Climate change could turn the Arctic Ocean into a high-speed ice superhighway. Large pieces of sea ice in the Arctic are becoming thinner as old ice melts. The new ice that’s replacing it travels farther and faster than the older ice had. As the younger ice travels, it carries dirt, organisms(微生物) and pollution along for the ride, new research shows.
Researchers have been tracking the movements of Arctic ice for several years. They noticed that the area covered by ice making the trip from one side of the ocean to the other has grown larger and larger. That movement means that far-away reaches of the Arctic are becoming more connected, notes Robert Newton, from Columbia University.
“The speedy ice is a problem,” he explains. “The ice in the Arctic is surprisingly polluted,” he said. “When the ice travels from one part of the Arctic to the other, it carries all that material with it.”
Winds sweep air pollution north from lower latitudes. Much of that pollution can settle into the ocean and onto sea ice. Industries along Arctic coastlines, such as gold mining and oil drilling, also can pollute the region’s waters. As new ice forms in fall and winter, that pollution gets trapped inside the ice. When that ice then melts in spring and summer, it’ll bring the pollution it carried back into the ocean.
In the study, the researchers put snapshots(快照) of the Arctic together. The pictures came from satellites far above the surface. They used computer software that can recognize the edges of sea ice. This allowed them to follow the movements of ice from forming to melting. To help them do that, they also included tracking buoys(浮标) on the ice that had been equipped with GPS devices.
They found about 60% of Arctic ice travels less than 100 kilometers from its birthplace. The rest covers an area equal to tens of thousands of square kilometers. It can travel hundreds or even thousands of kilometers. And that ice is moving faster as well.
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