VOA慢速英语--北方海豹种群在意想不到的地方繁殖

Northern Fur Seal Population Growing in Unlikely Place

For 30 years, Alaska’s northern fur seal population has not increased. But the ocean mammals are appearing in growing numbers in one unlikely place -- a small island that forms the tip of an active undersea volcano.

Bogoslof Island is distant and unpopulated. It sits in the eastern Bering Sea. Openings on the ground there release mud, steam and sulfurous gases. But northern fur seals find the island to be a good place for giving birth and raising their young.

Tom Gelatt leads a group at the United States’ National Oceanic and Atmospheric¹ Administration, or NOAA. His group studies northern fur seals. Gelatt calls the population growth on Bogoslof “extraordinary.”

Most of the world’s 1.1 million northern fur seals live in the eastern Bering Sea area. The animals live in the ocean from November to June and return to land in summer, when they breed and nurse pups.

But it is unclear to scientists why the seals have chosen to live on an active volcanic² island instead of other unpopulated islands in the area. “The surface is covered with these big...blocks, some as big as 10 meters in length, that were exploded out of the vent³,” said Chris Waythomas. He is a U.S. Geological Survey research scientist at the Alaska Volcano Observatory⁴.

About 635,000 northern fur seals live in the eastern Bering Sea area.They were first seen on Bogoslof in 1980. NOAA researchers have since carried out periodic studies of the population. In 2015, scientists estimated there were about 28,000 pups on the island.

On Bogoslof, the seals hang out on the island’s rocky beaches. But they are never far away from signs of volcanic activity. The center of the island supports a field of fumaroles -- openings through which hot gases come out. Some make extremely loud noises. Mud bursts out from them and shoots several meters into the air, Waythomas said.

Northern fur seals get their name from their extremely thick fur; they have about 60,000 hairs per square centimeter. When Russian Emperor Alexander II needed money and decided⁵ to sell Alaska to the United States in 1867, fur was one of the future state’s known valuables.

Between 1950 and 1988, the northern fur seal population dropped from 2.1 million to 1.1 million. Scientists do not know why they have not made a comeback.

“That’s the million-dollar question,” Gelatt said.

Volcanic activity on Bogoslof has remained mostly stable. But Gelatt’s crew chose not to camp there during their week-long visit in August. They feared an explosion could shoot up huge rocks. Instead, they made day trips from a secured boat.

The crew counted the number of seals and examined whether images taken from above by an unpiloted aircraft could be used in future counts.

Gelatt said, “Barring other future catastrophic eruptions…there is plenty of room for a lot more seals on Bogoslof.”

I’m Ashley Thompson.

Words in This Story

pup - n. one of the young of various animals other than dogs

vent - n. an opening through which air, steam, smoke, liquid, etc., can go into or out of a room, machine, or container

stable - adj. a good state or condition that is not easily changed or likely to change

beach - n. an area covered with sand or small rocks that is next to an ocean or lake

catastrophic - adj. involving or creating sudden damage or danger

eruption⁶ - n. a sudden explosion that sends out rocks, ash, lava⁷, etc...

1 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

2 volcanic   

adj.火山的；象火山的；由火山引起的

参考例句：

• There have been several volcanic eruptions this year.今年火山爆发了好几次。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

3 vent   

n.通风口，排放口；开衩；vt.表达，发泄

参考例句：

• He gave vent to his anger by swearing loudly.他高声咒骂以发泄他的愤怒。
• When the vent became plugged,the engine would stop.当通风口被堵塞时，发动机就会停转。

4 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

5 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

6 eruption   

n.火山爆发；（战争等）爆发；（疾病等）发作

参考例句：

• The temple was destroyed in the violent eruption of 1470 BC.庙宇在公元前1470年猛烈的火山爆发中摧毁了。
• The eruption of a volcano is spontaneous.火山的爆发是自发的。

7 lava   

n.熔岩，火山岩

参考例句：

• The lava flowed down the sides of the volcano.熔岩沿火山坡面涌流而下。
• His anger spilled out like lava.他的愤怒像火山爆发似的迸发出来。