The Bering Sea is the only body of water that links the Arctic and Pacific Oceans. Rich in marine life and home to one of the world's most productive fishing grounds, it hugs Alaska to the west and Russia to the east and separates two continents, North America and Asia. And while it's both home and highway for salmon, crabs, whales, walruses and birds, it is also an efficient ice-maker. As with its counterparts further north in the Arctic Circle, in the Bering Sea the dance between ocean and atmosphere effects the quality and quantity of ice, which in turn impacts all of the life forms that converge in its waters.

We recently had the opportunity to fly over the Bering Sea between Nome and the Russian border. The breathtakingly clear day -- March 17, 2010 -- made for spectacular flying and provided a crystal-clear view of the frozen sea surface below. It was a first-time experience, and we couldn't help but notice the intricate shapes, textures and colors floating on the water beneath us. With our curiosity piqued, we turned to the National Snow and Ice Data Center in Colorado to walk us through the science of sea ice.

From pancake ice (small ice that forms in thin, rounded "pancake shapes") to polynyas (open water near islands where ice is formed and blown away), there are a lot of intricacies to nature's method for manufacturing sea ice.

In some of our images you'll notice a thin, translucent film on the water. But what appears to be a dark liquid coating is actually the newest of new ice, aptly called "grease ice," because, thin and pliable, it takes on the appearance of an oil sheen.

As ice matures it becomes thicker, stronger and able to support greater weight on its surface. That's important for the arctic wildlife that uses the ice for travel, rest and gathering food, but the surface isn't always as solid as one might assume. For example, polar bears have learned to adjust their body movement to compensate for less-than-sturdy ice sheets by belly skating along its surface, as demonstrated in a short BBC video production.

In addition to smooth, flat ice, northern seas also produce floating chunks of blocky, jumbled ice, as well as ice sheets with raised, serpentine mounds called pressure ridges. The different shapes, sizes and other defining characteristics of the ice result from different weather patterns, which vary by day, week, month and year. Winds from the north tend to blow cool air, which help freeze surface water and extend the arctic ice edge to the south, while winds from the south tend to be warmer, which push the ice edge inward and contribute to melting.

This winter, the Bering Sea has had an unusually productive ice-making season, something likely due to more northern winds, according to the National Snow and Ice Data Center. But more ice on Alaska's western coast doesn't mean the polar ice cap is reversing its melting trend. While ice extent in the Bering Sea is above normal, ice production in arctic waters further to the north remains below normal.

Additional information on arctic sea ice can be found online at the National Oceanic and Atmospheric Administration.

Contact Jill Burke at jill(at)alaskadispatch.com. Contact Stephen Nowers at stephen(at)alaskadispatch.com.