴ grass known as pickleweed. Pickleweed holds the soil in place during coastal¹⁵ flooding.

　　The holes the crabs make cause the area to look like "Swiss cheese," Hughes said. Swiss cheese is a kind of cheese with many holes.

　　For the new study, researchers examined erosion rates dating back to the 1930s. The historical data help the researchers understand the effects of sea otters' return to the area.

　　The researchers also set up fences that prevented the otters from entering certain areas for three years. In the fenced-off section of the estuary, the scientists say the soil eroded¹⁷ much more quickly.

　　Hughes said the otters "don't completely reverse erosion but slow it down to natural levels."

　　The otter¹ study is one of several research projects that follow what happens to an area when a top predator¹⁸ returns after a long period of time.

　　A famous past study looked at the return of gray wolves to Yellowstone National Park. The wolves hunted elk⁶ and moose that ate small trees along riverbanks. With fewer elk and moose, the trees started growing again and the riverbanks did not erode¹⁶ as quickly.

　　Something similar happened when the otters returned.

　　Johan Eklof is a Swedish marine biologist from Stockholm University who reviewed the study. Other studies, he noted¹⁹, depended only on observation. But this new study leaves no doubt that the otters limit erosion.

　　Other studies show that otters can be helpful for plants. One study said the otters eat sea creatures called urchins²⁰ that feed on kelp. The return of the otters permitted the kelp to grow again.

　　Brian Silliman is a coastal ecologist from Duke University in North Carolina. He co-wrote the new study. He described the otters as "amazing finders and eaters."

　　Words in This Story

　　extinction –n. the state or situation that results when something (such as a plant or animal species) has died out completely

　　affect –v. to produce an effect on something

　　certain –n. a known place or area

　　predator –n. an animal that lives by killing and eating other animals

1 otter   

n.水獭

参考例句：

• The economists say the competition otter to the brink of extinction.经济学家们说，竞争把海獭推到了灭绝的边缘。
• She collared my black wool coat with otter pelts.她把我的黑呢上衣镶上了水獭领。

2 otters   

n.（水）獭( otter的名词复数 )；獭皮

参考例句：

• An attempt is being made to entice otters back to the river. 人们正试图把水獭引诱回河里去。 来自《简明英汉词典》
• Otters are believed to have been on Earth for 90 million years. 水獭被认为存活在地球上已经9千多万年。 来自互联网

3 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

4 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

5 aquarium   

n.水族馆，养鱼池，玻璃缸

参考例句：

• The first time I saw seals was in an aquarium.我第一次看见海豹是在水族馆里。
• I'm going to the aquarium with my parents this Sunday.这个星期天，我要和父母一起到水族馆去。

6 elk   

n.麋鹿

参考例句：

• I was close enough to the elk to hear its labored breathing.我离那头麋鹿非常近，能听见它吃力的呼吸声。
• The refuge contains the largest wintering population of elk in the world.这座庇护所有着世界上数量最大的冬季麋鹿群。

7 slough   

v.蜕皮，脱落，抛弃

参考例句：

• He was not able to slough off the memories of the past.他无法忘记过去。
• A cicada throws its slough.蝉是要蜕皮的。

8 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

9 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。

10 estuary   

n.河口，江口

参考例句：

• We live near the Thames estuary.我们的住处靠近泰晤士河入海口。
• The ship has touched bottom.The estuary must be shallower than we thought.船搁浅了。这河口的水比我们想像的要浅。

11 eroding   

侵蚀，腐蚀( erode的现在分词 )； 逐渐毁坏，削弱，损害

参考例句：

• The coast is slowly eroding. 海岸正慢慢地被侵蚀。
• Another new development is eroding the age-old stereotype of the male warrior. 另一个新现象是，久已形成的男人皆武士的形象正逐渐消失。

12 crab   

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。

13 crabs   

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》

14 marsh   

n.沼泽，湿地

参考例句：

• There are a lot of frogs in the marsh.沼泽里有许多青蛙。
• I made my way slowly out of the marsh.我缓慢地走出这片沼泽地。

15 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

16 erode   

v.侵蚀，腐蚀，使...减少、减弱或消失

参考例句：

• Once exposed,soil is quickly eroded by wind and rain.一旦暴露在外，土壤很快就会被风雨侵蚀。
• Competition in the financial marketplace has eroded profits.金融市场的竞争降低了利润。

17 eroded   

adj. 被侵蚀的，有蚀痕的 动词erode的过去式和过去分词形式

参考例句：

• The cliff face has been steadily eroded by the sea. 峭壁表面逐渐被海水侵蚀。
• The stream eroded a channel in the solid rock. 小溪在硬石中侵蚀成一条水道。

18 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

19 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。

20 urchins   

n.顽童( urchin的名词复数 )；淘气鬼；猬；海胆

参考例句：

• Some dozen barefooted urchins ganged in from the riverside. 几十个赤足的顽童从河边成群结队而来。 来自《简明英汉词典》
• People said that he had jaundice and urchins nicknamed him "Yellow Fellow." 别人说他是黄胆病，孩子们也就叫他“黄胖”了。 来自汉英文学 - 中国现代小说