VOA慢速英语--快速蔓延的海胆在加州和俄勒冈州破坏海洋生态

Scientists say fast-spreading sea urchins² have eaten away at huge underwater kelp forests in California and Oregon.

The invasion by tens of millions of the sea creatures is causing the destruction of important forms of sea life.

A recent count found 350 million purple sea urchins on one Oregon reef alone. That is more than a 10,000 percent increase since 2014. In Northern California, 90 percent of large kelp forests have been swallowed up by the urchins.

Scientists have reported finding so-called "urchin¹ barrens," or huge stretches of the seafloor that contain nothing but sea urchins. Such growth has spread from California to waters off the state of Oregon, where kelp forests were once so thick that boats had trouble passing through.

Scott Groth is a shellfish scientist with Oregon's Department of Fish and Wildlife. "We're in uncharted territory," he told The Associated Press. "You can't just go out and smash them. There's too many. I don't know what we can do."

The explosion of purple sea urchins is one of the many problems now facing the Pacific Northwest's ocean environment.

Kelp has already been struggling because of warmer-than-usual waters in the Pacific Ocean. In 2013, a mysterious disease began destroying tens of millions of starfish. One starfish species, called the sunflower sea star, is the only known creature that seeks to feed on the purple sea urchin.

Also around 2013, the purple urchins had two very good mating years. With no animals feeding on the urchins, their numbers continued to grow.

Steve Rumrill is a shellfish expert at Oregon's wildlife agency. He told the AP the huge growth is being driven by starvation. "You can imagine all of these small urchins growing up, each one of them looking for food, desperate for food," he said. Rumrill added that while he has seen major population changes in sea urchins before, nothing comes close to the latest explosion.

Scientists say they are not yet sure if climate change is to blame. But they suspect it did play a part in the events that helped the purple urchins spread so quickly and widely.

Norah Eddy³ is a director at the Nature Conservancy California's oceans program. She gave another reason for the explosion. She said the area's kelp, which has already been weakened by warming waters, is not able to regrow itself as well as in the past.

"We're going to see climate change as a big driver of changes in kelp forests as we move forward, and we are already seeing that," Eddy told the AP. She is leading an effort to use drones to map and observe Northern California's remaining kelp forests.

The destruction is also having economic effects. Until now, red abalone and red sea urchins, a larger and meatier species of urchin, supported strong fishing businesses in California and Oregon.

A study released this week by the University of California, Davis found that 96 percent of red abalone had disappeared from California's northern coast.

Last year, California closed its red abalone fishery, which had brought an estimated $44 million into the coastal⁴ economy every year. In Oregon, officials suspended permits for its 300 abalone divers⁵ for three years.

I'm Bryan Lynn.

The Associated Press reported on this story. Bryan Lynn adapted the report for VOA Learning English. Ashley Thompson was the editor.

Words in This Story

kelp – n. a large, brown plant that grows in the sea

reef – n. a line of rocks or sand at or near the surface of the sea

barren – adj. unable to produce plants

uncharted – adj. never before described

species – n. a group of plants or animals that share similar qualities

desperate – adj. needing or wanting something very much

drone – n. an unmanned aircraft guided by remote control

1 urchin   

n.顽童；海胆

参考例句：

• You should sheer off the urchin.你应该躲避这顽童。
• He is a most wicked urchin.他是个非常调皮的顽童。

2 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

3 eddy   

n.漩涡，涡流

参考例句：

• The motor car disappeared in eddy of dust.汽车在一片扬尘的涡流中不见了。
• In Taylor's picture,the eddy is the basic element of turbulence.在泰勒的描述里，旋涡是湍流的基本要素。

4 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。

5 divers   

adj.不同的；种种的

参考例句：

• He chose divers of them,who were asked to accompany him.他选择他们当中的几个人，要他们和他作伴。
• Two divers work together while a standby diver remains on the surface.两名潜水员协同工作，同时有一名候补潜水员留在水面上。