Deep sea special: The curious afterlife of whales

 作者:戴鬼     |      日期:2019-04-04 05:08:11
By Graham Lawton NEXT time a whale becomes stranded on a beach in New Zealand, Craig Smith will be secretly hoping that any rescue attempts fail, so that he can tow the dead whale out to sea, strap a couple of tonnes of scrap metal to it, and dispatch it to a watery grave. Smith, a marine biologist at the University of Hawaii at Manoa, has been sinking dead whales in this way since 1992. It’s smelly and expensive – each sinking costs about $8000 – which is why he’s only done it seven times. But with each whale sunk, Smith learns a little bit more about one of the oddest and most fascinating habitats on the ocean floor. “Whale falls” host bizarre communities of creatures that feed off the whale’s huge carcass. They can last for decades, perhaps as long as a century, and support a succession of weird and wonderful organisms, some of which only live on dead whales. In terms of species richness, researchers are coming to realise that whale falls are right up there with hydrothermal vents and cold seeps (see “Springtime in the abyss”). “They are the biodiversity hotspots of the deep ocean floor,” says Smith. Biologists had long wondered what happens to whales that die in the open sea. As long ago as 1934, the Danish zoologist August Krogh speculated that dead whales sink to the bottom and are eaten by whatever lives down there. But it was more than half a century before researchers saw what becomes of a dead whale. In 1987,