Editor's Note: Woods Hole Oceanographic Institution oceanographer and photographer Chris Linder and science writer Helen Fields are taking part in a six-week cruise of the Bering Sea, a scientific expedition to study the effects of climate change on this polar ecosystem. This is the first blog post. To see all their posts, see "60 Seconds in the Bering Sea."

ON THE ICEBREAKER HEALY IN THE BERING SEA (at latitude 61.9978 N and longitude 173.2667 W), April 16, 2009--I stepped into the giant red exposure suit and slid my feet into the attached booties. I wormed my hands into the  skintight sleeves, and  squeezed my head through the neoprene  until it emerged. It's far from comfy, but will keep me dry if I happen to fall into 29-degree Fahrenheit (-1.7 Celsius) water–a real risk out here.

University of Alaska-Fairbanks graduate student Jessica Cross zips me into my suit.

Zipping into the MSD-900 suit gets me ready for one of the coolest things I get to do while I’m on Healy: walk on sea ice. The scientists on this research cruise are on a mission to learn  everything possible about the Bering Sea's ecosystem from the tiny organisms that live in its sea ice to the birds that fly overhead and the clams and worms in the mud on its floor. They collect a lot of samples from the ship, but also occasionally get off the ship to work on the ice itself.

Researchers exploring how water moves within the ice drill wells partway through the ice and return an hour or so later to study the brine (salty water that travels in channels through the ice) that collects in them. David Shull, a benthic ecologist from Western Washington University in Bellingham, Wash., moves a toaster-sized remotely operated vehicle, or ROV, under the ice; the device measures oxygen produced by algae. Pat Kelly, an oceanographer from the University of Rhode Island, attaches sediment traps to a rope and lowers them through the ice to hang in the water. Each trap is a water-filled tube that collects “marine snow” – mostly dead algae and zooplankton poop – as it falls toward the bottom.

This morning a stop at an ice station was on the agenda. Katrin Iken, a biologist from the University of Alaska – Fairbanks, has been on the ship’s bridge since 5:30 a.m., looking for a “nice, soccer field-size piece of ice,” at least 18 inches thick. It's about 9 a.m. when the Healy pulls up to a promising-looking ice floe.

Katrin Iken shows how thick she thinks the ice is.

The scientists  set to go out onto the ice gather in the helicopter hangar on board to hear about the plan for the ice from Commander Jeff Stewart, the ship’s operations officer.  It's a balmy 22 degrees Fahrenheit (-5.5 degrees C), practically a heat wave after two weeks of temperatures in the single digits and teens. “Protective equipment and practices are the same as before,” Stewart says. The only exception: the ship’s foghorn-like whistle has been turned off because the extreme cold was making it go off randomly. In case of an emergency such as a hungry polar bear, we’ll hear a hand-held air horn instead.

We were all ready to go when things took a turn for the worse. Just as three Coast Guard crew members were standing on the ice near the bottom of the ramp, checking it for safety, the ice broke. “It went from a little crack way over there to spilling water here in a minute and a half,” John Rose, the ship’s boatswain, told me. No one was hurt, but a crew member had to be sent down to crawl around gingerly, retrieving equipment and piling it on a sled.

Boatswain’s mate Evan Roy crawls across the ice to snag a piece of gear that fell off the ramp.

An hour later, the ship was lined up by a new patch of ice. I squeezed into that big red suit, University of Alaska-Fairbanks graduate student Jessica Cross zipped me up, and we all tramped down the ramp on to the ice.

University of Washington nutrient chemist Calvin Mordy works on the ice.

Images: Photos by Chris Linder, WHOI