On the Canadian side of the Detroit River, a university student took an early morning walk. He saw a furry brown creature pop its head out from under the water. What's that? An otter for the first time in more than 100 years.
Hurray for a better ecosystem! Why? Until U.S. and Canadian laws made it illegal, factories dumped oil and petroleum in the river. Pollution made the water toxic and unlivable for the otters and the entire ecosystem. Scientist John Hartig says decades of cleanup have made a big difference. When the otters come back, he says, "good news for you and me. If the Detroit River is clean for river otters, it's cleaner for us as well."
故事发生在加拿大底特律河。不久前，当一名大学生在清晨的岸边散步时，他看到一个毛茸茸的棕色生物从水底冒出头来。是什么小动物呢？那是一只水獭！100年来第一次出现在这条河里。
故事到这里，大家应该给点喝彩声，为现在日益改善的生态系统欢呼! 100多年前，河岸边的工厂在底特律河里倾倒油料和石油，造成了环境污染。不仅使河水有毒，使得水獭无法生存，而且整个生态系统也迅速恶化。于是，美国和加拿大政府实行了相关禁止倾倒法律。几十年来，河流的清理工作已经产生了很大的变化。正如污染科学家约翰-哈蒂格（John Hartig）所说：“当水獭回来的时候，对你和我来说是个好消息。如果底特律河对河獭来说是干净的，那么它对我们来说也是干净的。"