The phytoplankton creating the turquoise bloom is coccolithophoe, a tiny marine plant that thrives in warm, nutrient-poor conditions, "so they are a harbinger of problems when they are in the Bering Sea," Duffy-Anderson said.

This is the second consecutive year the Bering Sea has been unusually warm -- and turquoise -- and scientists from NOAA, the University of Washington and the U.S. Fish and Wildlife Service are on a monthlong cruise aboard the research vessel Oscar Dyson to try to understand what is happening in these waters.