SSS 2008-11-10

（单词翻译）

This is Scientific American's 60-Second Science. I'm Karen Hopkin. This will just take a minute.

Every year, scores of manatees¹ are killed by boats in Florida’s waters. Their plight² is an ecological³ concern. And everyone from marine⁴ biologists to Marge in an episode⁵ of the Simpsons has gotten on board to save the manatees. So far, the best idea they’ve come up with is posting speed limits for boaters that zip through Florida’s waterways. But local scientist Edmund Gerstein says that slowing boats down may do more harm than good.

According to Gerstein, manatees aren’t hit because they’re too slow to get out of the way. When they’re motivated, they can move about 21 feet in a second. Instead, he thinks that manatees can’t hear the boats coming. Gerstein’s found that manatees are deaf to the sort of low-frequency sounds produced by boat engines. Making boats move more slowly makes things worse, because the resulting sound is even harder for them to hear and the boats spend that much more time in the area. His results will be presented at the acoustical⁶ society meeting in Miami on November 13th.

Happily, Gerstein has designed an underwater alarm that, when attached to the front of a boat, tells manatees to move it. Which could lead Marge to say: [Marge Simpson voice] “I can believe how many manatees we saved today.”

Thanks for the minute for Scientific American's 60-Second Science. I'm Karen Hopkin.