2020托福听力练习：麦克风听海洋动物声音（下载）

　　"My colleagues and I always joke that one of the Jacques Cousteau movies starts out with something like the ocean is a silent place.

　　“And, you know, it's anything but silent.”

　　Kate Stafford is a biologist and oceanographer at the University of Washington.

　　And she and her colleagues have been cataloguing that soundscape of the deep—like these bowhead whales and bearded seals.

　　They're using an array of underwater microphones near the Bering Strait, a natural choke point for underwater traffic headed from the Pacific to the Arctic and back.

　　And in some ways, she says, listening is a better way to census the Arctic than seeing.

　　"You can record sounds underwater at night, when the region is ice coverd.

　　So we're able to eavesdrop all year round.

　　And you can hear animals much further underwater than you could, say, see them from the surface of the water."

　　But in the last five years of underwater recordings, Stafford says, no two years have been the same in terms of which species they hear, and when they hear them.

　　And as arctic ice retreats, species like humpbacks and killer whales are staying north longer—as late as early November—which she says would not have been possible just a few decades ago.

　　They even found humpbacks singing mating songs up in Arctic waters which they used to think happened only down in tropical breeding grounds.

　　The team presented these findings November 2 at a meeting of the Acoustical Society of America, in Jacksonville, Florida.

　　"If polar bears and walrus might be the ecological losers as it were in terms of sea ice loss, a lot of the larger whales seem to be taking advantage of this system.

　　It's a really good time to be a bowhead, as a colleague of mine says."

　　But uncertainty is the name of the game with Arctic change.

　　We'll see if it continues to be a good time to be a bowhead as more and more sub-Arctic whales move north to compete in Arctic waters.