Observed in the little-studied Amundsen Sea (see map), the brilliant blooms owe their colors to chlorophyll, a pigment in various types of phytoplankton, or tiny algae. Algae-eating zooplankton, small crustaceans called krill, and fish and shrimp larvae also thrive in the area.

A recent scientific expedition studied the blooms while plying the Amundsen Sea's polynya, a  region of seasonally open water surrounded by sea ice.

Often hundreds of miles wide, polynyas are nutrient-rich "oases" that offer refuges for animals big and small, according to Patricia Yager, chief scientist for the Amundsen Sea Polynya International Research Expedition (ASPIRE), which is funded by the