Across the Arctic

Scientists and crew aboard the Swedish icebreaker Oden search for narrow cracks in the ice, called leads. Traveling through leads makes navigation easier. (Photo by Peter Winsor, WHOI)

The U.S. Coast Guard icebreaker Healy was photographed from the deck of the research vessel Oden. The vessels worked in tandem to break through Arctic ice. (Photo by Bob Newton, Lamont-Doherty Earth Observatory )

WHOI scientist Luc Rainville "supports" the bow of the icebreaker Oden during a half-day stop at the North Pole, midway through the expedition. Icebreakers often ride atop sea ice and come down on it to smash open passages. (Photo by Peter Winsor, WHOI)

Ship lights illuminate an iceberg near the fantail while the vessel was stopped for research. (Photo by Peter Winsor, WHOI)

Scientists and crew from the two icebreakers held meetings to coordinate operations. Here a crane transports scientists between icebreakers to hold a meeting. Most days, though, they shuttled by helicopter. (Photo by Peter Winsor, WHOI)

WHOI scientist Peter Winsor takes a break from a snowball fight during a stop to sample ice. "Below my feet were three meters of ice and 4,000 meters of sea water," he said. (Photo by Luc Rainville, WHOI)

WHOI scientist Peter Winsor peers into a hole cut into the ice to deploy an instrument into the ocean underneath. "It was nice hanging out there, on the ship's fantail, with ice stretched as far as I could see," he said. "I felt alone in the Arctic." (Photo by Peter Winsor, WHOI)

This soggy polar bear was one of 16 that scientists spotted in a single day. "He was running along the side of the ship, swimming between ice floes," he said. (Photo by Peter Winsor, WHOI)

These torpedo-shaped instruments, called polar profiling floats, drift nose-up at various depths through the Arctic Ocean while measuring water temperature and salinity. The floats are programmed to rise to the surface periodically and send data via satellite antenna to scientists on shore. (Photo by Peter Winsor, WHOI)

On the third or fourth day of the expedition, scientist Peter Winsor deployed the first of three polar profiling floats in a relatively ice-free area north of Alaska. (Photo by Peter Winsor, WHOI)

Researchers used Oden's helicopter to transport people between the two icebreakers, scout for leads in the ice, and look for open water needed to deploy some instruments. (Photo by Martin Jakobsson, Stockholm University)

U.S. Coast Guard icebreaker Healy was one of two vessels used during the Arctic cruise. (Photo by Martin Jakobsson, Stockholm University)