For Bob, the tide pool is a natural laboratory.
对鲍勃来说,潮池是一个天然的实验室。
There are hunters, and filter feeders, scavengers, and plants giving food and shelter.
里面有捕食者、滤食性生物、食腐动物以及提供食物和庇护的植物。
And among the mussels, and barnacles, anemones, and snails, a large predator lurks.
在贻贝、藤壶、海葵和蜗牛中间,潜伏着一种大型捕食者。
Despite appearances, starfish are skilled hunters.
外表看上去虽无害,但海星其实是颇具手段的猎手。
Each of their arms carry eye-like sensors.
它们的每只触手上都带有类似眼睛的传感器。
Starfish use their tubed feet to pursue prey.
海星会用它们的管足来追逐猎物。
They can pry open mussels, devouring them in their shells.

Here, Paine conducts one of the simplest experiments in the history of biology.
在这里,潘恩进行了生物学史上最简单的实验之一。
He removes starfish from one tide pool while leaving them in another.
他把海星从一个潮池里捞出来,然后放到另一个潮池里。
Months after months, Paine returns, clearing out starfish.
几个月之后,潘恩回来清理海星,
And he sees the tide pool changing.
结果他发现潮池在变化。
There are more mussels, but less of everything else.
贻贝的数量增加了,其他物种的数量却减少了。
Eight years later, the impact is dramatic.
八年之后,这种影响是巨大的,
The mussels are all that remain.
潮池里只剩下贻贝了。
That indicates that the starfish have been preventing the mussels from taking over.
这表明海星一直在阻止贻贝称霸。
The predator maintains the entire community from the top down.
捕食者从上到下维持着整个群落的运行。
Without them, it all falls apart.