The cold, nutrient-rich waters of the Bering Sea support an incredibly productive ecosystem. Microscopic plants called algae bloom in the water and under the ice, feeding larger plankton. These organisms form the base of a food web that includes seals, walrus, whales, and humans. As temperatures rise, how will the reduction in ice extent affect this delicately balanced ecosystem? Scientists studied the tiny critters at the base of the food chain on this 40-day expedition.